kubectl-node_shell

#!/bin/sh

context=""
kubeconfig=""
generator=""
node=""
namespace=""
while [ $# -gt 0 ]; do
  key="$1"

  case $key in
  --context)
    context="--context $2"
    shift
    shift
    ;;
  --kubeconfig)
    kubeconfig="--kubeconfig $2"
    shift
    shift
    ;;
  -n | --namespace)
    namespace="--namespace $2"
    shift
    shift
    ;;
  *)
    node="$1"
    shift
    ;;
  esac
done

if [ -z "$node" ]; then
  echo "Please specify node name"
  exit 1
fi

image="docker.io/library/alpine"
pod="nsenter-$(env LC_ALL=C tr -dc a-z0-9 < /dev/urandom | head -c 6)"

# Check the node
kubectl get node "$node" $context $kubeconfig >/dev/null || exit 1

overrides="$(
  cat <<EOT
{
  "spec": {
    "nodeName": "$node",
    "hostPID": true,
    "containers": [
      {
        "securityContext": {
          "privileged": true
        },
        "image": "$image",
        "name": "nsenter",
        "stdin": true,
        "stdinOnce": true,
        "tty": true,
        "command": [ "nsenter", "--target", "1", "--mount", "--uts", "--ipc", "--net", "--pid", "--", "bash", "-l" ]
      }
    ]
  }
}
EOT
)"

# Support Kubectl <1.18
m=$(kubectl version --client -o yaml | awk -F'[ :"]+' '$2 == "minor" {print $3+0}' )
if [ "$m" -lt 18 ]; then
  generator="--generator=run-pod/v1"
fi

echo "spawning \"$pod\" on \"$node\""
kubectl run --rm --image "$image" --overrides="$overrides" -ti "$pod" $generator $context $kubeconfig $namespace