Stateful Kubernetes: PostgreSQL/Redis backups, secrets, and upgrades

[OliverA]

I'm deploying a stateful application with a PostgreSQL database and a Redis cache to our new Kubernetes cluster, and I'm struggling to design a robust deployment strategy that handles data persistence, secure secret management, and zero-downtime updates. I've read the official guides, but they feel too generic. For other engineers who have production experience with similar stacks, what specific manifest structures and controllers do you recommend for stateful workloads? How do you manage database backups and restores within the cluster, and what's your approach to configuring network policies and ingress for internal service communication versus external API access? I'm also unsure about the best practices for resource limits and liveness probes for databases.