Extending Istio Self-Signed Root Certificate Lifetime
Istio self-signed certificates have historically had a 1 year default lifetime. If you are using Istio self-signed certificates, you need to schedule regular root transitions before they expire. An expiration of a root certificate may lead to an unexpected cluster-wide outage. The issue affects new clusters created with versions up to 1.0.7 and 1.1.7.
See Extending Self-Signed Certificate Lifetime for information on how to gauge the age of your certificates and how to perform rotation.