Shell provisioning using docker-exec instead of SSH

[dbichko]

As @chrisroberts suggested, I am resubmitting the feature request from #4179, since it wasn't actually addressed by #7377.

Being able to provision containers in the docker provider without an SSH daemon would greatly simplify (and speed up!) configuration, especially for multi-machine setups.

I currently have multiple Dockerfiles that just add sshd to public images from Docker Hub (postgresql, tomcat, nginx, etc); provisioning with exec would allow me to eliminate all the docker build steps, and just use the public images directly.

Ideally, the shell provisioner would prefer exec when using the docker provider (or at least fall back to it when ssh isn't available), but a separate provisioner with "shell-like" functionality would work to.

It seems that #7377 already did the heavy lifting in enabling docker exec support, and allowing the shell provisioner to use it would be quite doable?

Thank you.

[GrzegorzDrozd]

Hi.
Please do that! I need to use bunch of shell scripts around Vagrant file to use docker-run BUT it would be so much easier to just inline that in Vagrantfile!

Thank you and have a nice day.

[mtekel]

Now that vagrant supports running docker directly on MacOS and Win, this would be even more useful. Ability to use any docker image without modification is a strong feature. We would be now able to use all kind of official images, that are not made for Vagrant. And with docker images, it is quite unusual to have sshd built in (...no need for that, when you can docker exec).

[lucasyvas]

Packer supports this I think. Using SSH is not a good choice as it isn't set up in most Docker images.

[techtonik]

This should be renamed to docker exec as it is standard command now and not some script.

[techtonik]

Warning "Provisioners will not be run since container doesn't support SSH." is output from two places.

1. action_provision handler:
   

   vagrant/plugins/providers/docker/action.rb

   Line 74 in 1f565b8

   I18n.t("docker_provider.messages.provision_no_ssh"),

2. action_start handler:
   

   vagrant/plugins/providers/docker/action.rb

   Line 223 in 1f565b8

   I18n.t("docker_provider.messages.provision_no_ssh"),

[techtonik]

Provisioner, such as shell checks how to execute commands remotely here:

vagrant/plugins/provisioners/shell/provisioner.rb

Lines 25 to 32 in 1f565b8

	case @machine.config.vm.communicator
	when :winrm
	provision_winrm(args)
	when :winssh
	provision_winssh(args)
	else
	provision_ssh(args)
	end

Work with SSH is provided be communicator so before Docker provider can use that, there should be a communicator plugin written with docker exec as ssh replacement. Then it should be set somewhere to appear in machine.config.vm.communicator.

[ProxiBlue]

Hello:

there should be a communicator plugin written with docker exec as ssh replacement

this now exists:

https://github.com/ProxiBlue/vagrant-communicator-docker

any SSH related commands will be handled using docker API