Quarkus – Kubernetes extension (reinvestigated, part 7), Live Coding, via the “remote development mode”, of a Java application that is running in a container on a K3s Kubernetes cluster

In my previous article, I shared with you the steps I took, to remotely debug a Java application that is running in a container on a Kubernetes cluster in my already existing Linux demo environment.
_{[Quarkus – Kubernetes extension (reinvestigated, part 6), Remote debugging a Java application that is running in a container on a K3s Kubernetes cluster]}

Some years ago, I also wrote articles about the Quarkus Kubernetes Extension.

As a mentioned in my previous article, I wanted to have a look at some others aspects of the Quarkus Kubernetes Extension, that I came across.

Part of the “Developer Joy” is the so called “Remote Development”.
Run dev mode remotely with changes to local files immediately available in a containerize environment.
Read the Remote Development Mode guide
_{[https://quarkus.io/developer-joy/]}

Warning:
Do not use this in production. This should only be used in a development environment. You should not run production application in dev mode.
_{[https://quarkus.io/guides/maven-tooling#remote-development-mode]}

In my previous article the focus was on remote debugging.

In this article, you can read more about “Live Coding” and the remote development mode, so that changes made to the local files of a Java application that is running in a container on a Kubernetes cluster, become immediately visible.
_{[https://quarkus.io/guides/maven-tooling#remote-development-mode]}

The base for all of this was my already existing Linux demo environment, including Quarkus and K3s (a lightweight certified Kubernetes distribution) and setup via Vagrant, as described in a previous article.
_{[Quarkus – Kubernetes extension (reinvestigated, part 5), implementing a Service of service type LoadBalancer with K3s]}

I started with reading the “Remote Development Mode guide”.

Live Coding

Improve and expedite the inner loop development process with live coding where code changes are automatically reflected in your running application. code -> refresh browser -> repeat
Read the Dev Mode guide
_{[https://quarkus.io/developer-joy/]}

Development mode

Dev mode enables hot deployment with background compilation, which means that when you modify your Java files or your resource files and refresh your browser these changes will automatically take effect. This works too for resource files like the configuration property file. The act of refreshing the browser triggers a scan of the workspace, and if any changes are detected the Java files are compiled, and the application is redeployed, then your request is serviced by the redeployed application. If there are any issues with compilation or deployment an error page will let you know.
_{[https://quarkus.io/guides/maven-tooling#dev-mode]}

Remote development mode

It is possible to use development mode remotely, so that you can run Quarkus in a container environment (such as OpenShift) and have changes made to your local files become immediately visible.

This allows you to develop in the same environment you will actually run your app in, and with access to the same services.

Do not use this in production. This should only be used in a development environment. You should not run production application in dev mode.

To do this you must build a mutable application, using the mutable-jar format. Set the following properties in application.properties:

quarkus.package.jar.type=mutable-jar (1)
quarkus.live-reload.password=changeit (2)
quarkus.live-reload.url=http://my.cluster.host.com:8080 (3)

1. This tells Quarkus to use the mutable-jar format. Mutable applications also include the deployment time parts of Quarkus, so they take up a bit more disk space. If run normally they start just as fast and use the same memory as an immutable application, however they can also be started in dev mode.
2. The password that is used to secure communication between the remote side and the local side.
3. The URL that your app is going to be running in dev mode at. This is only needed on the local side, so you may want to leave it out of the properties file and specify it as a system property on the command line.

The mutable-jar is then built in the same way that a regular Quarkus jar is built, i.e. by issuing:

Before you start Quarkus on the remote host set the environment variable QUARKUS_LAUNCH_DEVMODE=true. If you are on bare metal you can set it via the export QUARKUS_LAUNCH_DEVMODE=true command and then run the application with the proper java -jar …​ command to run the application.

If you plan on running the application via Docker, then you’ll need to add -e QUARKUS_LAUNCH_DEVMODE=true to the docker run command. When the application starts you should now see the following line in the logs: Profile dev activated. Live Coding activated. You will also need to give the application the rights to update the deployment resources by adding RUN chmod o+rw -R /deployments after the COPY commands into your Dockerfile. For security reasons, this option should not be added to the production Dockerfile.

The remote side does not need to include Maven or any other development tools. The normal fast-jar Dockerfile that is generated with a new Quarkus application is all you need. If you are using bare metal launch the Quarkus runner jar, do not attempt to run normal dev mode.

_{[https://quarkus.io/guides/maven-tooling#remote-development-mode]}

So, in line with the “Remote Development Mode guide”, I proceeded with making some changes.

Setting up the application for using the remote development mode

Below, you can see an overview of my Linux demo environment, as described in my previous article:
_{[Quarkus – Kubernetes extension (reinvestigated, part 6), Remote debugging a Java application that is running in a container on a K3s Kubernetes cluster]}

So, next I wanted to try out the remote development mode, by running the “kubernetes-quickstart” application on my Linux demo environment and start making changes to my local files on my Windows laptop where I had the source code available in the IntelliJ IDEA.

For the Linux demo environment to start, from the Oracle VM VirtualBox Manager on my Windows laptop, I started the appliance (in “Headless Start” mode). 

Once the VM was running, for executing later manual steps, I used vagrant ssh to connect into the running VM.

Before I proceeded with the steps mentioned in the “Remote Development Mode guide”, I wanted to make some changes to the “kubernetes-quickstart” application, to simplify some things. I wanted to skip the remote debugging and only wanted 1 pod with 1 container with the running application.

Next, on my Windows laptop, in my shared folder, I navigated to kubernetes-quickstart\src\main\resources and changed the content of file application.properties to:
[in bold, I highlighted the changes]

quarkus.container-image.registry=localhost:8443
quarkus.container-image.username=mylocregusername
quarkus.container-image.password=mylocregpassword
quarkus.container-image.group=quarkus
quarkus.kubernetes.namespace=nl-amis-development
quarkus.kubernetes.ports."ports".container-port=8080
quarkus.kubernetes.ports."ports".host-port=8180
quarkus.kubernetes.ports."ports".node-port=30010
quarkus.kubernetes.replicas=1
quarkus.kubernetes.service-type=node-port
quarkus.kubernetes.remote-debug.enabled=true
quarkus.kubernetes.remote-debug.address-port=5005

Following the steps mentioned in the “Remote Development Mode guide”, next I changed the content of file application.properties to:
[in bold, I highlighted the changes]

quarkus.container-image.registry=localhost:8443
quarkus.container-image.username=mylocregusername
quarkus.container-image.password=mylocregpassword
quarkus.container-image.group=quarkus
quarkus.kubernetes.namespace=nl-amis-development
quarkus.kubernetes.ports."ports".container-port=8080
quarkus.kubernetes.ports."ports".host-port=8180
quarkus.kubernetes.ports."ports".node-port=30010
quarkus.kubernetes.replicas=1
quarkus.package.jar.type=mutable-jar (1)
quarkus.live-reload.password=mylivereloadpassword (2)

Step 1 tells Quarkus to use the mutable-jar format. Mutable applications also include the deployment time parts of Quarkus, so they take up a bit more disk space. If run normally they start just as fast and use the same memory as an immutable application, however they can also be started in dev mode.
_{[https://quarkus.io/guides/maven-tooling#remote-development-mode]}

Step 2 is the password that is used to secure communication between the remote side and the local side.
_{[https://quarkus.io/guides/maven-tooling#remote-development-mode]}

Remark about step 3:
As described in step 3, I opted to leave the URL out of the properties file, because it is only needed on the local side, and instead I will specify it as a system property on the command line.

