How to validate k8s certificates for version 1.12.3?

Question

linux

Hello.

There is a kubernetes cluster of 3 master nodes, 5 work nodes, 3 etcd nodes.
the time has come to update the certificates.
Everything would be fine, but the version of k8s is v1.12.3

, in general, as in 1.15

kubeadm certs check-expiration
, it will not be possible to use it, I

found another option

echo | openssl s_client -showcerts -connect master_node1:6443 -servername api 2>/dev/null | openssl x509 -noout -enddate

will it be enough?

Answer 1

Just checking is enough. It will be more convenient to make a loop:

for DOMAIN in host1.com host2.com host3.com
do
  DOMAIN_EXPIRES=$(echo | openssl s_client -connect $DOMAIN:443 2>/dev/null | openssl x509 -noout -dates | grep notAfter | awk -F= '{print $2}')
  echo $DOMAIN: $DOMAIN_EXPIRES
done