manage_servers

Manage Servers

Here are various notes specific to master/node management in no paticular order

• Masters
• Nodes

Masters

Sometimes, in order to deploy pods on them, you'll need to mark your masters schedulable

root@master# oc adm manage-node ose3-master.example.com --schedulable=true

In 4.2 nightly builds, the masters are schedulable by default;mark them as unschedulable by first running

oc edit schedulers cluster

Then set masterschedulable to false. Then you can remove the worker label from the master.

Nodes

• Assign Node Roles
• Node Selector

Roles

Label for node roles

oc label node infra1.cloud.chx node-role.kubernetes.io/infra=true

Common roles are...

node-role.kubernetes.io/compute: "true"
node-role.kubernetes.io/infra: "true"
node-role.kubernetes.io/master: "true"

Your nodes will look like this

[root@master1 ~]# oc get nodes
NAME                STATUS    ROLES     AGE       VERSION
app1.cloud.chx      Ready     compute   33d       v1.9.1+a0ce1bc657
app2.cloud.chx      Ready     compute   33d       v1.9.1+a0ce1bc657
app3.cloud.chx      Ready     compute   33d       v1.9.1+a0ce1bc657
cns1.cloud.chx      Ready     compute   33d       v1.9.1+a0ce1bc657
cns2.cloud.chx      Ready     compute   33d       v1.9.1+a0ce1bc657
cns3.cloud.chx      Ready     compute   33d       v1.9.1+a0ce1bc657
infra1.cloud.chx    Ready     infra     33d       v1.9.1+a0ce1bc657
infra2.cloud.chx    Ready     infra     33d       v1.9.1+a0ce1bc657
master1.cloud.chx   Ready     master    33d       v1.9.1+a0ce1bc657
master2.cloud.chx   Ready     master    33d       v1.9.1+a0ce1bc657
master3.cloud.chx   Ready     master    33d       v1.9.1+a0ce1bc657

Node Selector

To deploy an app on a specific node....

oc edit namespace default

and add...

openshift.io/node-selector: region=infra

OR, you can just annotate it.

root@master# oc annotate namespace default openshift.io/node-selector=region=infra

Then make sure your nodeSelector matches the key=value paring.

Adding nodes on OpenShift 4

To get ignition for worker

oc extract -n openshift-machine-api secret/worker-user-data --keys=userData --to=-

To get ignition for master

oc extract -n openshift-machine-api secret/master-user-data --keys=userData --to=-