ingress-nginx 1.12 & allow-snippet-annotations
If you need to use snippet annotations (why?) on ingress-nginx - you'll also need to adjust the annotation filtering.
multus - deadlock state on thick plugin
Using Multus CNI's 'thick plugin' in Kubernetes can cause pod startup deadlocks due to circular dependencies between pods and the Multus daemon. Switching to the daemonless 'thin plugin' mode effectively resolves this initialization issue.

kubernetes, cgroups v2 and failing health probes
Running Kubernetes on a systemd-based OS can lead to pods restarting endlessly due to health probe failures, caused by the systemd cgroup driver. Previously, this was fixed by modifying boot options, but a simpler approach is to switch the kubelet to use cgroupfs instead.
Can't delete kubernetes namespace (NamespaceDeletionDiscoveryFailure)
While trying to delete a namespace on a kubernetes cluster I learned that there is a resource type apiservice :-) This post shows how to unblock deletions due orphaned apiservice definitions.
mysql - online index creation
This post shows how easy it is to alter tables (in this example index creation) online to keep your sql database uninterrupted and clients online.
Ansible - pretty print output
Sometimes you want to print more or extensive information on ansible output (in this case a terraform plan). This can easily be realised using an stdout callback.
Object attribute defaults on terraform - hello simplicity
Using terraform's object attributes defaults empowers you to create complex input values that still apply default values on a highly granular level. This post shows an example how to use this.
Configurable default values on terraform objects
Creating complex configurations requires many dimensions on the input - this post shows how to take care of default values in such a case to offer users of your code fine grained control without enforcing too much input if not required.