Remark about quarkus.package.jar.type:

Packaging the application property	Type	Default
quarkus.package.jar.type The JAR output type to use. Environment variable: QUARKUS_PACKAGE_JAR_TYPE	fast-jar, uber-jar, mutable-jar, legacy-jar	fast-jar

_{[https://quarkus.io/guides/all-config]}

Remark about quarkus.live-reload.password:

Live reload property	Type	Default
quarkus.live-reload.password Password used to use to connect to the remote dev-mode application Environment variable: QUARKUS_LIVE_RELOAD_PASSWORD	string

_{[https://quarkus.io/guides/all-config]}

Setting the environment variable QUARKUS_LAUNCH_DEVMODE=true

As the “Remote Development Mode guide” mentioned, before you start Quarkus on the remote host set the environment variable QUARKUS_LAUNCH_DEVMODE=true. 
_{[https://quarkus.io/guides/maven-tooling#remote-development-mode]}

So, in order to add the environment variable, I changed the content of file application.properties to:
[in bold, I highlighted the changes]

quarkus.container-image.registry=localhost:8443
quarkus.container-image.username=mylocregusername
quarkus.container-image.password=mylocregpassword
quarkus.container-image.group=quarkus
quarkus.kubernetes.namespace=nl-amis-development
quarkus.kubernetes.ports."ports".container-port=8080
quarkus.kubernetes.ports."ports".host-port=8180
quarkus.kubernetes.ports."ports".node-port=30010
quarkus.kubernetes.replicas=1
quarkus.package.jar.type=mutable-jar
quarkus.live-reload.password=mylivereloadpassword
quarkus.kubernetes.env.vars.QUARKUS_LAUNCH_DEVMODE=true

Remark about adding a key/value pair as an environment variable:
To add a key/value pair as an environment variable in the generated resources:

quarkus.kubernetes.env.vars.my-env-var=foobar

The command above will add MY_ENV_VAR=foobar as an environment variable. Please note that the key my-env-var will be converted to uppercase and dashes will be replaced by underscores resulting in MY_ENV_VAR.
_{[https://quarkus.io/guides/deploying-to-kubernetes#environment-variables-from-keyvalue-pairs]}

Generation of Kubernetes manifests

In order to recreate the Kubernetes manifests, I used the following commands on the Linux Command Prompt:

cd /mnt/mysharedfolder/kubernetes-quickstart

mvn clean install -DskipTests

Remark about skipping tests:
To skip running the tests for a particular project, via the command line use -DskipTests.
_{[https://maven.apache.org/surefire/maven-surefire-plugin/examples/skipping-tests.html]}

With the following output:

WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::staticFieldBase has been called by com.google.inject.internal.aop.HiddenClassDefiner (file:/opt/apache-maven-3.9.11/lib/guice-5.1.0-classes.jar)
WARNING: Please consider reporting this to the maintainers of class com.google.inject.internal.aop.HiddenClassDefiner
WARNING: sun.misc.Unsafe::staticFieldBase will be removed in a future release
[INFO] Scanning for projects...
[INFO]
[INFO] -------------------< org.acme:kubernetes-quickstart >-------------------
[INFO] Building kubernetes-quickstart 1.0.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- clean:3.2.0:clean (default-clean) @ kubernetes-quickstart ---
[INFO] Deleting /mnt/mysharedfolder/kubernetes-quickstart/target
[INFO]
[INFO] --- resources:3.3.1:resources (default-resources) @ kubernetes-quickstart ---
[INFO] Copying 1 resource from src/main/resources to target/classes
[INFO]
[INFO] --- quarkus:3.25.2:generate-code (default) @ kubernetes-quickstart ---
[INFO]
[INFO] --- compiler:3.14.0:compile (default-compile) @ kubernetes-quickstart ---
[INFO] Recompiling the module because of changed source code.
[INFO] Compiling 1 source file with javac [debug parameters release 21] to target/classes
[INFO]
[INFO] --- quarkus:3.25.2:generate-code-tests (default) @ kubernetes-quickstart ---
[INFO]
[INFO] --- resources:3.3.1:testResources (default-testResources) @ kubernetes-quickstart ---
[INFO] skip non existing resourceDirectory /mnt/mysharedfolder/kubernetes-quickstart/src/test/resources
[INFO]
[INFO] --- compiler:3.14.0:testCompile (default-testCompile) @ kubernetes-quickstart ---
[INFO] Recompiling the module because of changed dependency.
[INFO] Compiling 2 source files with javac [debug parameters release 21] to target/test-classes
[INFO]
[INFO] --- surefire:3.5.3:test (default-test) @ kubernetes-quickstart ---
[INFO] Tests are skipped.
[INFO]
[INFO] --- jar:3.4.1:jar (default-jar) @ kubernetes-quickstart ---
[INFO] Building jar: /mnt/mysharedfolder/kubernetes-quickstart/target/kubernetes-quickstart-1.0.0-SNAPSHOT.jar
[INFO]
[INFO] --- quarkus:3.25.2:build (default) @ kubernetes-quickstart ---
[INFO] [io.quarkus.kubernetes.deployment.PropertyUtil] Kubernetes manifests are generated with 'The container port http' having default value '8080'. The app and manifests will get out of sync if the property 'quarkus.http.port' is changed at runtime.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  19.864 s
[INFO] Finished at: 2025-11-06T12:57:54Z
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal io.quarkus.platform:quarkus-maven-plugin:3.25.2:build (default) on project kubernetes-quickstart: Failed to build quarkus application: io.quarkus.builder.BuildException: Build failure: Build failed due to errors
[ERROR]         [error]: Build step io.quarkus.kubernetes.deployment.KubernetesProcessor#build threw an exception: java.lang.RuntimeException: Can't edit matching ports. No match found.
[ERROR]         at io.fabric8.kubernetes.api.model.ServiceSpecFluent.editMatchingPort(ServiceSpecFluent.java:731)
[ERROR]         at io.quarkus.kubernetes.deployment.AddNodePortDecorator.andThenVisit(AddNodePortDecorator.java:35)
[ERROR]         at io.quarkus.kubernetes.deployment.AddNodePortDecorator.andThenVisit(AddNodePortDecorator.java:15)
[ERROR]         at io.dekorate.kubernetes.decorator.NamedResourceDecorator.andThenVisit(NamedResourceDecorator.java:90)
[ERROR]         at io.dekorate.kubernetes.decorator.NamedResourceDecorator$ResourceVisitor.visit(NamedResourceDecorator.java:105)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitor.visit(Visitor.java:30)
[ERROR]         at io.fabric8.kubernetes.api.builder.VisitorWiretap.visit(VisitorWiretap.java:49)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitable.accept(Visitable.java:53)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitable.lambda$accept$1(Visitable.java:67)
[ERROR]         at java.base/java.util.Optional.ifPresent(Optional.java:178)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitable.accept(Visitable.java:59)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitable.accept(Visitable.java:39)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitable.accept(Visitable.java:35)
[ERROR]         at io.dekorate.kubernetes.decorator.NamedResourceDecorator.visit(NamedResourceDecorator.java:63)
[ERROR]         at io.dekorate.kubernetes.decorator.NamedResourceDecorator.visit(NamedResourceDecorator.java:29)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitor.visit(Visitor.java:30)
[ERROR]         at io.fabric8.kubernetes.api.builder.VisitorWiretap.visit(VisitorWiretap.java:49)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitable.accept(Visitable.java:53)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitable.lambda$accept$1(Visitable.java:67)
[ERROR]         at java.base/java.util.Optional.ifPresent(Optional.java:178)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitable.accept(Visitable.java:59)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitable.accept(Visitable.java:39)
[ERROR]         at io.fabric8.kubernetes.api.builder.Visitable.accept(Visitable.java:35)
[ERROR]         at io.dekorate.ResourceRegistry.lambda$generate$2(ResourceRegistry.java:181)
[ERROR]         at java.base/java.util.HashMap.forEach(HashMap.java:1430)
[ERROR]         at io.dekorate.ResourceRegistry.generate(ResourceRegistry.java:173)
[ERROR]         at io.dekorate.Session.generate(Session.java:293)
[ERROR]         at io.dekorate.Session.close(Session.java:256)
[ERROR]         at io.quarkus.kubernetes.deployment.KubernetesProcessor.lambda$build$5(KubernetesProcessor.java:198)
[ERROR]         at java.base/java.util.Optional.ifPresent(Optional.java:178)
[ERROR]         at io.quarkus.kubernetes.deployment.KubernetesProcessor.build(KubernetesProcessor.java:141)
[ERROR]         at java.base/java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:735)
[ERROR]         at io.quarkus.deployment.ExtensionLoader$3.execute(ExtensionLoader.java:889)
[ERROR]         at io.quarkus.builder.BuildContext.run(BuildContext.java:255)
[ERROR]         at org.jboss.threads.ContextHandler$1.runWith(ContextHandler.java:18)
[ERROR]         at org.jboss.threads.EnhancedQueueExecutor$Task.doRunWith(EnhancedQueueExecutor.java:2651)
[ERROR]         at org.jboss.threads.EnhancedQueueExecutor$Task.run(EnhancedQueueExecutor.java:2630)
[ERROR]         at org.jboss.threads.EnhancedQueueExecutor.runThreadBody(EnhancedQueueExecutor.java:1622)
[ERROR]         at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1589)
[ERROR]         at java.base/java.lang.Thread.run(Thread.java:1447)
[ERROR]         at org.jboss.threads.JBossThread.run(JBossThread.java:501)
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

So, I got an error:

Can't edit matching ports. No match found.

In this case there are no Kubernetes manifest files created in the target/kubernetes/ directory.

