Chapter 4. Modifying a compute machine set
You can modify a compute machine set, such as adding labels, changing the instance type, or changing block storage.
If you need to scale a compute machine set without making other changes, see Manually scaling a compute machine set.
4.1. Modifying a compute machine set by using the CLI
You can modify the configuration of a compute machine set, and then propagate the changes to the machines in your cluster by using the CLI.
By updating the compute machine set configuration, you can enable features or change the properties of the machines it creates. When you modify a compute machine set, your changes only apply to compute machines that are created after you save the updated MachineSet custom resource (CR). The changes do not affect existing machines.
Changes made in the underlying cloud provider are not reflected in the Machine or MachineSet CRs. To adjust instance configuration in cluster-managed infrastructure, use the cluster-side resources.
You can replace the existing machines with new ones that reflect the updated configuration by scaling the compute machine set to create twice the number of replicas and then scaling it down to the original number of replicas.
If you need to scale a compute machine set without making other changes, you do not need to delete the machines.
By default, the OpenShift Container Platform router pods are deployed on compute machines. Because the router is required to access some cluster resources, including the web console, do not scale the compute machine set to 0 unless you first relocate the router pods.
The output examples in this procedure use the values for an AWS cluster.
Prerequisites
- Your OpenShift Container Platform cluster uses the Machine API.
-
You are logged in to the cluster as an administrator by using the OpenShift CLI (
oc).
Procedure
List the compute machine sets in your cluster by running the following command:
$ oc get machinesets.machine.openshift.io -n openshift-machine-api
Example output
NAME DESIRED CURRENT READY AVAILABLE AGE <compute_machine_set_name_1> 1 1 1 1 55m <compute_machine_set_name_2> 1 1 1 1 55m
Edit a compute machine set by running the following command:
$ oc edit machinesets.machine.openshift.io <machine_set_name> \ -n openshift-machine-api
Note the value of the
spec.replicasfield, because you need it when scaling the machine set to apply the changes.apiVersion: machine.openshift.io/v1beta1 kind: MachineSet metadata: name: <machine_set_name> namespace: openshift-machine-api spec: replicas: 2 1 # ...- 1
- The examples in this procedure show a compute machine set that has a
replicasvalue of2.
- Update the compute machine set CR with the configuration options that you want and save your changes.
List the machines that are managed by the updated compute machine set by running the following command:
$ oc get machines.machine.openshift.io \ -n openshift-machine-api \ -l machine.openshift.io/cluster-api-machineset=<machine_set_name>
Example output for an AWS cluster
NAME PHASE TYPE REGION ZONE AGE <machine_name_original_1> Running m6i.xlarge us-west-1 us-west-1a 4h <machine_name_original_2> Running m6i.xlarge us-west-1 us-west-1a 4h
For each machine that is managed by the updated compute machine set, set the
deleteannotation by running the following command:$ oc annotate machine.machine.openshift.io/<machine_name_original_1> \ -n openshift-machine-api \ machine.openshift.io/delete-machine="true"
To create replacement machines with the new configuration, scale the compute machine set to twice the number of replicas by running the following command:
$ oc scale --replicas=4 \1 machineset.machine.openshift.io <machine_set_name> \ -n openshift-machine-api- 1
- The original example value of
2is doubled to4.
List the machines that are managed by the updated compute machine set by running the following command:
$ oc get machines.machine.openshift.io \ -n openshift-machine-api \ -l machine.openshift.io/cluster-api-machineset=<machine_set_name>
Example output for an AWS cluster
NAME PHASE TYPE REGION ZONE AGE <machine_name_original_1> Running m6i.xlarge us-west-1 us-west-1a 4h <machine_name_original_2> Running m6i.xlarge us-west-1 us-west-1a 4h <machine_name_updated_1> Provisioned m6i.xlarge us-west-1 us-west-1a 55s <machine_name_updated_2> Provisioning m6i.xlarge us-west-1 us-west-1a 55s
When the new machines are in the
Runningphase, you can scale the compute machine set to the original number of replicas.To remove the machines that were created with the old configuration, scale the compute machine set to the original number of replicas by running the following command:
$ oc scale --replicas=2 \1 machineset.machine.openshift.io <machine_set_name> \ -n openshift-machine-api- 1
- The original example value of
2.
Verification
To verify that a machine created by the updated machine set has the correct configuration, examine the relevant fields in the CR for one of the new machines by running the following command:
$ oc describe machine.machine.openshift.io <machine_name_updated_1> \ -n openshift-machine-api
To verify that the compute machines without the updated configuration are deleted, list the machines that are managed by the updated compute machine set by running the following command:
$ oc get machines.machine.openshift.io \ -n openshift-machine-api \ -l machine.openshift.io/cluster-api-machineset=<machine_set_name>
Example output while deletion is in progress for an AWS cluster
NAME PHASE TYPE REGION ZONE AGE <machine_name_original_1> Deleting m6i.xlarge us-west-1 us-west-1a 4h <machine_name_original_2> Deleting m6i.xlarge us-west-1 us-west-1a 4h <machine_name_updated_1> Running m6i.xlarge us-west-1 us-west-1a 5m41s <machine_name_updated_2> Running m6i.xlarge us-west-1 us-west-1a 5m41s
Example output when deletion is complete for an AWS cluster
NAME PHASE TYPE REGION ZONE AGE <machine_name_updated_1> Running m6i.xlarge us-west-1 us-west-1a 6m30s <machine_name_updated_2> Running m6i.xlarge us-west-1 us-west-1a 6m30s
