1.2. Creating infrastructure machine sets
You can create a MachineSet object to host only infrastructure components. You apply specific Kubernetes labels to these machines and then update the infrastructure components to run on only those machines. These infrastructure nodes are not counted toward the total number of subscriptions that are required to run the environment.
1.2.1. OpenShift Container Platform infrastructure components
The following infrastructure workloads do not incur OpenShift Container Platform worker subscriptions:
- Kubernetes and OpenShift Container Platform control plane services that run on masters
- The default router
- The integrated container image registry
- The cluster metrics collection, or monitoring service, including components for monitoring user-defined projects
- Cluster aggregated logging
- Service brokers
- Red Hat Quay
- Red Hat OpenShift Container Storage
- Red Hat Advanced Cluster Manager
Any node that runs any other container, pod, or component is a worker node that your subscription must cover.
1.2.2. Creating default cluster-wide node selectors
You can use default cluster-wide node selectors on pods together with labels on nodes to constrain all pods created in a cluster to specific nodes.
With cluster-wide node selectors, when you create a pod in that cluster, OpenShift Container Platform adds the default node selectors to the pod and schedules the pod on nodes with matching labels.
You configure cluster-wide node selectors by editing the Scheduler Operator custom resource (CR). You add labels to a node, a machine set, or a machine config. Adding the label to the machine set ensures that if the node or machine goes down, new nodes have the label. Labels added to a node or machine config do not persist if the node or machine goes down.
You can add additional key/value pairs to a pod. But you cannot add a different value for a default key.
Procedure
To add a default cluster-wide node selector:
Edit the Scheduler Operator CR to add the default cluster-wide node selectors:
$ oc edit scheduler cluster
Example Scheduler Operator CR with a node selector
apiVersion: config.openshift.io/v1 kind: Scheduler metadata: name: cluster ... spec: defaultNodeSelector: type=user-node,region=east 1 mastersSchedulable: false policy: name: ""- 1
- Add a node selector with the appropriate
<key>:<value>pairs.
After making this change, wait for the pods in the
openshift-kube-apiserverproject to redeploy. This can take several minutes. The default cluster-wide node selector does not take effect until the pods redeploy.Add labels to a node by using a machine set or editing the node directly:
Use a machine set to add labels to nodes managed by the machine set when a node is created:
Run the following command to add labels to a
MachineSetobject:$ oc patch MachineSet <name> --type='json' -p='[{"op":"add","path":"/spec/template/spec/metadata/labels", "value":{"<key>"="<value>","<key>"="<value>"}}]' -n openshift-machine-api 1- 1
- Add a
<key>/<value>pair for each label.
For example:
$ oc patch MachineSet ci-ln-l8nry52-f76d1-hl7m7-worker-c --type='json' -p='[{"op":"add","path":"/spec/template/spec/metadata/labels", "value":{"type":"user-node","region":"east"}}]' -n openshift-machine-apiVerify that the labels are added to the
MachineSetobject by using theoc editcommand:For example:
$ oc edit MachineSet ci-ln-l8nry52-f76d1-hl7m7-worker-c -n openshift-machine-api
Example output
apiVersion: machine.openshift.io/v1beta1 kind: MachineSet metadata: ... spec: ... template: metadata: ... spec: metadata: labels: region: east type: user-nodeRedeploy the nodes associated with that machine set by scaling down to
0and scaling up the nodes:For example:
$ oc scale --replicas=0 MachineSet ci-ln-l8nry52-f76d1-hl7m7-worker-c -n openshift-machine-api
$ oc scale --replicas=1 MachineSet ci-ln-l8nry52-f76d1-hl7m7-worker-c -n openshift-machine-api
When the nodes are ready and available, verify that the label is added to the nodes by using the
oc getcommand:$ oc get nodes -l <key>=<value>
For example:
$ oc get nodes -l type=user-node
Example output
NAME STATUS ROLES AGE VERSION ci-ln-l8nry52-f76d1-hl7m7-worker-c-vmqzp Ready worker 61s v1.18.3+002a51f
Add labels directly to a node:
Edit the
Nodeobject for the node:$ oc label nodes <name> <key>=<value>
For example, to label a node:
$ oc label nodes ci-ln-l8nry52-f76d1-hl7m7-worker-b-tgq49 type=user-node region=east
Verify that the labels are added to the node using the
oc getcommand:$ oc get nodes -l <key>=<value>,<key>=<value>
For example:
$ oc get nodes -l type=user-node,region=east
Example output
NAME STATUS ROLES AGE VERSION ci-ln-l8nry52-f76d1-hl7m7-worker-b-tgq49 Ready worker 17m v1.18.3+002a51f