I stumbled across this error before, as I described in a previous article.
Again, the workaround for me, was to temporary change the port from 8080 to for example 8090 in the line quarkus.kubernetes.ports.”ports”.container-port=8080 in the file application.properties and then execute the mvn clean install command, followed by an undo of that port change and then execute the mvn clean install command again, until the build succeeded and the Kubernetes manifest files were created again.
_{[Quarkus – Kubernetes extension (reinvestigated, part 4), implementing a Service of service type NodePort]}

In order to recreate the Kubernetes manifests again, I used the following commands on the Linux Command Prompt:

cd /mnt/mysharedfolder/kubernetes-quickstart

mvn clean install -DskipTests

With the following output:

WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::staticFieldBase has been called by com.google.inject.internal.aop.HiddenClassDefiner (file:/opt/apache-maven-3.9.11/lib/guice-5.1.0-classes.jar)
WARNING: Please consider reporting this to the maintainers of class com.google.inject.internal.aop.HiddenClassDefiner
WARNING: sun.misc.Unsafe::staticFieldBase will be removed in a future release
[INFO] Scanning for projects...
[INFO]
[INFO] -------------------< org.acme:kubernetes-quickstart >-------------------
[INFO] Building kubernetes-quickstart 1.0.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- clean:3.2.0:clean (default-clean) @ kubernetes-quickstart ---
[INFO] Deleting /mnt/mysharedfolder/kubernetes-quickstart/target
[INFO]
[INFO] --- resources:3.3.1:resources (default-resources) @ kubernetes-quickstart ---
[INFO] Copying 1 resource from src/main/resources to target/classes
[INFO]
[INFO] --- quarkus:3.25.2:generate-code (default) @ kubernetes-quickstart ---
[INFO]
[INFO] --- compiler:3.14.0:compile (default-compile) @ kubernetes-quickstart ---
[INFO] Recompiling the module because of changed source code.
[INFO] Compiling 1 source file with javac [debug parameters release 21] to target/classes
[INFO]
[INFO] --- quarkus:3.25.2:generate-code-tests (default) @ kubernetes-quickstart ---
[INFO]
[INFO] --- resources:3.3.1:testResources (default-testResources) @ kubernetes-quickstart ---
[INFO] skip non existing resourceDirectory /mnt/mysharedfolder/kubernetes-quickstart/src/test/resources
[INFO]
[INFO] --- compiler:3.14.0:testCompile (default-testCompile) @ kubernetes-quickstart ---
[INFO] Recompiling the module because of changed dependency.
[INFO] Compiling 2 source files with javac [debug parameters release 21] to target/test-classes
[INFO]
[INFO] --- surefire:3.5.3:test (default-test) @ kubernetes-quickstart ---
[INFO] Tests are skipped.
[INFO]
[INFO] --- jar:3.4.1:jar (default-jar) @ kubernetes-quickstart ---
[INFO] Building jar: /mnt/mysharedfolder/kubernetes-quickstart/target/kubernetes-quickstart-1.0.0-SNAPSHOT.jar
[INFO]
[INFO] --- quarkus:3.25.2:build (default) @ kubernetes-quickstart ---
[INFO] [io.quarkus.kubernetes.deployment.PropertyUtil] Kubernetes manifests are generated with 'The container port http' having default value '8080'. The app and manifests will get out of sync if the property 'quarkus.http.port' is changed at runtime.
[INFO] [io.quarkus.deployment.QuarkusAugmentor] Quarkus augmentation completed in 19821ms
[INFO]
[INFO] --- failsafe:3.5.3:integration-test (default) @ kubernetes-quickstart ---
[INFO] Tests are skipped.
[INFO]
[INFO] --- quarkus:3.25.2:native-image-agent (default) @ kubernetes-quickstart ---
[INFO] Missing native-image-agent-base-config directory with native image agent configuration to transform
[INFO]
[INFO] --- failsafe:3.5.3:verify (default) @ kubernetes-quickstart ---
[INFO] Tests are skipped.
[INFO]
[INFO] --- install:3.1.2:install (default-install) @ kubernetes-quickstart ---
[INFO] Installing /mnt/mysharedfolder/kubernetes-quickstart/pom.xml to /home/vagrant/.m2/repository/org/acme/kubernetes-quickstart/1.0.0-SNAPSHOT/kubernetes-quickstart-1.0.0-SNAPSHOT.pom
[INFO] Installing /mnt/mysharedfolder/kubernetes-quickstart/target/kubernetes-quickstart-1.0.0-SNAPSHOT.jar to /home/vagrant/.m2/repository/org/acme/kubernetes-quickstart/1.0.0-SNAPSHOT/kubernetes-quickstart-1.0.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  34.655 s
[INFO] Finished at: 2025-11-06T14:28:16Z
[INFO] ------------------------------------------------------------------------

Below, you can see the content of the target/kubernetes/kubernetes.yml Kubernetes manifests, provided by the Quarkus project packaging:
[in bold, I highlighted the changes with regard to remote development mode]

---
apiVersion: v1
kind: Service
metadata:
  annotations:
    app.quarkus.io/quarkus-version: 3.25.2
    app.quarkus.io/build-timestamp: 2025-11-06 - 14:27:59 +0000
  labels:
    app.kubernetes.io/name: kubernetes-quickstart
    app.kubernetes.io/version: 1.0.0-SNAPSHOT
    app.kubernetes.io/managed-by: quarkus
  name: kubernetes-quickstart
  namespace: nl-amis-development
spec:
  ports:
    - name: ports
      nodePort: 30010
      port: 8180
      protocol: TCP
      targetPort: 8080
  selector:
    app.kubernetes.io/name: kubernetes-quickstart
    app.kubernetes.io/version: 1.0.0-SNAPSHOT
  type: NodePort
---
apiVersion: apps/v1
kind: Deployment
metadata:
  annotations:
    app.quarkus.io/quarkus-version: 3.25.2
    app.quarkus.io/build-timestamp: 2025-11-06 - 14:27:59 +0000
  labels:
    app.kubernetes.io/name: kubernetes-quickstart
    app.kubernetes.io/version: 1.0.0-SNAPSHOT
    app.kubernetes.io/managed-by: quarkus
  name: kubernetes-quickstart
  namespace: nl-amis-development
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: kubernetes-quickstart
      app.kubernetes.io/version: 1.0.0-SNAPSHOT
  template:
    metadata:
      annotations:
        app.quarkus.io/quarkus-version: 3.25.2
        app.quarkus.io/build-timestamp: 2025-11-06 - 14:27:59 +0000
      labels:
        app.kubernetes.io/managed-by: quarkus
        app.kubernetes.io/name: kubernetes-quickstart
        app.kubernetes.io/version: 1.0.0-SNAPSHOT
    spec:
      containers:
        - env:
            - name: KUBERNETES_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
            - name: QUARKUS_LAUNCH_DEVMODE
              value: "true"
          image: localhost:8443/quarkus/kubernetes-quickstart:1.0.0-SNAPSHOT
          imagePullPolicy: Always
          name: kubernetes-quickstart
          ports:
            - containerPort: 8080
              name: ports
              protocol: TCP

Build and push a container image for my project

Next, in order to build and push a container image for my project, I used the following commands on the Linux Command Prompt:

cd /mnt/mysharedfolder/kubernetes-quickstart

mvn clean install -DskipTests -Dquarkus.container-image.build=true -Dquarkus.container-image.push=true

With the following output:

WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::staticFieldBase has been called by com.google.inject.internal.aop.HiddenClassDefiner (file:/opt/apache-maven-3.9.11/lib/guice-5.1.0-classes.jar)
WARNING: Please consider reporting this to the maintainers of class com.google.inject.internal.aop.HiddenClassDefiner
WARNING: sun.misc.Unsafe::staticFieldBase will be removed in a future release
[INFO] Scanning for projects...
[INFO]
[INFO] -------------------< org.acme:kubernetes-quickstart >-------------------
[INFO] Building kubernetes-quickstart 1.0.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- clean:3.2.0:clean (default-clean) @ kubernetes-quickstart ---
[INFO] Deleting /mnt/mysharedfolder/kubernetes-quickstart/target
[INFO]
[INFO] --- resources:3.3.1:resources (default-resources) @ kubernetes-quickstart ---
[INFO] Copying 1 resource from src/main/resources to target/classes
[INFO]
[INFO] --- quarkus:3.25.2:generate-code (default) @ kubernetes-quickstart ---
[INFO]
[INFO] --- compiler:3.14.0:compile (default-compile) @ kubernetes-quickstart ---
[INFO] Recompiling the module because of changed source code.
[INFO] Compiling 1 source file with javac [debug parameters release 21] to target/classes
[INFO]
[INFO] --- quarkus:3.25.2:generate-code-tests (default) @ kubernetes-quickstart ---
[INFO]
[INFO] --- resources:3.3.1:testResources (default-testResources) @ kubernetes-quickstart ---
[INFO] skip non existing resourceDirectory /mnt/mysharedfolder/kubernetes-quickstart/src/test/resources
[INFO]
[INFO] --- compiler:3.14.0:testCompile (default-testCompile) @ kubernetes-quickstart ---
[INFO] Recompiling the module because of changed dependency.
[INFO] Compiling 2 source files with javac [debug parameters release 21] to target/test-classes
[INFO]
[INFO] --- surefire:3.5.3:test (default-test) @ kubernetes-quickstart ---
[INFO] Tests are skipped.
[INFO]
[INFO] --- jar:3.4.1:jar (default-jar) @ kubernetes-quickstart ---
[INFO] Building jar: /mnt/mysharedfolder/kubernetes-quickstart/target/kubernetes-quickstart-1.0.0-SNAPSHOT.jar
[INFO]
[INFO] --- quarkus:3.25.2:build (default) @ kubernetes-quickstart ---
[INFO] [io.quarkus.kubernetes.deployment.PropertyUtil] Kubernetes manifests are generated with 'The container port http' having default value '8080'. The app and manifests will get out of sync if the property 'quarkus.http.port' is changed at runtime.
[INFO] [io.quarkus.container.image.jib.deployment.JibProcessor] Starting (local) container image build for jar using jib.
[WARNING] [io.quarkus.container.image.jib.deployment.JibProcessor] Base image 'registry.access.redhat.com/ubi9/openjdk-21-runtime:1.21' does not use a specific image digest - build may not be reproducible
[INFO] [io.quarkus.container.image.jib.deployment.JibProcessor] Using base image with digest: sha256:360822c35c5741f542ab78fe123e6c4d9b68e0113a88d6e0250bb1f377b17f29
[INFO] [io.quarkus.container.image.jib.deployment.JibProcessor] Container entrypoint set to [/opt/jboss/container/java/run/run-java.sh]
[INFO] [io.quarkus.container.image.jib.deployment.JibProcessor] Pushed container image localhost:8443/quarkus/kubernetes-quickstart:1.0.0-SNAPSHOT (sha256:40007537d5ad6078cedf8cf925d8544329d79ecfab2945245cb3a68f24eeaf8d)

[INFO] [io.quarkus.deployment.QuarkusAugmentor] Quarkus augmentation completed in 46173ms
[INFO]
[INFO] --- failsafe:3.5.3:integration-test (default) @ kubernetes-quickstart ---
[INFO] Tests are skipped.
[INFO]
[INFO] --- quarkus:3.25.2:native-image-agent (default) @ kubernetes-quickstart ---
[INFO] Missing native-image-agent-base-config directory with native image agent configuration to transform
[INFO]
[INFO] --- failsafe:3.5.3:verify (default) @ kubernetes-quickstart ---
[INFO] Tests are skipped.
[INFO]
[INFO] --- install:3.1.2:install (default-install) @ kubernetes-quickstart ---
[INFO] Installing /mnt/mysharedfolder/kubernetes-quickstart/pom.xml to /home/vagrant/.m2/repository/org/acme/kubernetes-quickstart/1.0.0-SNAPSHOT/kubernetes-quickstart-1.0.0-SNAPSHOT.pom
[INFO] Installing /mnt/mysharedfolder/kubernetes-quickstart/target/kubernetes-quickstart-1.0.0-SNAPSHOT.jar to /home/vagrant/.m2/repository/org/acme/kubernetes-quickstart/1.0.0-SNAPSHOT/kubernetes-quickstart-1.0.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  57.813 s
[INFO] Finished at: 2025-11-06T14:31:15Z
[INFO] ------------------------------------------------------------------------

Removing the created Kubernetes objects

So, as I mentioned in my previous article, the Quarkus generated manifest kubernetes.yml, was already applied before to the Kubernetes cluster and created the following Kubernetes objects (in my custom nl-amis-development namespace):

• Service
• Deployment
• Replica Set
• Pod

Because I wanted to create the Kubernetes objects again, first I had to delete the existing ones. I repeated some of the steps I already described in a previous article.
_{[Quarkus – Kubernetes extension (reinvestigated, part 4), implementing a Service of service type NodePort]}

In order to delete the Replica Set and all of the dependent Pods (in the nl-amis-development namespace), I used the following command on the Linux Command Prompt:

kubectl delete -n nl-amis-development replicaset $(kubectl get replicasets -n nl-amis-development -o=jsonpath='{range .items..metadata}{.name}{"\n"}{end}' | grep kubernetes-quickstart- | awk '{print $1}')

With the following output:

replicaset.apps "kubernetes-quickstart-dcd557cfd" deleted

To delete a ReplicaSet and all of its Pods, use kubectl delete. The Garbage collector automatically deletes all of the dependent Pods by default.
_{[https://kubernetes.io/docs/concepts/workloads/controllers/replicaset/#deleting-a-replicaset-and-its-pods]}

In order to delete the Deployment, I used the following command on the Linux Command Prompt:

kubectl delete -n nl-amis-development deployment kubernetes-quickstart

With the following output:

deployment.apps "kubernetes-quickstart" deleted

In order to delete the Service, I used the following command on the Linux Command Prompt:

kubectl delete -n nl-amis-development service kubernetes-quickstart

With the following output:

service "kubernetes-quickstart" deleted

Recreating the Kubernetes objects in the nl-amis-development namespace, including a service with service type NodePort

Next, in order to recreate the Kubernetes manifests (in the nl-amis-development namespace), I used the following commands on the Linux Command Prompt:

cd /mnt/mysharedfolder/kubernetes-quickstart

kubectl apply -f target/kubernetes/kubernetes.yml

With the following output:

service/kubernetes-quickstart created
deployment.apps/kubernetes-quickstart created

Remark:
Be aware that I already created the nl-amis-development namespace object.

Then, I quickly checked whether the Pods were running successfully, via a series of command on the Linux Command Prompt.

kubectl get services --all-namespaces

With the following output:

NAMESPACE              NAME                        TYPE           CLUSTER-IP     EXTERNAL-IP   PORT(S)                      AGE
default                kubernetes                  ClusterIP      10.43.0.1      <none>        443/TCP                      85d
kube-system            kube-dns                    ClusterIP      10.43.0.10     <none>        53/UDP,53/TCP,9153/TCP       85d
kube-system            metrics-server              ClusterIP      10.43.45.122   <none>        443/TCP                      85d
kube-system            traefik                     LoadBalancer   10.43.141.14   10.0.2.15     80:30268/TCP,443:32611/TCP   85d
kubernetes-dashboard   dashboard-metrics-scraper   ClusterIP      10.43.18.175   <none>        8000/TCP                     85d
kubernetes-dashboard   kubernetes-dashboard        ClusterIP      10.43.77.188   <none>        443/TCP                      85d
nl-amis-development    kubernetes-quickstart       NodePort       10.43.109.8    <none>        8180:30010/TCP               10s

kubectl get replicasets --all-namespaces

With the following output:

NAMESPACE              NAME                                   DESIRED   CURRENT   READY   AGE
kube-system            coredns-5688667fd4                     1         1         1       85d
kube-system            local-path-provisioner-774c6665dc      1         1         1       85d
kube-system            metrics-server-6f4c6675d5              1         1         1       85d
kube-system            traefik-c98fdf6fb                      1         1         1       85d
kubernetes-dashboard   dashboard-metrics-scraper-749c668b7f   1         1         1       85d
kubernetes-dashboard   kubernetes-dashboard-76b75d676c        1         1         1       85d
nl-amis-development    kubernetes-quickstart-8579c4797d       1         1         1       42s

kubectl get daemonset --all-namespaces

With the following output:

NAMESPACE     NAME                     DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR   AGE
kube-system   svclb-traefik-dee09411   1         1         1       1            1           <none>          85d

kubectl get pods --all-namespaces

With the following output:

