Butcher

Butcher is a shmux-based shell for executing commands within Chef-managed infrastructure.

Installation

First, you need to install shmux itself. You may check whether there's a package available for your distribution, or just build it from sources (latest available release).

Butcher itself can be installed via setup.py, like this

sudo python setup.py install

Configuration

Copy butcherrc_example to ~/.butcherrc and apply your changes

Usage

First run of butcher may take some time as it fetches hosts information from Chef servers you configured in ~/.butcherrc. After that, you can start it with -a parameter, i.e butcher -a to use cached data (this data is periodically refreshed in background while butcher is running).

Once you get into butcher shell, your current environment, region and user will be displayed in prompt string. Environments are chef servers you configured, you are always working within specific environment i.e with single Chef server. Regions are actual Chef environments, you can select specific one with region command or say unset region to use all. User is actualy user that will be used for ssh-ing to hosts, can be changed with command set user or reseted to current user using unset.

Main commands are:

• hostlist SELECTOR - displays hosts matching SELECTOR
• p_exec SELECTOR CMD - executes CMD on hosts matching SELECTOR in parallel (maximum number of threads can be set using threads commands)
• exec SELECTOR CMD - same as p_exec, but sequentially, in one thread.

SELECTOR is comma-separated list of hosts or expressions like %ROLE[@REGION], where ROLE is actual chef role (* glob can be used) and REGION is region, i.e. Chef environment (if missing, current region will be used)