Introduction Some time ago, I wrote about the new preview feature in Azure Automation Accounts to use Managed Identities [1]. I think that it is useful to migrate to this new feature as soon as possible: managed identities are used in many places in Azure and it is better to […]
Platform Technology
VNet peering in Azure
Introduction I looked into virtual network peering peering in Azure and I saw something that looked rather strange to me. Let me explain what it was, how VNet peering works and what you should be aware of from a security perspective. Situation I have two virtual networks: one for 10.1.0.0/16 […]
Using one-time upload URLs in AWS with S3 versioning
In this blog, I will show how you can use the SAM (Serverless Application Model) to get a presigned upload URL to AWS S3 that can be used exactly once [1]. In AWS it is possible to use a presigned URL to upload files, but the URL is valid for […]
Using one-time upload URLs in AWS with Memcached
In this blog I will show how you can use the SAM (Serverless Application Model) to get a presigned upload URL to AWS S3 that can be used exactly once [1]. In AWS it is possible to use a presigned URL to upload files, but the URL is valid for […]
Using one-time upload URLs in AWS using DynamoDB
In this blog, I will show how you can use the SAM (Serverless Application Model) to get a presigned upload URL to AWS S3 that can be used exactly once [1]. In AWS it is possible to use a presigned URL to upload files where the URL is valid for […]
AWS Lambda: shared libraries (and SAM)
In June I wrote a blog series about the AWS Shop Example. In this series, I also wrote about X-Ray [1]. I like X-Ray: you can see how much time each step in a whole concattenation of AWS services takes and how much time it costs to send the response […]
AWS blog series part 6: speed up the use of the ELB Health Status
It took me a while, but then this blog series was ready: five blog articles about Windows Failover Clustering and Auto Scaling Groups with one node. I was happy, but then a thought was nagging me. Let me explain the problem by showing you the results for the Auto Scaling […]
AWS blog series part 5: Start PowerShell script after a reboot when Windows fails to do so
You might have wondered in the second blog of this series [1], why I mentioned the possibility that the Task Scheduler didn’t start after a reboot in the “on-premise” (Hyper-V) environment, but I didn’t do so in the AWS environment. Well, that’s because I used a “trick”, where AWS will […]
Windows Failover Cluster on AWS part 4: Construction of the CloudFormation scripts
Introduction If you follow along in this blog series [1], I can imagine that if you deployed the CloudFormation scripts, that you think “wow, how does it work”. In this blog, I try to answer that question. 1. Windows Failover Clustering Nested stacks When you start the CloudFormationFailover.yml script, you […]
AWS Migration part 1: how to migrate Windows Failover Clustering servers to AWS?
Introduction In this series, I will look at the migration from on-premise Windows Failover Clusters to AWS. What is the difference in recovery times between the application on-premise, the 1:1 migration of a Failover Cluster to AWS and the commonly used pattern of an Auto Scaling Group with one node? […]
How to dynamically Schedule EM Blackouts after PatchTuesday
In the organization I’m currently working for, the OS-patch schedule depends on PatchTuesday (PT) just as Microsoft, Adobe or Oracle are using. And PatchTuesday is, as you all know, the Second Tuesday of each month. But this is a schedule you can not set in the Oracle Enterprise Manager Scheduler. […]
Jenkins Pipeline: SonarQube and the OWASP Dependency-Check
The OWASP Foundation plays an important role in helping to improve security of software worldwide. They have created a popular and well-known awareness document called the ‘OWASP Top 10‘. This document lists the following risk: using components with known vulnerabilities. Software nowadays can be quite complex consisting of many direct and […]
Quarkus – Supersonic Subatomic Java, trying out Quarkus guide “Quarkus – Kubernetes extension” (part 3)
In this article, you can read more about the Quarkus code guide I tried out, related to the following topic: The ability to automatically generate Kubernetes resources by Quarkus The guide covers generating and deploying Kubernetes resources based on sane defaults and user supplied configuration. In this article, I will […]
Quarkus – Supersonic Subatomic Java, trying out Quarkus guide “Quarkus – Kubernetes extension” (part 2)