NAMESPACE              NAME                                         READY   STATUS      RESTARTS         AGE
kube-system            coredns-5688667fd4-2hqfj                     1/1     Running     31 (3h25m ago)   85d
kube-system            helm-install-traefik-crd-kp2hl               0/1     Completed   0                85d
kube-system            helm-install-traefik-vl7x8                   0/1     Completed   2                85d
kube-system            local-path-provisioner-774c6665dc-2b9pq      1/1     Running     19 (3h25m ago)   85d
kube-system            metrics-server-6f4c6675d5-lljlv              1/1     Running     29 (3h25m ago)   85d
kube-system            svclb-traefik-dee09411-c7lzh                 2/2     Running     38 (3h25m ago)   85d
kube-system            traefik-c98fdf6fb-stkt7                      1/1     Running     28 (3h25m ago)   85d
kubernetes-dashboard   dashboard-metrics-scraper-749c668b7f-s7rjt   1/1     Running     19 (3h25m ago)   85d
kubernetes-dashboard   kubernetes-dashboard-76b75d676c-tq8fk        1/1     Running     24 (3h25m ago)   85d
nl-amis-development    kubernetes-quickstart-8579c4797d-5bc2b       1/1     Running     0                81s

kubectl get endpoints --all-namespaces

With the following output:

Warning: v1 Endpoints is deprecated in v1.33+; use discovery.k8s.io/v1 EndpointSlice
NAMESPACE              NAME                        ENDPOINTS                                        AGE
default                kubernetes                  10.0.2.15:6443                                   85d
kube-system            kube-dns                    10.42.0.237:53,10.42.0.237:53,10.42.0.237:9153   85d
kube-system            metrics-server              10.42.0.234:10250                                85d
kube-system            traefik                     10.42.0.233:8000,10.42.0.233:8443                85d
kubernetes-dashboard   dashboard-metrics-scraper   10.42.0.232:8000                                 85d
kubernetes-dashboard   kubernetes-dashboard        10.42.0.236:8443                                 85d
nl-amis-development    kubernetes-quickstart       10.42.0.240:8080                                 104s

kubectl get endpoints -n nl-amis-development --output json

With the following output:

Warning: v1 Endpoints is deprecated in v1.33+; use discovery.k8s.io/v1 EndpointSlice
{
    "apiVersion": "v1",
    "items": [
        {
            "apiVersion": "v1",
            "kind": "Endpoints",
            "metadata": {
                "annotations": {
                    "endpoints.kubernetes.io/last-change-trigger-time": "2025-11-06T14:33:26Z"
                },
                "creationTimestamp": "2025-11-06T14:33:25Z",
                "labels": {
                    "app.kubernetes.io/managed-by": "quarkus",
                    "app.kubernetes.io/name": "kubernetes-quickstart",
                    "app.kubernetes.io/version": "1.0.0-SNAPSHOT",
                    "endpoints.kubernetes.io/managed-by": "endpoint-controller"
                },
                "name": "kubernetes-quickstart",
                "namespace": "nl-amis-development",
                "resourceVersion": "38865",
                "uid": "ecc05226-ce77-4c32-be16-e0f152d3084a"
            },
            "subsets": [
                {
                    "addresses": [
                        {
                            "ip": "10.42.0.240",
                            "nodeName": "ubuntu2204.localdomain",
                            "targetRef": {
                                "kind": "Pod",
                                "name": "kubernetes-quickstart-8579c4797d-5bc2b",
                                "namespace": "nl-amis-development",
                                "uid": "fcb6b17c-0abc-446d-8292-53728092f0e4"
                            }
                        }
                    ],
                    "ports": [
                        {
                            "name": "ports",
                            "port": 8080,
                            "protocol": "TCP"
                        }
                    ]
                }
            ]
        }
    ],
    "kind": "List",
    "metadata": {
        "resourceVersion": ""
    }
}

kubectl get nodes

With the following output:

NAME                     STATUS   ROLES                  AGE   VERSION
ubuntu2204.localdomain   Ready    control-plane,master   85d   v1.33.3+k3s1

In order to determine the IP of the K3s node, I used the following commands on the Linux Command Prompt, as I described in a previous article:
_{[Creating a re-usable Vagrant Box from an existing VM with Ubuntu and k3s (with the Kubernetes Dashboard) and adding mysql, using Vagrant and Oracle VirtualBox]}

nodeIP=$(kubectl get node ubuntu2204.localdomain -o yaml | grep address: | grep -E -o "([0-9]{1,3}[\.]){3}[0-9]{1,3}")
echo "---$nodeIP---"

With the following output:

---10.0.2.15---

In order to determine the nodePort of the K3s node, I used the following commands on the Linux Command Prompt, as I described in a previous article:
_{[Quarkus – Kubernetes extension (reinvestigated, part 5), implementing a Service of service type LoadBalancer with K3s]}

nodePort=$(kubectl get service kubernetes-quickstart -n nl-amis-development -o yaml | grep nodePort: | grep -E -o "[0-9]{5}")
echo "---$nodePort---"

With the following output:

---30010---

Below, you see an overview of my Kubernetes cluster at this moment:

Printing the logs for my container

As the “Remote Development Mode guide” mentioned, when the application starts you should see the following line in the logs: Profile dev activated. Live Coding activated.
_{[https://quarkus.io/guides/maven-tooling#remote-development-mode]}

In order to print the logs for a container in a pod, I used the following command on the Linux Command Prompt:
_{[https://kubernetes.io/docs/reference/kubectl/generated/kubectl_logs/]}

kubectl logs -n nl-amis-development kubernetes-quickstart-8579c4797d-5bc2b

With the following output:

INFO exec -a "java" java -XX:MaxRAMPercentage=80.0 -XX:+UseParallelGC -XX:MinHeapFreeRatio=10 -XX:MaxHeapFreeRatio=20 -XX:GCTimeRatio=4 -XX:AdaptiveSizePolicyWeight=90 -XX:+ExitOnOutOfMemoryError -Djava.util.logging.manager=org.jboss.logmanager.LogManager -Dquarkus.package.output-directory=${PWD} -cp "." -jar /home/jboss/quarkus-run.jar
INFO running in /home/jboss
Press [e] to edit command line args (currently ''), [h] for more options>
2025-11-06 14:33:30,786 INFO  [io.qua.kub.dep.PropertyUtil] (build-14) Kubernetes manifests are generated with 'The container port http' having default value '8080'. The app and manifests will get out of sync if the property 'quarkus.http.port' is changed at runtime.
2025-11-06 14:33:30,823 WARN  [io.qua.kub.dep.KubernetesProcessor] (build-6) No project was detected, skipping generation of kubernetes manifests!
2025-11-06 14:33:31,098 INFO  [org.tes.DockerClientFactory] (build-15) Testcontainers version: 1.21.3
2025-11-06 14:33:31,376 INFO  [org.tes.doc.DockerMachineClientProviderStrategy] (build-15) docker-machine executable was not found on PATH ([/usr/local/sbin, /usr/local/bin, /usr/sbin, /usr/bin, /sbin, /bin])
2025-11-06 14:33:31,378 ERROR [org.tes.doc.DockerClientProviderStrategy] (build-15) Could not find a valid Docker environment. Please check configuration. Attempted configurations were:
        UnixSocketClientProviderStrategy: failed with exception InvalidConfigurationException (Could not find unix domain socket). Root cause NoSuchFileException (/var/run/docker.sock)
        DockerDesktopClientProviderStrategy: failed with exception NullPointerException (Cannot invoke "java.nio.file.Path.toString()" because the return value of "org.testcontainers.dockerclient.DockerDesktopClientProviderStrategy.getSocketPath()" is null)As no valid configuration was found, execution cannot continue.
See https://java.testcontainers.org/on_failure.html for more details.
__  ____  __  _____   ___  __ ____  ______
 --/ __ \/ / / / _ | / _ \/ //_/ / / / __/
 -/ /_/ / /_/ / __ |/ , _/ ,< / /_/ /\ \
--\___\_\____/_/ |_/_/|_/_/|_|\____/___/
2025-11-06 14:33:33,171 INFO  [io.quarkus] (Quarkus Main Thread) kubernetes-quickstart 1.0.0-SNAPSHOT on JVM (powered by Quarkus 3.25.2) started in 6.580s. Listening on: http://0.0.0.0:8080
2025-11-06 14:33:33,172 INFO  [io.quarkus] (Quarkus Main Thread) Profile dev activated. Live Coding activated.
2025-11-06 14:33:33,173 INFO  [io.quarkus] (Quarkus Main Thread) Installed features: [cdi, compose, kubernetes, rest, smallrye-context-propagation, vertx]

So, indeed the profile dev was activated and also “Live Coding” was activated.

By the way, I opted to ignore the error about finding a valid Docker environment:

2025-11-06 14:33:31,378 ERROR [org.tes.doc.DockerClientProviderStrategy] (build-15) Could not find a valid Docker environment. Please check configuration. Attempted configurations were:
        UnixSocketClientProviderStrategy: failed with exception InvalidConfigurationException (Could not find unix domain socket). Root cause NoSuchFileException (/var/run/docker.sock)
        DockerDesktopClientProviderStrategy: failed with exception NullPointerException (Cannot invoke "java.nio.file.Path.toString()" because the return value of "org.testcontainers.dockerclient.DockerDesktopClientProviderStrategy.getSocketPath()" is null)As no valid configuration was found, execution cannot continue.
See https://java.testcontainers.org/on_failure.html for more details.

