Renew Expired ETCD Certificater for OCP 4.8 Below

renew-etcd-certs-manually

Red Hat Internal KB : 
https://access.redhat.com/solutions/7023254?band=se&seSessionId=522ca7b0-a002-43d3-a5d2-9a7e387186c0&seSource=Recommendation&seResourceOriginID=09abffc5-23dc-465e-a013-9e52e91306cf

Openshift 4.8 below doesn't have auto rotation for etcd certificate and it will be expired within 3 years

High Level steps :
1) Copy etcd-signer and etcd-metric-signer CA from etcd DB to some folder, create the crt and key file for each signer
2) Backup all manifests for static pods in each master
3) Backup all existing etcd certificates inside /etc/kubernetes/static-pod-resources/etcd-certs/secrets/
4) Create new folder inside above folder ie. call as "all-certs", copy all certificate inside secrets folder to the "all-certs" folder
5) Put the signer crt and key file to that folder, and create the renew-certificate.sh 
6) Execute the shell file, and it will create new_certificates folder
7) Check the expiry date inside the certs, make sure it has been renewed
8) Distribute the cert based on the folder, remove old cert in the "secrets" folder
9) Reboot the nodes