Kubernetes

Kubernetes is deprecating Docker as a container runtime after v1.20. Don’t Panic 😱 Docker containers are still supported, but the dockershim/Docker, the layer between Kubernetes and containerd is deprecated and will be removed from version 1.22+. https://kubernetes.io/blog/2020/12/02/dont-panic-kubernetes-and-docker/" So if you are running docker you need to change to a supported container runtime interface (CRI). containerd is a good choice, it is already running on your Kubernetes node if you are running Docker. ...

Running a web server in Kubernetes is easy, but a mail server is more challenging. Most of the challenges have to do with your IP infrastructure, ingress, and load balancer within Kubernetes. Here are things I learned when deploying a mail server based on Postfix on Kubernetes with MetalLB and NGINX ingress. If you have a different setup, things might or might not apply. Prevent mail loops on your secondary MX Your Postfix MX pod is maybe running on a private IP RFC1918, which is fine. But Postfix needs to know its public IP to prevent mail looping if your primary MX is down. You need to define your public incoming IP in the main.cf. So, if you use load balancing, you need to define the public IP for the LoadBalancer that would be the same IP as defined in your DNS MX record, not your outgoing IP. ...

This is a simple minimal but highly configurable Varnish caching service for Kubernetes. This should be placed between your ingress and your application service. simple setup It can be used in combination with multiple ingresses and application services at the same time. multiple ingress and services Setup Apply the following yaml file, replicas and environment variables can be adjusted to your need. This will deploy the Varnish service and Varnish proxy pods. The container is now based up on Alpine Linux and Varnish 6.4 ...