OpenShift Virtualization and Networking Exploration

Table of Contents

• Demos
• Installing OpenShift Virtualization
• Networking
  • Multus General
  • Configure Hypervisor Node Networking
  • Configure Namespace Networking
• High Availability
  • Node Maintenance Operator
  • Node Health Check Operator
• Migration from VMware
• References

Demos

• Affinity and Anti-Affinity

• Cloud-Init application in different ways

• VGT

• VMs with Firewall using overlay networks

Installing OpenShift Virtualization

We’ll reuse the code from the GitOps catalog to install the operator, and then provide our own Hyperconverged resource to instantiate, or configure, the operator.

Install and instantiate the operator from virtualization/

oc apply -k virtualization/operator/base
oc apply -k virtualization/instance/base

Networking

See Networking

Multus General

demo-cni

Configure Hypervisor Node Networking

An OpenShift Template can be used to make the writing of NNCPs a bit more repeatable and fault tolerant. As with most things in life, being organized and consistent is very important in networking. Please don’t write a one-off NNCP. Nothing (very little) is ever "one-off".

Template to create a node network configuration policy.

Some generated NNCPs can be found here networking/components and here.

Because it is common to have different cluster Nodes allocated for different workloads, this template uses NODE_SELECTOR_KEY and NODE_SELECTOR_VALUE parameters to target the nodes which are expected to provide networking for virtual machines. This example uses the machineset used to provision the hypervisor nodes.

Configure Namespace Networking

Attachment to a network is gated by a namespace scoped NetworkAttachmentDefinition resource used by Multus via annotations on pods.

Network attachment definitions in the 'default' namespace are visible to all other namespaces by default. As a cluster administrator you may wish to restrict access by defining attachments in specific user namespaces. Because only an admin may create the NAD it may make sense to place them all in 'default'.

Templates

• Template to create a CNV-Bridge network attachment definition

• Template to create a localnet CNI plugin network attachment definition

Associating a network to an ovs-bridge requires a mapping defined via an NNCP. The template above creates a NNCP and a NAD for each VLAN.

Take a peek at this networking diagram for a sense of how the NNCP and NAD will fit together.

High Availability

Node Maintenance Operator

Node Maintenance Operator

apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  creationTimestamp: "2023-02-07T16:41:54Z"
  generation: 1
  labels:
    operators.coreos.com/node-maintenance-operator.openshift-operators: ""
  name: node-maintenance-operator
  namespace: openshift-operators
spec:
  channel: stable
  installPlanApproval: Automatic
  name: node-maintenance-operator
  source: redhat-operators
  sourceNamespace: openshift-marketplace
---
# necessary?
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
  name: node-maintenance-operator
  namespace: openshift-operators

Create a maintenance and VM live migrated great

Node Health Check Operator

Node Health Check Operator

https://cloud.redhat.com/blog/keeping-virtual-machines-available-by-allowing-nodes-to-self-repair

And Self Node Remediation Operator

• create a NHC

apiVersion: remediation.medik8s.io/v1alpha1
kind: NodeHealthCheck
metadata:
  name: cnv-nodehealthcheck
spec:
  minHealthy: 51%
  remediationTemplate:
    apiVersion: self-node-remediation.medik8s.io/v1alpha1
    kind: SelfNodeRemediationTemplate
    name: self-node-remediation-resource-deletion-template
    namespace: openshift-operators
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-machineset: hub-q4jtr-cnv
  unhealthyConditions:
    #- duration: 60s
    - duration: 300s
      status: 'False'
      type: Ready
    - duration: 300s
      status: Unknown
      type: Ready

Migration from VMware

Details on migration from VMware to OpenShift Virtualization.

References

• OpenShift and OVN Deck

• GUI Free Life

• https://github.com/openshift/network-tools/blob/master/docs/user.md

• How to create VLAN interface for VMs in OpenShift Virtualization? - When using Linux Bridge as opposed to OVS Bridge