Review PDB for nginx deployment in all Kubernetes clusters
As discovered in https://gitlab.com/gitlab-com/gl-infra/capacity-planning/-/issues/31 currently our PDB for ingress-nginx isn't tuned correctly
NAME MIN AVAILABLE MAX UNAVAILABLE ALLOWED DISRUPTIONS AGE
gitlab-nginx-ingress-controller 2 N/A 21 356d
This means that theoretically it's possible for a cluster to only have 2 ingress-nginx pods available. Seeing as all our web traffic runs through this, this is incredibly risky. We should look at changing this instead to be a maxUnavailable
PDB instead of specifying min available.