In this article, you can read more about the Quarkus code guide I tried out, related to the following topic: The ability to automatically generate Kubernetes resources by Quarkus The guide covers generating and deploying Kubernetes resources based on sane defaults and user supplied configuration. In this article, I will […]
Quarkus – Supersonic Subatomic Java, trying out Quarkus guide “Quarkus – Kubernetes extension” (part 1)
In this article, you can read more about the Quarkus code guide I tried out, related to the following topic: The ability to automatically generate Kubernetes resources by Quarkus The guide covers generating and deploying Kubernetes resources based on sane defaults and user supplied configuration. In this article, I will […]
Jenkins: Building Java and deploying to Kubernetes
Kubernetes is a popular platform to run and manage containerized applications. A CI/CD solution is often needed but not always provided. You might need to set this up for yourself. In this blog post I’ll provide a minimal end-to-end solution for Java applications. This starts with a commit in source […]
Quarkus – Supersonic Subatomic Java, trying out some Quarkus code guides (part2)
In this article, you can read more about a Quarkus code guide I tried out, related to the following topic: Packaging the native executable in a container In a next article, you can read more about another Quarkus code guide I tried out, related to the following topic: The ability […]
OpenEBS: cStor storage engine on KVM
OpenEBS provides a Kubernetes native distributed storage solution which is friendly on developers and administrators. It is completely open source and part of the CNCF. Previously I wrote about installing and using OpenEBS, Jiva storage engine, on the Charmed Kubernetes distribution of Canonical. The Jiva storage class uses storage inside managed […]
Production-like Kubernetes on your laptop. Kubespray on KVM
There are various options to install a production-like Kubernetes distribution on your laptop. Previously I tried out using the Canonical stack (Juju, MAAS, Charmed Kubernetes) for this. This worked nicely but it gave me the feeling that it was a bit Canonical specific and it felt a bit heavy on resources at […]
AWS Shop example: Amazon X-Ray
Introduction We are in production with our shop example [1]. We’d like to get some statistics about our implementation: how often are the Lambda functions called? How fast are they? Of course, we could use the statistics from the performance test, but there is a faster way. This faster way […]
AWS Shop example: SNS duplicate messages
Introduction Our shop example [1] is now in production, wohoo!!! When you are using our example program in production, you might see that some sales are updated multiple times in the database. This will not happen very often, but you want your sales to be processed once, not twice. In […]
AWS Shop example: step functions
Introduction When you follow along in this series [1], you might have been irritated by the amount of work to test your functions. It isn’t a problem to test only the unit test for the accept function, but when you have to test the unit test for the decrypt function, […]
OpenEBS: Create persistent storage in your Charmed Kubernetes cluster quick and easy!
As a developer I wanted to experiment with Kubernetes environments which approximate production deployments. In order to do that I wanted a distributed storage solution and chose OpenEBS. Mainly because it was easy to get started and quick to get up and running. In this blog post I’ll describe how […]
AWS Shop example: unit tests
Introduction In the last six blogs [1], I showed you an application that used AWS to process the sales from a cashing machine. This series continues with tests for this application. Some objects of our solution cannot be tested: we cannot test the API gateway, the SNS topics or DynamoDB […]
Charmed Kubernetes on KVM using MAAS and Juju
Coming to this solution was a journey. I was looking for a Kubernetes installation which was easy to deploy and cleanup on my own laptop (I didn’t want to have to pay for a hosted solution). I did want a solution which was more or less production-like because I wanted […]
AWS Shop example: the API Gateway (1)
Introduction You might have noticed that we skipped the API Gateway up to now [1]. I will write two blogs about the API Gateway. In this one, we follow the simplest route: from sending the message to the API gateway, and let the API Gateway deliver the message at the […]
Migrating databases using Dataguard, some pitfalls and observations
My customer needed to migrate to a new set of datacenters, and while other services were able to “lift and shift”, the Oracle RAC database servers had to be rebuilt in the new datacenter because the underlying platform wasn’t able to migrate the shared disks. Fortunately the environment was already […]