Calling the application

In order to forward local port 8090 to port 30100 on the K3s node ($nodeIP), I used the following command on the Linux Command Prompt, as I described in a previous article:
_{[https://technology.amis.nl/2020/04/30/creating-a-re-usable-vagrant-box-from-an-existing-vm-with-ubuntu-and-k3s-with-the-kubernetes-dashboard-and-adding-mysql-using-vagrant-and-oracle-virtualbox/]}

socat tcp-listen:8090,fork tcp:10.0.2.15:30010 &

With the following output:

[1] 39939

Then, in the Web Browser on my Windows laptop, I entered the URL:

http://localhost:8090/hello

Next, I continued reading the “Remote Development Mode guide”.

Connecting the local agent to the remote host

Now you need to connect your local agent to the remote host, using the remote-dev command:

./mvnw quarkus:remote-dev -Dquarkus.live-reload.url=http://my-remote-host:8080

Now every time you refresh the browser you should see any changes you have made locally immediately visible in the remote app. This is done via an HTTP based long polling transport, that will synchronize your local workspace and the remote application via HTTP calls.

If you do not want to use the HTTP feature then you can simply run the remote-dev command without specifying the URL. In this mode the command will continuously rebuild the local application, so you can use an external tool such as odo or rsync to sync to the remote application.
_{[https://quarkus.io/guides/maven-tooling#remote-development-mode]}

So, with remote development mode enabled, I used vagrant ssh to connect into the running VM from a second session.

In order to connect the local agent to the remote host, I used the following commands on the Linux Command Prompt:

cd /mnt/mysharedfolder/kubernetes-quickstart

mvn quarkus:remote-dev -Dquarkus.live-reload.url=http://localhost:8090

Remark about quarkus.live-reload.url:

Live reload property	Type	Default
quarkus.live-reload.url URL used to use to connect to the remote dev-mode application Environment variable: QUARKUS_LIVE_RELOAD_URL	string

_{[https://quarkus.io/guides/all-config]}

By the way, I could have used the following command on the Linux Command Prompt, which also works:

mvn quarkus:remote-dev -Dquarkus.live-reload.url=http://10.0.2.15:30010

With the following output:

WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::staticFieldBase has been called by com.google.inject.internal.aop.HiddenClassDefiner (file:/opt/apache-maven-3.9.11/lib/guice-5.1.0-classes.jar)
WARNING: Please consider reporting this to the maintainers of class com.google.inject.internal.aop.HiddenClassDefiner
WARNING: sun.misc.Unsafe::staticFieldBase will be removed in a future release
[INFO] Scanning for projects...
[INFO]
[INFO] -------------------< org.acme:kubernetes-quickstart >-------------------
[INFO] Building kubernetes-quickstart 1.0.0-SNAPSHOT
[INFO]   from pom.xml
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- quarkus:3.25.2:remote-dev (default-cli) @ kubernetes-quickstart ---
[INFO] Invoking resources:3.3.1:resources (default-resources) @ kubernetes-quickstart
[INFO] Copying 1 resource from src/main/resources to target/classes
[INFO] Invoking quarkus:3.25.2:generate-code (default) @ kubernetes-quickstart
[INFO] Invoking compiler:3.14.0:compile (default-compile) @ kubernetes-quickstart
[INFO] Nothing to compile - all classes are up to date.
[INFO] Invoking resources:3.3.1:testResources (default-testResources) @ kubernetes-quickstart
[INFO] skip non existing resourceDirectory /mnt/mysharedfolder/kubernetes-quickstart/src/test/resources
[INFO] Invoking quarkus:3.25.2:generate-code-tests (default) @ kubernetes-quickstart
[INFO] Invoking compiler:3.14.0:testCompile (default-testCompile) @ kubernetes-quickstart
[INFO] Nothing to compile - all classes are up to date.
Listening for transport dt_socket at address: 5005
2025-11-06 14:55:25,228 INFO  [io.qua.kub.dep.PropertyUtil] (build-26) Kubernetes manifests are generated with 'The container port http' having default value '8080'. The app and manifests will get out of sync if the property 'quarkus.http.port' is changed at runtime.
2025-11-06 14:55:39,655 INFO  [io.qua.dep.QuarkusAugmentor] (main) Quarkus augmentation completed in 16913ms
2025-11-06 14:55:49,253 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending app/kubernetes-quickstart-1.0.0-SNAPSHOT.jar
2025-11-06 14:55:49,263 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending quarkus-run.jar
2025-11-06 14:55:49,305 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending lib/deployment/appmodel.dat
2025-11-06 14:55:59,643 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Connected to remote server

Making a first change to the application code

On my Windows laptop in the IntelliJ IDEA I opened the source code of the GreetingResource class. As you may remember from a previous article, I had a shared folder available.
[Quarkus – Supersonic Subatomic Java – Get Started (reinvestigated)]

Below you can see the source code of the GreetingResource class:

package org.acme;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

@Path("/hello")
public class GreetingResource {

    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String hello() {
        return "Hello from Quarkus REST";
    }
}

So, then I changed the return value to:
[in bold, I highlighted the changes]

return "Hello from Quarkus REST. Live Coding demo, change A.";

Next, I refreshed the Web Browser on my Windows laptop.

From the second SSH session, I looked at the output on the Linux Command Prompt:

2025-11-06 15:16:26,425 INFO  [io.qua.dep.dev.RuntimeUpdatesProcessor] (Remote dev client thread) Restarting quarkus due to changes in GreetingResource.class.
2025-11-06 15:16:42,387 INFO  [io.qua.dep.QuarkusAugmentor] (Remote dev client thread) Quarkus augmentation completed in 15958ms
2025-11-06 15:16:42,471 INFO  [io.qua.dep.dev.RuntimeUpdatesProcessor] (Remote dev client thread) Live reload total time: 16.300s
2025-11-06 15:16:50,030 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending app/kubernetes-quickstart-1.0.0-SNAPSHOT.jar
2025-11-06 15:16:50,051 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending dev/app/org/acme/GreetingResource.class
2025-11-06 15:16:50,097 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending quarkus-run.jar
2025-11-06 15:16:50,784 ERROR [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Remote dev request failed: java.io.IOException: Server returned HTTP response code: 500 for URL: http://localhost:8090/dev
        at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1699)
        at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1301)
        at io.quarkus.vertx.http.deployment.devmode.HttpRemoteDevClient$Session.run(HttpRemoteDevClient.java:222)
        at java.base/java.lang.Thread.run(Thread.java:1447)

With the following output (after some time):

So the “Live Coding” was working. Changes to my local file were immediately available in my containerized environment 😊.

By the way, I opted to ignore the error about the remote dev request that failed, because despite this error the “Live Coding” was working:

2025-11-06 15:16:50,784 ERROR [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Remote dev request failed: java.io.IOException: Server returned HTTP response code: 500 for URL: http://localhost:8090/dev
        at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1699)
        at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1301)
        at io.quarkus.vertx.http.deployment.devmode.HttpRemoteDevClient$Session.run(HttpRemoteDevClient.java:222)
        at java.base/java.lang.Thread.run(Thread.java:1447)

The URL seems to be based on: <quarkus.live-reload.url>/dev

In the first SSH session, in order to print the logs for a container in a pod, I used the following command on the Linux Command Prompt:
_{[https://kubernetes.io/docs/reference/kubectl/generated/kubectl_logs/]}

kubectl logs -n nl-amis-development kubernetes-quickstart-8579c4797d-5bc2b

With the following output:

2025-11-06 15:16:50,189 INFO  [io.qua.dep.dev.RuntimeUpdatesProcessor] (vert.x-worker-thread-5) Restarting quarkus due to changes in GreetingResource.class.
2025-11-06 15:16:50,191 INFO  [io.quarkus] (Quarkus Main Thread) kubernetes-quickstart stopped in 0.001s
2025-11-06 15:16:50,377 WARN  [io.qua.kub.dep.KubernetesProcessor] (build-22) No project was detected, skipping generation of kubernetes manifests!
2025-11-06 15:16:50,425 INFO  [org.tes.DockerClientFactory] (build-14) Testcontainers version: 1.21.3
2025-11-06 15:16:50,429 INFO  [org.tes.doc.DockerMachineClientProviderStrategy] (build-14) docker-machine executable was not found on PATH ([/usr/local/sbin, /usr/local/bin, /usr/sbin, /usr/bin, /sbin, /bin])
2025-11-06 15:16:50,437 ERROR [org.tes.doc.DockerClientProviderStrategy] (build-14) Could not find a valid Docker environment. Please check configuration. Attempted configurations were:
        UnixSocketClientProviderStrategy: failed with exception InvalidConfigurationException (Could not find unix domain socket). Root cause NoSuchFileException (/var/run/docker.sock)
        DockerDesktopClientProviderStrategy: failed with exception NullPointerException (Cannot invoke "java.nio.file.Path.toString()" because the return value of "org.testcontainers.dockerclient.DockerDesktopClientProviderStrategy.getSocketPath()" is null)As no valid configuration was found, execution cannot continue.
See https://java.testcontainers.org/on_failure.html for more details. [Error Occurred After Shutdown]
__  ____  __  _____   ___  __ ____  ______
 --/ __ \/ / / / _ | / _ \/ //_/ / / / __/
 -/ /_/ / /_/ / __ |/ , _/ ,< / /_/ /\ \
--\___\_\____/_/ |_/_/|_/_/|_|\____/___/
2025-11-06 15:16:50,777 INFO  [io.quarkus] (Quarkus Main Thread) kubernetes-quickstart 1.0.0-SNAPSHOT on JVM (powered by Quarkus 3.25.2) started in 0.584s. Listening on: http://0.0.0.0:8080
2025-11-06 15:16:50,779 INFO  [io.quarkus] (Quarkus Main Thread) Profile dev activated. Live Coding activated.
2025-11-06 15:16:50,781 INFO  [io.quarkus] (Quarkus Main Thread) Installed features: [cdi, compose, kubernetes, rest, smallrye-context-propagation, vertx]
2025-11-06 15:16:50,781 INFO  [io.qua.dep.dev.RuntimeUpdatesProcessor] (vert.x-worker-thread-5) Live reload total time: 24.611s
2025-11-06 15:16:50,782 ERROR [io.qua.ver.htt.run.dev.RemoteSyncHandler] (vert.x-worker-thread-4) Connect failed: java.lang.InterruptedException
        at java.base/java.lang.Object.wait0(Native Method)
        at java.base/java.lang.Object.wait(Object.java:366)
        at io.quarkus.vertx.http.runtime.devmode.RemoteSyncHandler$3$1.call(RemoteSyncHandler.java:142)
        at io.quarkus.vertx.http.runtime.devmode.RemoteSyncHandler$3$1.call(RemoteSyncHandler.java:129)
        at io.vertx.core.impl.ContextImpl.lambda$executeBlocking$4(ContextImpl.java:192)
        at io.vertx.core.impl.ContextInternal.dispatch(ContextInternal.java:270)
        at io.vertx.core.impl.ContextImpl$1.execute(ContextImpl.java:221)
        at io.vertx.core.impl.WorkerTask.run(WorkerTask.java:56)
        at io.vertx.core.impl.TaskQueue.run(TaskQueue.java:81)
        at org.jboss.threads.ContextHandler$1.runWith(ContextHandler.java:18)
        at org.jboss.threads.EnhancedQueueExecutor$Task.doRunWith(EnhancedQueueExecutor.java:2651)
        at org.jboss.threads.EnhancedQueueExecutor$Task.run(EnhancedQueueExecutor.java:2630)
        at org.jboss.threads.EnhancedQueueExecutor.runThreadBody(EnhancedQueueExecutor.java:1622)
        at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1589)
        at org.jboss.threads.DelegatingRunnable.run(DelegatingRunnable.java:11)
        at org.jboss.threads.ThreadLocalResettingRunnable.run(ThreadLocalResettingRunnable.java:11)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Thread.java:1583)

Making a second change to the application code

Next, I changed the return value to:
[in bold, I highlighted the changes]

return "Hello from Quarkus REST. Live Coding demo, change B.";

Then, I refreshed the Web Browser on my Windows laptop.

From the second SSH session, I looked at the output on the Linux Command Prompt:

2025-11-06 15:22:34,406 INFO  [io.qua.dep.dev.RuntimeUpdatesProcessor] (Remote dev client thread) Restarting quarkus due to changes in GreetingResource.class.
2025-11-06 15:22:50,855 INFO  [io.qua.dep.QuarkusAugmentor] (Remote dev client thread) Quarkus augmentation completed in 16445ms
2025-11-06 15:22:50,941 INFO  [io.qua.dep.dev.RuntimeUpdatesProcessor] (Remote dev client thread) Live reload total time: 16.748s
2025-11-06 15:22:59,161 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending app/kubernetes-quickstart-1.0.0-SNAPSHOT.jar
2025-11-06 15:22:59,184 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending dev/app/org/acme/GreetingResource.class
2025-11-06 15:22:59,190 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending quarkus-run.jar
2025-11-06 15:22:59,885 ERROR [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Remote dev request failed: java.io.IOException: Server returned HTTP response code: 500 for URL: http://localhost:8090/dev
        at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1699)
        at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1301)
        at io.quarkus.vertx.http.deployment.devmode.HttpRemoteDevClient$Session.run(HttpRemoteDevClient.java:222)
        at java.base/java.lang.Thread.run(Thread.java:1447)

With the following output (after some time):

Again the “Live Coding” was working. Changes to my local file were immediately available in my containerized environment.

In the first SSH session, in order to print the logs for a container in a pod, I used the following command on the Linux Command Prompt:
_{[https://kubernetes.io/docs/reference/kubectl/generated/kubectl_logs/]}

kubectl logs -n nl-amis-development kubernetes-quickstart-8579c4797d-5bc2b

With the following output:

2025-11-06 15:22:59,247 INFO  [io.qua.dep.dev.RuntimeUpdatesProcessor] (vert.x-worker-thread-8) Restarting quarkus due to changes in GreetingResource.class.
2025-11-06 15:22:59,250 INFO  [io.quarkus] (Quarkus Main Thread) kubernetes-quickstart stopped in 0.001s
2025-11-06 15:22:59,469 WARN  [io.qua.kub.dep.KubernetesProcessor] (build-9) No project was detected, skipping generation of kubernetes manifests!
2025-11-06 15:22:59,503 INFO  [org.tes.DockerClientFactory] (build-25) Testcontainers version: 1.21.3
2025-11-06 15:22:59,511 INFO  [org.tes.doc.DockerMachineClientProviderStrategy] (build-25) docker-machine executable was not found on PATH ([/usr/local/sbin, /usr/local/bin, /usr/sbin, /usr/bin, /sbin, /bin])
2025-11-06 15:22:59,511 ERROR [org.tes.doc.DockerClientProviderStrategy] (build-25) Could not find a valid Docker environment. Please check configuration. Attempted configurations were:
        UnixSocketClientProviderStrategy: failed with exception InvalidConfigurationException (Could not find unix domain socket). Root cause NoSuchFileException (/var/run/docker.sock)
        DockerDesktopClientProviderStrategy: failed with exception NullPointerException (Cannot invoke "java.nio.file.Path.toString()" because the return value of "org.testcontainers.dockerclient.DockerDesktopClientProviderStrategy.getSocketPath()" is null)As no valid configuration was found, execution cannot continue.
See https://java.testcontainers.org/on_failure.html for more details. [Error Occurred After Shutdown]
__  ____  __  _____   ___  __ ____  ______
 --/ __ \/ / / / _ | / _ \/ //_/ / / / __/
 -/ /_/ / /_/ / __ |/ , _/ ,< / /_/ /\ \
--\___\_\____/_/ |_/_/|_/_/|_|\____/___/
2025-11-06 15:22:59,877 INFO  [io.quarkus] (Quarkus Main Thread) kubernetes-quickstart 1.0.0-SNAPSHOT on JVM (powered by Quarkus 3.25.2) started in 0.626s. Listening on: http://0.0.0.0:8080
2025-11-06 15:22:59,878 INFO  [io.quarkus] (Quarkus Main Thread) Profile dev activated. Live Coding activated.
2025-11-06 15:22:59,878 INFO  [io.quarkus] (Quarkus Main Thread) Installed features: [cdi, compose, kubernetes, rest, smallrye-context-propagation, vertx]
2025-11-06 15:22:59,879 INFO  [io.qua.dep.dev.RuntimeUpdatesProcessor] (vert.x-worker-thread-8) Live reload total time: 25.688s
2025-11-06 15:22:59,882 ERROR [io.qua.ver.htt.run.dev.RemoteSyncHandler] (vert.x-worker-thread-7) Connect failed: java.lang.InterruptedException
        at java.base/java.lang.Object.wait0(Native Method)
        at java.base/java.lang.Object.wait(Object.java:366)
        at io.quarkus.vertx.http.runtime.devmode.RemoteSyncHandler$3$1.call(RemoteSyncHandler.java:142)
        at io.quarkus.vertx.http.runtime.devmode.RemoteSyncHandler$3$1.call(RemoteSyncHandler.java:129)
        at io.vertx.core.impl.ContextImpl.lambda$executeBlocking$4(ContextImpl.java:192)
        at io.vertx.core.impl.ContextInternal.dispatch(ContextInternal.java:270)
        at io.vertx.core.impl.ContextImpl$1.execute(ContextImpl.java:221)
        at io.vertx.core.impl.WorkerTask.run(WorkerTask.java:56)
        at io.vertx.core.impl.TaskQueue.run(TaskQueue.java:81)
        at org.jboss.threads.ContextHandler$1.runWith(ContextHandler.java:18)
        at org.jboss.threads.EnhancedQueueExecutor$Task.doRunWith(EnhancedQueueExecutor.java:2651)
        at org.jboss.threads.EnhancedQueueExecutor$Task.run(EnhancedQueueExecutor.java:2630)
        at org.jboss.threads.EnhancedQueueExecutor.runThreadBody(EnhancedQueueExecutor.java:1622)
        at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1589)
        at org.jboss.threads.DelegatingRunnable.run(DelegatingRunnable.java:11)
        at org.jboss.threads.ThreadLocalResettingRunnable.run(ThreadLocalResettingRunnable.java:11)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Thread.java:1583)

