$ oc describe pod router-default-66d5cf9464-7pwkc Name: router-default-66d5cf9464-7pwkc Namespace: openshift-ingress .... Controlled By: ReplicaSet/router-default-66d5cf9464
A node selector specifies a map of key-value pairs. The rules are defined using custom labels on nodes and selectors specified in pods.
For the pod to be eligible to run on a node, the pod must have the indicated key-value pairs as the label on the node.
If you are using node affinity and node selectors in the same pod configuration, see the important considerations below.
You can use node selector labels on pods to control where the pod is scheduled.
With node selectors, OpenShift Container Platform schedules the pods on nodes that contain matching labels.
To add node selectors to an existing pod, add a node selector to the controlling object for that node, such as a ReplicaSet, Daemonset, or StatefulSet. Any existing pods under that controlling object are recreated on a node with a matching label. If you are creating a new pod, you can add the node selector directly to the pod spec.
You can add labels to a node or MachineConfig, but the labels will not persist if the node or machine goes down. Adding the label to the MachineSet ensures that new nodes or machines will have the label.
You cannot add a node selector directly to an existing scheduled pod. |
To add a node selector to existing pods, determine the controlling object for that pod.
For example, the router-default-66d5cf9464-m2g75
pod is controlled by the router-default-66d5cf9464
ReplicaSet:
$ oc describe pod router-default-66d5cf9464-7pwkc Name: router-default-66d5cf9464-7pwkc Namespace: openshift-ingress .... Controlled By: ReplicaSet/router-default-66d5cf9464
The web console lists the controlling object under ownerReferences
in the pod YAML:
ownerReferences: - apiVersion: apps/v1 kind: ReplicaSet name: router-default-66d5cf9464 uid: d81dd094-da26-11e9-a48a-128e7edf0312 controller: true blockOwnerDeletion: true
Add labels to a node by using a MachineSet or editing the node directly:
Use a MachineSet to add labels to nodes managed by the MachineSet when a node is created:
Run the following command to add a node selector to a MachineSet:
$ oc patch MachineSet <name> --type='json' -p='[{"op":"add","path":"/spec/template/spec/metadata/labels", "value":{"<key>"="<value>","<key>"="<value>"}}]' -n openshift-machine-api
For example:
$ oc patch MachineSet abc612-msrtw-worker-us-east-1c --type='json' -p='[{"op":"add","path":"/spec/template/spec/metadata/labels", "value":{"type":"user-node","region":"east"}}]' -n openshift-machine-api
Verify that the label is added to the MachineSet by using the oc edit
command:
For example:
$ oc edit MachineSet abc612-msrtw-worker-us-east-1c -n openshift-machine-api
apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
....
spec:
...
template:
metadata:
...
spec:
metadata:
labels:
region: east
type: user-node
....
Add labels directly to a node:
Edit the Node
object for the node:
$ oc label nodes <name> <key>=<value>
For example, to label a node:
$ oc label nodes ip-10-0-142-25.ec2.internal type=user-node region=east
Verify that the label is added to the node:
$ oc get nodes -l type=user-node,region=east
NAME STATUS ROLES AGE VERSION
ip-10-0-142-25.ec2.internal Ready worker 17m v1.18.3+002a51f
Add the matching node selector a pod:
To add a node selector to existing and future pods, add a node selector to the controlling object for the pods:
kind: ReplicaSet
....
spec:
....
template:
metadata:
creationTimestamp: null
labels:
ingresscontroller.operator.openshift.io/deployment-ingresscontroller: default
pod-template-hash: 66d5cf9464
spec:
nodeSelector:
beta.kubernetes.io/os: linux
node-role.kubernetes.io/worker: ''
type: user-node (1)
1 | Add the node selector. |
To add a node selector to a specific pod, add the selector to the Pod
object directly:
apiVersion: v1
kind: Pod
...
spec:
nodeSelector:
<key>: <value>
...
For example:
apiVersion: v1
kind: Pod
....
spec:
nodeSelector:
region: east
type: user-node