Windows Sandbox with Chocolatey, Scoop, Git, VisualStudio Code and more
I recently wrote an article to introduce Windows Sandbox. I explained how the Sandbox can have folders mapped from the host, have network interactions with the host (and the rest of the world) and use the clipboard for exchanging objects to and from the host. I also mentioned the logon […]
Quick and easy: A multi-node Kubernetes cluster on CentOS 7 + QEMU/KVM (libvirt)
Kubernetes is a popular container orchestration platform. As a developer understanding the environment in which your application is going to run is important since this can help you use available services of the platform and fix issues. There are several options to run Kubernetes locally to get some experience with […]
Windows Sandbox – light weight playground for R&D, tutorials and workshops
Windows Sandbox to me is a light weight Windows 10 virtual machine that I can quickly start and stop and use to install and run programs. The Windows Sandbox provides a well defined, clean environment that is fresh every time it is started. Inside the Sandbox, I can create an […]
Access OCI OKE Kubernetes Dashboard locally through Cloud Shell Proxy and ngrok
This article tells you how to access the Kubernetes Dashboard on top of an Oracle Cloud Infrastructure OKE Cluster Instance from a browser – without locally installing kubectl. This trick uses OCI Cloud Shell to run kubectl to proxy to the dashboard application running inside the K8S Cluster and it […]
Using PXE to deploy a DNS server
Last week, I published a blog about implementing a PXE server [1]. Today I’ll show how kickstart/anaconda files can be used to deploy a server. I will use the example of a DNS-server to explain what can be changed where in kickstart files and what you can do when the […]
Deploying CentOS 8 using PXE
What is PXE? PXE (Preboot eXecution Environment) is a method of deploying an operating system to a computer over the network. I think it’s great: you don’t need to burn CD’s or DVD’s anymore. The only thing you have to do is changing the boot order in the BIOS, and […]
Linux Shell Script – passing arguments to functions and returning and capturing results
Developing Linux Shell Scripts is just not the same as programming in modern programming language. At least to me, it still feels novel and at times a bit weird. I am currently engaged in some scripting that requires the use of functions. That is all well, but I want to […]
Resolving issue: Oracle Virtual Box and Windows 10 – Call to WHvSetupPartition failed VERR_NEM_VM_CREATE_FAILED
Like so many colleagues and fellow developers around the world, the latest Windows Update also messed up my machine’s ability to successfully run Oracle Virtual Box. When running vagrant to provision a VM, I ran into messages such as: Failed to open a session for the virtual machine. Call to […]
Ultra fast, ultra small Kubernetes on Linux – K3S beating minikube
The easiest way I knew for running a local Kubernetes cluster was minikube. It installs like a breeze and creates a fresh clean cluster with minimal effort on my part. Sure, it takes a while to get going and uses quite a bit of system resources, but it performs quite […]
Switch off Screen Lock on Ubuntu Bionic Desktop
I am running an Ubuntu VM on Virtual Box. A guest running inside a host system. I am getting quite annoyed with Ubuntu locking the screen quite aggressively. Since the host OS probably already runs screensaver and screen lock, I want to switch off the screen lock in the Ubuntu […]
Getting started with Windows Subsystem for Linux, Ubuntu and Docker
Starting with a vanilla Windows 10 environment, it took just a few simple steps to get going with Linux on my Windows machine in the Windows Subsystem for Linux (WSL). Note: this is not yet Version 2 of wsl which is currently in (limited) preview install Ubuntu App from Windows […]
Upgrade Failure as Blessing in Disguise?
or The Findings of an Failed Enterprise Manager Upgrade to OEM13.3 When Oracle Enterprise Manager Cloud Control 13.3 (here just called EM 13.3) came available I read the upgrade documentation and decided that the most cost-effective option for us was to stay with EM 13.2. Later, a rumor about a […]
Graceful shutdown of forked workers in Python and JavaScript running in Docker containers
You might encounter a situation where you want to fork a script during execution. For example if the amount of forks is dependent on user input or another specific situation. I encountered such a situation in which I wanted to put load on a service using multiple concurrent processes. In […]