Handling a graceful shutdown

With the lifecycle hooks, we mentioned the pre-stop hook that can be defined and enabled, but if you're writing your own code, then you may find it just as easy to respect the SIGTERM signal that Kubernetes uses to tell containers to shut down.

If you aren't familiar with SIGTERM, it is one of the functions that Linux supports from the kernel—a means of sending an interrupt to a running process. The process can listen for these signals, and you can choose how they respond when they are received. There are two signals that you can't ignore and the operating system will enforce, regardless of what you implement: SIGKILL and SIGSTOP. The signal that Kubernetes uses when it wants to shut down a container is SIGTERM.

The kind of events where you will receive this signal aren't just on error or user-invoked deletion, but also when you roll out a code update leveraging the rolling update mechanism that deployment uses. It can also happen if you take advantage of any of...