kubectl-tmux-exec

A kubectl plugin that controls multiple pods simultaneously using Tmux.

It is to kubectl exec as csshX or pssh is to ssh.

Instead of exec bash into multiple pod's containers one-at-a-time, like kubectl exec pod{N} /bin/bash.

You can now use

kubectl tmux-exec -l app=nginx /bin/bash

Installation

Homebrew

Note: This is for Mac users only.

1. Install Homebrew.

2. brew install predatorray/brew/kubectl-tmux-exec

The script should be installed under /usr/local/bin/kubectl-tmux_exec by default. Please ensure the bin directory is in your $PATH environment variable.

Krew

Note: It is recommended for Linux users.

Although it works both on Mac and Linux, it is not recommended for Mac users, since you still may need to install the dependency gnu-getopt with the help of Homebrew.

1. Install Krew by following the user guide.

2. kubectl krew install tmux-exec

3. Install the dependencies. (Wiki: How-to-Install-Dependencies)

Manually

1. Download the latest release.

2. Unpack the kubectl-tmux-exec-*.tar.gz file and copy all the files to a directory, /usr/local/kubectl-tmux-exec for instance.

3. Add the bin/ directory to PATH. For example, add this line to your rc file: export PATH="$PATH:/usr/local/kubectl-tmux-exec/bin".

4. Install the dependencies. (Wiki: How-to-Install-Dependencies)

Usage

To execute this script as a plugin, a kubectl version prior to 1.12.0 is required and the latest version is preferred. Alternatively, you can also execute the script directly like kubectl-tmux_exec [...ARGS] if it is not supported.

By executing the command below, you can check if the script has been successfully added.

kubectl plugin list

The output should be like

The following compatible plugins are available:

/usr/local/bin/kubectl-tmux_exec

If it does not show in the list, check $PATH env again.

You can use the command below to get the usage of the script.

kubectl tmux-exec --help

# or
kubectl-tmux_exec --help

Options

Flag	Usage
-V --version	Print the version information
-l --selector	Selector (label query) to filter on, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2) You must either use --selector or --file option.
-f --file	Read pod names line-by-line from a file. You must either use --selector or --file option.
-c --container	Container name. If omitted, the first container in the pod will be chosen
-i --stdin	Pass stdin to the container (deprecated, since it's enabled by default)
-t --tty	Stdin is a TTY (deprecated, since it's enabled by default)
-d --detach	Make the Tmux session detached
-n --namespace=	The namespace scope for this CLI request (can be applied multiple times)
--context	The name of the kubeconfig context to use (can be applied multiple times)
-A --all-namespaces	If present, list and execute the requested object(s) across all namespaces. Namespace in current context is ignored even if specified with --namespace.
-C --enable-control-mode	Start tmux in control mode and echo is disabled. (See: iTerm2 Integration)
--remain-on-exit	Remain Tmux window on exit
--select-layout	One of the five Tmux preset layouts: even-horizontal, even-vertical, main-horizontal, main-vertical, or tiled.
--session-mode	Where tmux is opened: auto, new-session, current-session

The usage of these options is also available by --help.

Example

The tmux-exec is similar to exec, except that it requires label selectors while exec requires a pod name.

To bash into all pod containers that share some common labels, foo=bar for instance.

kubectl tmux-exec -l foo=bar /bin/bash

After you have successfully bash-ed into your selected containers, a Tmux window is opened actually, where each pane displays the execution result of each pod's container. Your keyboard inputs will be synchronized to all those panes.

If you are not familar with Tmux, you can have a look at tmux's man page or online tutorials. Or you can see the cheatsheet below, which will be sufficient I think.

iTerm2 Integration

Since iTerm2 has been integrated with tmux, we can have a better native user interface, instead of remembering all the shortcuts.

All we have to do is to turn on the Control Mode, by adding the option -C / --enable-control-mode when executing the script. After that, the iTerm2 application will take full control of the tmux session.

For example, executing the commands below in an iTerm2 session

kubectl tmux-exec -C -l app=nginx /bin/bash

will result in something like the screenshot below.

Note that, the synchronize-panes will be disabled automatically in this mode, since the iTerm2 provides a much easier way to achieve this. To turn this on, press ⌘ + ⌥ + i, or click "Shell" - "Broadcast Input" - "Broadcast Input to All Panes in Current Tab" in the menu bar.

Shell Auto-completion

Please check this wiki for more information.

Tmux Cheatsheet

All Tmux command starts with a PREFIX. By default the PREFIX is Ctrl + b. I will use C-b below to stand for it.

C-b d, detach from the session. After that, the Tmux will be running in the backgroud. You can type tmux a to re-attach.

C-b :setw synchronize-panes off, turn off synchronizing inputs to all panes.

C-b :setw synchronize-panes on, turn on synchronizing inputs to all panes.

C-b <ARROW-KEY>, move cursor between panes.

C-b xy, close the current pane.

C-b &y, close the window including all panes.

Discussion & Support

Please feel free to open an issue if you find any bug or have any suggestion.

Alternatively, join the Google Group and start a conversation.

Other plugins

kubectl-alias: the missing alias command for kubectl.