I did also try some other things, like adding an extra class to my application and making changes to the content of file application.properties. All of these were successfully picked up by the remote dev mode 😊.

Starting a shell to the running container

In the first SSH session, in order to start a shell to the running container, I used the following command on the Linux Command Prompt:

kubectl exec -it --namespace  nl-amis-development kubernetes-quickstart-8579c4797d-5bc2b -- /bin/bash

With the following output:

[default@kubernetes-quickstart-8579c4797d-5bc2b jboss]$ 

Then, in the shell I executed a series of commands, among others, to navigate the directory structure:

pwd

With the following output:

/home/jboss

whoami

With the following output:

default

ls -latr

With the following output:

total 52
drwxr-xr-x 1 root    root 4096 Jan  1  1970 ..
drwxr-xr-x 1 root    root 4096 Jan  1  1970 .
drwxrwxrwx 1 default root 4096 Nov  6 14:30 app
drwxrwxrwx 2 default root 4096 Nov  6 14:30 quarkus
drwxrwxrwx 1 default root 4096 Nov  6 14:30 lib
-rwxrwxrwx 1 default root 5486 Nov  6 14:30 quarkus-app-dependencies.txt
drwxrwxrwx 1 default root 4096 Nov  6 14:33 dev
-rw-rw-rw- 1 default root  722 Nov  6 15:22 quarkus-run.jar

cd app

ls -latr

With the following output:

total 20
drwxr-xr-x 1 root    root 4096 Jan  1  1970 ..
drwxrwxrwx 1 default root 4096 Nov  6 14:30 .
-rw-rw-rw- 1 default root 1304 Nov  6 15:22 kubernetes-quickstart-1.0.0-SNAPSHOT.jar

cd ..
cd quarkus

ls -latr

With the following output:

total 464
drwxr-xr-x 1 root    root   4096 Jan  1  1970 ..
-rw-rw-rw- 1 default root  10120 Nov  6 14:30 transformed-bytecode.jar
-rw-rw-rw- 1 default root 398093 Nov  6 14:30 generated-bytecode.jar
-rw-rw-rw- 1 default root  42144 Nov  6 14:30 quarkus-application.dat
drwxrwxrwx 2 default root   4096 Nov  6 14:30 .
-rw-rw-rw- 1 default root    208 Nov  6 14:30 build-system.properties

cd ..
cd lib

ls -latr

With the following output:

total 40
drwxr-xr-x 1 root    root  4096 Jan  1  1970 ..
drwxrwxrwx 2 default root  4096 Nov  6 14:30 boot
drwxrwxrwx 2 default root 12288 Nov  6 14:30 main
drwxrwxrwx 1 default root  4096 Nov  6 14:30 .
drwxrwxrwx 1 default root  4096 Nov  6 14:30 deployment

cd ..
cd dev

ls -latr

With the following output:

total 16
drwxr-xr-x 1 root    root 4096 Jan  1  1970 ..
drwxrwxrwx 1 default root 4096 Nov  6 14:33 .
drwxr-xr-x 3 default root 4096 Nov  6 14:55 app

cd app

ls -latr

With the following output:

total 16
drwxrwxrwx 1 default root 4096 Nov  6 14:33 ..
drwxr-xr-x 3 default root 4096 Nov  6 14:55 org
-rw-r--r-- 1 default root  778 Nov  6 14:55 application.properties
drwxr-xr-x 3 default root 4096 Nov  6 14:55 .

exit

vagrant@ubuntu2204:/mnt/mysharedfolder/kubernetes-quickstart$

This represents the following shared folder structure on Windows laptop:

C:\My\AMIS\MySharedFolder\kubernetes-quickstart\target\quarkus-app

Later on, in the first SSH, again I started a shell to the running container in the same manner as I did before.

Then, in the shell I executed the following commands:

cd dev/app/org/acme/

ls -latr

With the following output:

total 12
drwxr-xr-x 3 default root 4096 Nov  7 09:44 ..
drwxr-xr-x 2 default root 4096 Nov  7 11:42 .
-rw-r--r-- 1 default root  610 Nov  7 11:43 GreetingResource.class

Next, two more times, I made some changes to my local file, the source code of the GreetingResource class. Followed by a refresh of the Web Browser on my Windows laptop.

In the shell I executed the following command:

ls -latr

With the following output after that first change:

total 12
drwxr-xr-x 3 default root 4096 Nov  7 09:44 ..
drwxr-xr-x 2 default root 4096 Nov  7 11:42 .
-rw-r--r-- 1 default root  610 Nov  7 12:50 GreetingResource.class

ls -latr

This was the corresponding output on the Linux Command Prompt, from the second SSH session:

2025-11-07 12:50:55,804 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending dev/app/org/acme/GreetingResource.class

In the shell I executed the following command:

ls -latr

With the following output after that second change:

total 12
drwxr-xr-x 3 default root 4096 Nov  7 09:44 ..
drwxr-xr-x 2 default root 4096 Nov  7 11:42 .
-rw-r--r-- 1 default root  610 Nov  7 12:53 GreetingResource.class

This was the corresponding output on the Linux Command Prompt, from the second SSH session:

2025-11-07 12:53:07,403 INFO  [io.qua.ver.htt.dep.dev.HttpRemoteDevClient] (Remote dev client thread) Sending dev/app/org/acme/GreetingResource.class

In the shell I executed the following command:

exit

vagrant@ubuntu2204:/mnt/mysharedfolder/kubernetes-quickstart$

This confirmed what was mentioned earlier in this article and stated in the documentation:

The act of refreshing the browser triggers a scan of the workspace, and if any changes are detected the Java files are compiled, and the application is redeployed, then your request is serviced by the redeployed application.
_{[https://quarkus.io/guides/maven-tooling#dev-mode]}

To conclude this article, the “Live Coding” was working. Changes to my local file were immediately available in my containerized environment 😊.

In this article, you can read more about the steps I took to use “Live Coding” and the remote development mode, so that changes made to the local files of my Java application become immediately visible in that deployed Java application that is running in a container on a Kubernetes cluster in my already existing Linux demo environment, including Quarkus and K3s (a lightweight certified Kubernetes distribution) and setup via Vagrant.

Feel free, among my other articles on this subject, to read:

• “Quarkus – Supersonic Subatomic Java, trying out Quarkus guide “Quarkus – Kubernetes extension” (part 1)”, September 27, 2020
  In this article, you can read more about the steps I took, trying out the Quarkus code guide “Quarkus – Kubernetes extension”, and more specific the steps related to using custom labels and annotations.
• “Quarkus – Supersonic Subatomic Java, trying out some Quarkus code guides (part2)”, October 3, 2020
  In this article, you can read more about the steps I took, trying out the Quarkus code guide “Quarkus – Kubernetes extension”, and more specific the steps related to customizing the namespace, the service account name, the number of replicas and the type of service.
• “Quarkus – Supersonic Subatomic Java, trying out Quarkus guide “Quarkus – Kubernetes extension (part 3)”, October 10, 2020
  In this article, you can read more about the steps I took, trying out the Quarkus code guide “Quarkus – Kubernetes extension”, and more specific the steps related the automatic deployment of the generated resources to a target platform, in my case K3s (lightweight certified Kubernetes distribution).