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Fedora Infra OCP4 Tech Talk #fedora-meeting-3 2022-01-20 16:00 UTC
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ocp4_talk.md

Fedora Infra - Tech Talk - Openshift 4

David Kirwan

a quick overview

Fedora Infra

We recently deployed a new Openshift 4 cluster on a mix of VMs (Control Plane) and Baremetal (Workers). Most are aware already I'm sure, but just in case you are not, we currently run Openshift 3 in production. Our intention is to migrate all our applications over to this new cluster in the coming months. You can login to the clusters with your Noggin/IPA usernames, but by default you won't have the ability to run any workloads.

We are working behind the scenes to get access to an Openshift cluster on which the community may run containers etc, but no estimate as to when this will be available.

  • Fedora Infra OCP 4 Cluster Console 1
  • Fedora Infra OCP 4 Cluster Staging Console 2

OCP4 Components

I'll give a quick overview of the new/interesting features that are now available to us in Openshift 4 1, this is not an exhaustive list:

  • Much is the same but there are some interesting differences.
  • Openshift 4 includes many new technologies and features, one example is the support for Operators.
  • RHEL CoreOS is the operating system which Openshift 4 runs on top of.
  • OCP4 self manages the RHCOS machines it runs on top of.
  • Any customisations are made via MachineConfig Pre install configurations and Post-install configurations.
  • Workloads can expose monitoring metrics and even set alerts based on these via User Workload Monitoring Stack which is enabled. I gave a talk on this recently see 5 for more information.

Operators

Lets talk about the first big change. What is an operator? Well.. it's a Custom Resource Controller. Emphasis on custom.

  • If you are familiar with Kubernetes, without realising it you will already know what a Resource Controller is.
  • Resource Controllers are the system logic which manages Kubernetes API object types eg: (Pod, Deployment, PersistentVolume, PersistentVolumeClaim etc).
  • Custom Resource Controllers extend the Kubernetes API, and allow us to add new features.
  • We have a framework/sdk which we can use to build and develop these operators, following the Operator Pattern2.
  • OCP4 has a catalog from which Operators maybe downloaded and installed.

Operators We have Installed

Some of the operators we have installed are:

  • Openshift Virtualisation (KubeVirt, kvm) 1
  • Local Storage Operator (Exposes the local disk storage on nodes as PersistentVolumes) 2
  • Openshift Data Foundation (Renamed in OCP4.9 from Openshift Container Storage, Ceph) 3

Fin!

Any questions?

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