vagrant-docker-exec

This plugin allows you to run docker exec commands from your host. When running docker in a proxy, this will save you the effort of sshing into the proxy to run docker exec. If you have multiple running containers, you can exec a command that runs on each container sequentially. Visit Docker's command reference for details on the exec command.

Known Issues

Docker exec requires Docker 1.3.0 or higher. On non-Linux system, the docker in boot2docker provided by Vagrant is version 1.2 and does not support the exec command, so a custom docker host is required.

You can find more information on setting up a custom docker host on the Vagrant blog but basically, create Vagrantfile.proxy:

# -*- mode: ruby -*-
# vi: set ft=ruby :
Vagrant.configure(2) do |config|
  config.vm.box = "phusion/ubuntu-14.04-amd64"
  config.vm.provision "docker"
  config.vm.network :forwarded_port, host: 80, guest: 80
  config.vm.provider :virtualbox do |vb|
    vb.name = "docker-exec-proxy"
  end
end

And then use the vagrant_vagrantfile setting to reference your custom host in your Vagrantfile:

# -*- mode: ruby -*-
# vi: set ft=ruby :
Vagrant.configure(2) do |config|
  config.vm.define "nginx" do |v|
    v.vm.provider "docker" do |d|
      d.image   = "dockerfile/nginx"
      d.ports   = ["80:80"]
      d.name    = "nginx"
      d.vagrant_vagrantfile = "./Vagrantfile.proxy"
    end
  end
end

This plugin has been tested on Mac OS X and VirtualBox.

Getting Started

To install the plugin, run the following command:

vagrant plugin install vagrant-docker-exec

Usage

A common use case for the exec command is to open a new shell in a running conatiner. To make it easy, run the docker-shell shortcut:

vagrant docker-shell [container]

If you're running a docker host, then you are running in a multi-host environment and the container name is required, even if only one docker container is running.

docker-shell is a shortcut for running Bash in an interactive shell:

vagrant docker-exec -t nginx -- bash

The syntax for docker-exec is:

vagrant docker-exec [options] [container] -- [command] [args]

Options are:
--[no-]detach Run in the background
-t, --[no-]tty Open an interactive shell

Everything after the double hyphen is sent to docker's exec command.

As an example, to create a new file in a container named nginx:

vagrant docker-exec nginx -- touch /var/www/html/test.html

If the command produces output, the output will be prefixed with the name of the container.

vagrant docker-exec nginx -- ifconfig
==> nginx: eth0      Link encap:Ethernet  HWaddr 02:42:ac:11:00:02  
==> nginx:           inet addr:172.17.0.2  Bcast:0.0.0.0  Mask:255.255.0.0
==> nginx:           inet6 addr: fe80::42:acff:fe11:2/64 Scope:Link
==> nginx:           UP BROADCAST RUNNING  MTU:1500  Metric:1
==> nginx:           RX packets:24 errors:0 dropped:0 overruns:0 frame:0
==> nginx:           TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
==> nginx:           collisions:0 txqueuelen:0 
==> nginx:           RX bytes:1944 (1.9 KB)  TX bytes:648 (648.0 B)
==> nginx: 
==> nginx: lo        Link encap:Local Loopback  
==> nginx:           inet addr:127.0.0.1  Mask:255.0.0.0
==> nginx:           inet6 addr: ::1/128 Scope:Host
==> nginx:           UP LOOPBACK RUNNING  MTU:65536  Metric:1
==> nginx:           RX packets:0 errors:0 dropped:0 overruns:0 frame:0
==> nginx:           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
==> nginx:           collisions:0 txqueuelen:0 
==> nginx:           RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

The name of the container is only required for interactive shells. To run a command on multiple running containers, omit the container name:

vagrant docker-exec -- hostname
==> nginx: 231e57e57825
==> nginx2: 6ebced94866b

Note that all exec commands run by docker are run as the root user.

Author

William Kolean william.kolean@gmail.com