Kubernetes Explained Simply: Waiting For Kubernetes [Part 5]

When you deploy stuff for a living, you find yourself waiting around, a lot. Wait for Terraform to spin up the AWS VPCs. Wait for the Kubernetes cluster node VMs to boot. Wait for the Kubernetes cluster to coalesce. Wait for the CNI pods, DNS pods, and kube-proxy bits to be happy. Wait, wait, wait. feels your pain there, and has some nifty ways of helping you wait (or not!) for the things you deploy or delete to coalesce. kubectl To wait for a single pod to do something, we can use the command, and pause until a condition is met on the pod: wait pod/slow condition met $ kubectl pod/slow -- condition=ready wait for Here's a more rigorous shell session, with bounding so you can better visualize the passage of time: date namespace/trick5 created configmap/opt created pod/slow created Tue Feb 11 10:58:31 EST 2020 NAME READY STATUS RESTARTS AGE slow 0/1 Init:0/1 0 1s pod/slow condition met Tue Feb 11 10:58:39 EST 2020 # ~8s later! NAME READY STATUS RESTARTS AGE slow 1/1 Running 0 9s $ kubectl apply -f trick5/pod.yml $ date $ kubectl get pods $ kubectl pod/slow -- condition=ready wait for $ date $ kubectl get pods (This uses the from the ) pod.yml Silly Kubectl Tricks GitHub repository You'll probably want to wait for either , , or . If you want, you can even define your own , which will delay the condition until your custom gates resolve to true. ready initialized containersReady readiness gates ready You can find out more, . here, in the official Kubernetes documentation Bigger Things Than Pods Chances are you aren't dealing directly with individual pods, but are concerned chiefly with Deployments, StatefulSets, or DaemonSets. For , you can use deployments kubectl rollout status kubectl rollout status deploy/slow Waiting deployment rollout finish: updated replicas are available... Waiting deployment rollout finish: updated replicas are available... Waiting deployment rollout finish: updated replicas are available... Waiting deployment rollout finish: updated replicas are available... Waiting deployment rollout finish: updated replicas are available... deployment successfully rolled for "slow" to 0 of 5 for "slow" to 1 of 5 for "slow" to 2 of 5 for "slow" to 3 of 5 for "slow" to 4 of 5 "slowdep" out This command will block while the entirety of the deployment is incrementally "rolled out" and comes up to a state of readiness. As the pods in the current live replica set spin up. prints helpful progress updates, to keep you abreast of what's happening while you wait. kubectl rollout status This works for . StatefulSets and DaemonSets, too You can also use for deployments: kubectl wait deployment.apps/slow condition met $ kubectl deploy/slow -- condition=available wait for Note that the condition for a deployment is , not . available ready We find to be a useful tool for change automation, properly ordering things of Kubernetes, and general Zen-like meditative states. We hope you will too! kubectl wait outside Previously published at https://starkandwayne.com/blog/silly-kubectl-trick-5-waiting-for-things-to-finish-up-2/