Creating ExternalIPs in OpenShift with MetalLB

Introduction Since the 3.0 release of OpenShift it has come with what is called the OpenShift Routes. This can be thought of as a Layer 7 load balancer for TLS or HTTP applications in your cluster. This layer 7 load balancer works great for web applications and services that use HTTP, HTTPS using SNI, or TLS using SNI. However not all applications are HTTP-based, and some will use protocols other than TCP such as UDP and even SCTP.

May 11, 2022

Understanding OpenShift MachineConfigs and MachineConfigPools

Introduction OpenShift 4 is built upon Red Hat CoreOS (RHCOS), and RHCOS is managed differently than most traditional Operating Systems. Unlike other Kubernetes distributions where you must manage the base Operating System as well as your Kubernetes distribution, with OpenSHift 4 the RHCOS Operating System and the Kubernetes platform are tightly coupled, and management of RHCOS including any system-level configurations is managed by MachineConfigs, and MachineConfigPools. These constructs allow you to manage system configuration and detect configuration drift on your Control Plane and Worker nodes.

April 6, 2022

Using Citrix Netscaler with OpenShift

Introduction The OpenShift platform is a “batteries included” distribution of Kubernetes. It comes with EVERYTHING you need to run a Kubernetes platform from a developer and sysadmin-friendly UI, to monitoring, alerting, platform configuration, and ingress networking. OpenShift was one of the first Kubernetes distributions to realize that having a Kubernetes platform that solved how to load-balance incoming requests for applications was important. OpenShift achieved this through the use of “Routes”. Upstream in Kubernetes this need has been implemented through the use of Ingress, and more recently Gateway API.

March 15, 2022

Using Podman on Mac OSX

Over five years ago I bought an Apple MacBook Pro to learn Go and deep dive into things like containers and Kubernetes. My reasoning was simple, OSX was “*nix” like, the keyboard was amazing, and I could use Docker Desktop to run and manage containers on this machine. I could have used a Windows machine or built a Linux machine, but I wanted the ease of use of Mac, without having to worry about the constant hassles of patching (Windows) or limitations on drivers and power management (Linux).

February 23, 2022

Creating a Mutating Webhook in OpenShift

If you have ever used tools like Istio, or OpenShift Service Mesh, you may have noticed that they have an ability to modify your Kubernetes deployments automatically injecting “side-cars” into your application definitions. Or perhaps you have come across tools that add certificates to your deployment, or add special environment variables to your definitions. This magic is brought to you by Kubernetes Admission Controllers. There are multiple types of admission controllers, but today we will focus on just one of them, “Mutating Webhooks”.

January 13, 2022

Recovering an OCP/OKD Cluster After a Long Time Powered Off

Introduction If you are like me, you have multiple Lab clusters of OpenShift or OKD in your home or work Lab. Each of these clusters takes up a significant amount of resources and so you may shut them down to save power or compute resources. Or perhaps you are running a cluster in one of the many supported Cloud providers, and you power the machines down to save costs when you are not using them.