Getting Started on Monitoring with Prometheus and Grafana

Lucas Jellema

Monitoring sounds like a terribly useful thing to do. And in many situations it is of course. However, rather than starting our discussion with monitoring, we really should start from the reasons for considering monitoring. With regard to IT, we typically are faced with non-functional requirements regarding business applications. The […]

Generic Docker container image for running and dynamically reloading an Oracle JET application from a Git repository

Lucas Jellema

This article introduces a Docker Container Image that runs an Oracle JET application from a Git repository and is capable of dynamic reload of that application when the repository contents get updated. The container image sources are on GitHub in repository https://github.com/lucasjellema/docker-oracle-jet-run-live-reload. It has been pushed to Docker Hub as […]

First Steps with Prometheus and Grafana on Kubernetes on Windows

Lucas Jellema 1

Preparation: before I started with Prometheus, I installed VirtualBox, Minikube with Tiller on my Windows 10 laptop – as described in this article: https://technology.amis.nl/2018/08/13/running-kubernetes-1-10-using-minikube-on-windows-10-adding-kubectl-and-helm-tiller/. I then increased the Base Memory setting for the minikube vm to 8192 MB (the default 2048 MB is not sufficient) After making this change – […]

Running Kubernetes 1.10 using MiniKube on Windows 10 (adding kubectl and helm/tiller)

Lucas Jellema 1

Some quick steps to get Minikube for K8S 1.10 up and running on Windows 10 (presuming VirtualBox has already been installed) Download kubectl binary from: https://storage.googleapis.com/kubernetes-release/release/v1.11.0/bin/windows/amd64/kubectl.exe  Copy kubectl.exe to any directory of your liking; add that directory to the PATH environment variable. Download minikube from https://github.com/kubernetes/minikube/releases  Download the minikube-windows-amd64.exe file, […]

Another Taste of India– ODevCYatra 2018

Lucas Jellema

July 2018 saw another edition of the Oracle Developers’ tour through India, called Yatra. In just over two weeks, seven cities participated in this tour – with each city hosting a one day mini-conference (three of four parallel tracks). Organized by many volunteers from the local chapters of the All […]

Running Istio on Oracle Kubernetes Engine–the managed Kubernetes Cloud Service

Lucas Jellema

In a recent post, I introduced the managed Oracle Cloud Service for Kubernetes, the Oracle Kubernetes Engine (OKE): https://technology.amis.nl/2018/05/25/first-steps-with-oracle-kubernetes-engine-the-managed-kubernetes-cloud-service/. A logical next step when working with Kubernetes in somewhat challenging situations, for example with microservice style architectures and deployments, is the use of Istio – to configure, monitor and manage […]

First steps with Oracle Kubernetes Engine–the managed Kubernetes Cloud Service

Lucas Jellema 2

Oracle recently (May 2018) launched its Managed Kubernetes Cloud Service (OKE – Oracle Kubernetes Engine) – see for example this announcement: https://blogs.oracle.com/developers/kubecon-europe-2018-oracle-open-serverless-standards-fn-project-and-kubernetes. Yesterday I got my self a new free cloud trial on the Oracle Public Cloud (https://cloud.oracle.com/tryit). Subsequently, I created a Kubernetes cluster and deployed my first pod on […]

Get going with KSQL on Kubernetes

This article describes how to quickly get going with KSQL on Kubernetes. KSQL is Confuent’s ‘continuous streaming query language’. It allows us to write SQL-like queries that operate on Kafka Topics. Queries that join, filter and aggregate – for each event that gets produced and over time windows. Results are […]

Introducing Elastic Search NoSQL to Oracle SQL developers – comparing dozens of ElasticSearch and SQL operations (a bit like Rosetta)

Lucas Jellema

Even for organizations with strong roots in relational databases such as Oracle RDBMS, there may be valuable opportunities for leveraging additional data sources, for example to support special (search) use cases. Elastic Search (Index) is one of those data stores that can add value – for example to provide powerfur […]

Handle HTTP PATCH request with Java Servlet

Lucas Jellema

The Java Servlet specification does not include handling a PATCH request. That means that class  javax.servlet.http.HttpServlet does not have a doPatch() method, unlike doGet, doPost, doPut etc. That does not mean that a Java Servlet can not handle PATCH requests. It is quite simple to make it do that. The […]

Implementing Authentication for REST API calls from JET Applications embedded in ADF or WebCenter Portal using JSON Web Token (JWT)

Lucas Jellema 1

The situation discussed in this article is as follows: a rich client web application (JavaScript based, could be created with Oracle JET or based on Angular/Vue/React/Ember/…) is embedded in an ADF or WebCenter Portal application. Users are authenticated in that application through a regular login procedure that leverages the OPSS […]