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:

Vagrant.configure("2") do |config|
  config.vm.box = "phusion/ubuntu-14.04-amd64"
  config.vm.provision "docker"
  config.vm.network :forwarded_port, host: 8080, guest: 8080
  config.vm.provider :virtualbox do |vb|
    vb.name = "docker-proxy"
  end
end

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

Vagrant.configure("2") do |config|
  config.vm.provider "docker" do |d|
    d.image   = "dockerfile/nginx"
    d.ports   = ["8080:80"]
    d.vagrant_vagrantfile = "./Vagrantfile.proxy"
  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]

In a single machine environment you can omit the container name and just run vagrant docker-shell.

docker-shell is a shortcut for docker-exec 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

In a multimachine environment docker-exec (and docker-shell) must be followed by at least 1 container name defined by config.vm.define. For example, for this Vagrantfile

Vagrant.configure("2") do |config|
  config.vm.define "web" do |v|
    v.vm.provider "docker" do |d|
      d.image   = "dockerfile/nginx"
      d.ports   = ["8082:80"]
      d.name    = "nginx"
      d.vagrant_vagrantfile = "./Vagrantfile.proxy"
    end
  end
end

The container name passed to docker-exec is web even though a docker assigned the container the name "nginx".

Examples

Everything after the double hyphen is sent to docker's exec command. For example, to create a new file in a container named nginx:

vagrant docker-exec web -- 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 nginx2 -- ifconfig | grep inet
==> nginx:           inet addr:172.17.0.5  Bcast:0.0.0.0  Mask:255.255.0.0
==> nginx:           inet6 addr: fe80::42:acff:fe11:5/64 Scope:Link
==> nginx:           inet addr:127.0.0.1  Mask:255.0.0.0
==> nginx:           inet6 addr: ::1/128 Scope:Host
==> nginx2:           inet addr:172.17.0.4  Bcast:0.0.0.0  Mask:255.255.0.0
==> nginx2:           inet6 addr: fe80::42:acff:fe11:4/64 Scope:Link
==> nginx2:           inet addr:127.0.0.1  Mask:255.0.0.0
==> nginx2:           inet6 addr: ::1/128 Scope:Host

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

You can also specify containers as you would any other vagrant command:

vagrant docker-exec /nginx\d?/ -- ps aux | grep www-data

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

Author

William Kolean william.kolean@gmail.com