https://kubernetes.slack.com/archives/C4NV3DWUC/p1618579222346800 https://kubernetes.slack.com/archives/C4NV3DWUC/p1612299155160000
kubectl get validatingwebhookconfigurations cert-manager-webhook -ojsonpath='{.webhooks[0].clientConfig.caBundle}' | base64 -d | openssl x509 -noout -text
openssl s_client -connect cert-manager-webhook.cert-manager:443 2> /dev/null | openssl x509 -noout -dates