2.1 Infrastructure nodes

Not exactly a day 2-operations task, but one that immensily simplifies operations. The concept of infrastructure nodes was more prominently advertised by Red Hat when OpenShift 3 was the latest and greatest. This evidently changed somehow for OpenShift 4, but with a bit of legwork we’re able to create those, too.

Infra nodes are dedicated worker nodes intended for infrastructure components such as the image registry, routers or the whole monitoring stack. Providing dedicated nodes helps ensuring that there’s always enough resources for infrastructure components.

Task 2.1.1: Create a machine set

The best way to add infra nodes to the cluster is via machine sets. Machine sets are usually only supported on clusters installed with the IPI installation method. They could be compared to deployments: If deployments are responsible for creating replica sets and ultimately pods, machine sets create machines to then add them as nodes to the cluster.

Probably the easiest way to create a machine set for infra nodes is to copy and adapt the existing worker MachineSet in the openshift-machine-api namespace.

First of all, get the yaml definition of the existing worker MachineSet resource inside the openshift-machine-api namespace.

Hints

Check the name of the existing worker MachineSet resource inside the openshift-machine-api namespace:

oc get machinesets -n openshift-machine-api

Using this information, write the existing worker MachineSet resource into a file:

oc get machinesets -n openshift-machine-api -o yaml <machineset name> > machineset_infra.yaml

Now, adapt the file so its content describes an infra MachineSet.

Warning

By far not all occurrences of worker must be changed into infra.

Refer to the documentation if you are not sure what to replace.

Hints

Edit the file using your favorite editor (still vim of course):

Remove all the unnecessary clutter such as the .metadata.managedFields part or creationTimestamp fields
Replace all occurrences of worker with infra except for everything under providerSpec
Ensure that replicas is set to 3
Add the infra role label to the .spec.template.spec.metadata.labels field like so:

    spec:
      metadata:
        creationTimestamp: null
        labels:
          node-role.kubernetes.io/infra: ""
      providerSpec:

When you’re finished, your MachineSet resource file should look similar to this:

apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  annotations:
    machine.openshift.io/GPU: "0"
    machine.openshift.io/memoryMb: "32768"
    machine.openshift.io/vCPU: "8"
  labels:
    machine.openshift.io/cluster-api-cluster: user01-ops-training-75gjz
  name: user01-ops-training-75gjz-infra-eu-north-1a
  namespace: openshift-machine-api
spec:
  replicas: 3
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: user01-ops-training-75gjz
      machine.openshift.io/cluster-api-machineset: user01-ops-training-75gjz-infra-eu-north-1a
  template:
    metadata:
      labels:
        machine.openshift.io/cluster-api-cluster: user01-ops-training-75gjz
        machine.openshift.io/cluster-api-machine-role: infra
        machine.openshift.io/cluster-api-machine-type: infra
        machine.openshift.io/cluster-api-machineset: user01-ops-training-75gjz-infra-eu-north-1a
    spec:
      metadata:
        creationTimestamp: null
        labels:
          node-role.kubernetes.io/infra: ""
      providerSpec:
        value:
          ami:
            id: ami-0080eb90a48d9655e
          apiVersion: awsproviderconfig.openshift.io/v1beta1
          blockDevices:
          - ebs:
              encrypted: true
              iops: 0
              kmsKey:
                arn: ""
              volumeSize: 120
              volumeType: gp2
          credentialsSecret:
            name: aws-cloud-credentials
          deviceIndex: 0
          iamInstanceProfile:
            id: user01-ops-training-75gjz-worker-profile
          instanceType: m5.2xlarge
          kind: AWSMachineProviderConfig
          metadata:
            creationTimestamp: null
          placement:
            availabilityZone: eu-north-1a
            region: eu-north-1
          securityGroups:
          - filters:
            - name: tag:Name
              values:
              - user01-ops-training-75gjz-worker-sg
          subnet:
            filters:
            - name: tag:Name
              values:
              - user01-ops-training-75gjz-private-eu-north-1a
          tags:
          - name: kubernetes.io/cluster/user01-ops-training-75gjz
            value: owned
          - name: acend-training
            value: ocp4-ops
          - name: customer
            value: acend
          - name: username
            value: user01
          userDataSecret:
            name: worker-user-data

Warning

You cannot use the sample MachineSet resource definition above without further modification. It’s recommended you use your own worker MachineSet definition and make the described changes.

Now, create the MachineSet.

Hints

oc create -f machineset_infra.yaml

Check if the machines were created and that they’re in the Provisioning state:

Hints

oc get machines -n openshift-machine-api

It shouldn’t take too long and you will see new infra nodes popping up.

Last modified May 1, 2026: Merge 13c5f04a7602b63584a607bb4f840408b1830cbd into 51f8206716f9645f6b09fc31ff5c56df56f7109b (df66222)