Shell script should wait until kubernetes pod is running

Question

In a simple bash script I want to run multiple kubectl and helm commands, like:

helm install \
  cert-manager jetstack/cert-manager \
  --namespace cert-manager \
  --create-namespace \
  --version v1.5.4 \
  --set installCRDs=true
kubectl apply -f deploy/cert-manager/cluster-issuers.yaml

My problem here is, that after the helm install command I have to wait until the cert-manager pod is running, then the kubectl apply command can be used. Right now the script is calling it too early, so it will fail.

Answer 1

As stated in the comments kubectl wait is the way to go.
Example from the kubectl wait --help

Examples:
  # Wait for the pod "busybox1" to contain the status condition of type "Ready"
  kubectl wait --for=condition=Ready pod/busybox1

This way your script will pause until specified pod is Running, and kubectl will output

<pod-name> condition met

to STDOUT.

---

kubectl wait is still in experimental phase. If you want to avoid experimental features, you can achieve similar result with bash while loop. By pod name:

while [[ $(kubectl get pods <pod-name> -o 'jsonpath={..status.conditions[?(@.type=="Ready")].status}') != "True" ]]; do
   sleep 1
done

or by label:

while [[ $(kubectl get pods -l <label>=<label-value> -o 'jsonpath={..status.conditions[?(@.type=="Ready")].status}') != "True" ]]; do
   sleep 1
done