Change Active Openshift Master Node IP Address

change-active-ocp-master-IP-address

# It's not recommended to change the active running OCP Master nodes IP Properties unless it's really required to be done.
# To do that, please follow below guide :

# 1. Update the DNS server to use new IP for the target master nodes
# 2. Change the node IP Address from "nmcli" or "nmtui", and reboot the server
# 3. Post reboot, the existing will act normally, but somehow, etcd is not in healthy state. Re-add the etcd member will solve
# 4. Check which etcd pods is CLBO 

oc project openshift-etcd
oc get pods -l k8s-app=etcd

# 5. Remote shell to running etcd pods to remove unhealthy member 

oc rsh <name of the etcd-pods>
sh-4.4# etcdctl member list -w table
sh-4.4# etcdctl member remove <name of the etcd member>
sh-4.4# exit

# 6. Patch the etcd/cluster object to modify config overrides

oc patch etcd/cluster --type=merge -p '{"spec": {"unsupportedConfigOverrides": {"useUnsupportedUnsafeNonHANonProductionUnstableEtcd": true}}}'

# 7. Delete existing etcd secrets for that specific pods

oc get secret | grep -i <name of the etcd-pods>
oc delete secret <output of above commands 3x >

# 8. Double check the secret list, make sure it has been recreated

oc get secret | grep -i <name of the etcd-pods>

# 9. Wait for a while, and the new etcd member will join again

oc rsh <name of the etcd-pods>
sh-4.4# etcdctl member list -w table
sh-4.4# exit

# 10. Patch back the etcd/cluster object to original state

oc patch etcd/cluster --type=merge -p '{"spec": {"unsupportedConfigOverrides": null }}'

# Done