In this post I will try to explain how to restart your running pods with kubectl.
the old way
Before Kubernetes version 1.15, we mostly had only one choice to restart a deployment that is running and was to sacle down our deployment with
kubectl scale deployment mydeployment --replicas=0 -n mynamespace
followed by an increase in replicas right after:
kubectl scale deployment mydeployment --replicas=1 -n mynamespace
As you can probably deduct from the commands, this involved killing all pods involved, and rescaling them. This frequently lead to downtimes of systems, even if just for seconds and is thus a suboptimal way of restarting your services.
the new and improved solution
Luckily we do not need to do it this way anymore and can make use of the newly integrated way, of rolling out a deployment with:
kubectl -n service rollout restart deployment <mydeployment>
The avid reader will notice right away that instead of scaling our deployment to 0, therefore killing all the replicas and then booting them back up, we are able to use ar rolling rollout, which will restart our pods one by one and therefore will keep our deployment alive. Therefore guaranteeing that at least one of our pods is still available.
Please note though, if you only have one replica activated, using the rolling restart will still only minimize the downtime of your deployment.