Run kubectl exec in multiple pods in a single tmux session

tmux-exec.sh

#!/bin/bash
#
# Example:
#    $ bash tmux-exec.sh <app>
#    $ bash tmux-exec.sh <app> <namespace>

if [ -n "$1" ]; then
  NAME="$1"
else
  echo "Pleae specify app.kubernetes.io/name"
  exit 1
fi

if [ -n "$2" ]; then
  NAMESPACE="$2"
else
  NAMESPACE="$(kubectl config view --minify -o jsonpath='{..namespace}')"
fi

tmux_args='new-session -n '"${NAMESPACE}/${NAME}"' ;'
for podname in `kubectl get pods -l app.kubernetes.io/name="${NAME}" -n "${NAMESPACE}" --no-headers -o custom-columns=":metadata.name"`; do
    tmux_args="${tmux_args} split-window -v kubectl exec -it ${podname} -n "${NAMESPACE}" -- bash; select-layout even-horizontal ; "
done

tmux ${tmux_args} \
  kill-pane -t 1 \; \
  select-layout even-horizontal \; \
  select-layout even-vertical \; \
  set-option -w synchronize-panes \; \
  attach