Check user of all containers in a Kubernetes cluster

k8s-check-container-user.sh

#!/bin/bash

kubectl get pods --all-namespaces -o 'custom-columns=:.metadata.namespace,:.metadata.name,:.spec.initContainers[*].name' |
while read line; do
  namespace=$(awk '{print $1}' <<<"$line")
  pod=$(awk '{print $2}' <<<"$line")
  containers=($(awk '{print $3}' <<<"$line" | tr , ' '))
  for container in "${containers[@]}"; do
    echo -n "$namespace | $pod | $container: "
    kubectl exec "$pod" -n "$namespace" -c "$container" -- whoami 2>/dev/null || echo "<unknown>"
  done
done