[Container-tools] Version incompatibility of Docker client and server - projectatomic/vagrant-adbinfo issue #85

[Shubham Minglani]

Hi community,

I am writing this referring to Issue #85 on projectatomic/vagrant-adbinfo raised by Bama yesterday.

You can read/discuss about it here: https://github.com/projectatomic/vagrant-adbinfo/issues/85

Summary:

While using vagrant-adbinfo plugin with Docker client of local machine to connect to Docker in the Vagrant box, a version mismatch error pops up due to difference in the API versions and the API not being backward compatible.

To make both of them talk, we need to get the versions to match. For the same, the following options are being considered:

- If there is a version mismatch, create another vagrant vm with docker client of appropriate version installed and route docker traffic from there.
- Package the docker client of appropriate version with a slightly modified name 'adb-docker' (this could be done through links as well. ie newname link pointing to packaged docker client in respective users bin directory) for example.
- Check for version mismatch, and with users permission, upgrade or downgrade accordingly.

Besides these, another approach was proposed today -

Instead of using Docker CLI client on the base machine, can Remote API [1] or one of these Remote API clients [2] be used to access Docker in the Vagrant VM? This way upgrading or downgrading Docker on the base machine does not have to be worried about, and this will also work across platforms.

However, in the case of using:

Remote API [1]:
- Multiple API versions have to be supported.
- Effectively, this is like maintaining a new Docker Remote API client.

Remote API client [2]:
- If these are well maintained (Docker does not maintain these, except docker-py [3]), then each API version does not have to be supported and code remains the same.
- These might not have support for all the Docker CLI client features (even docker-py does not support 'everything' which the CLI client does).

On another note, how about a hybrid approach? When the Remote API client does not work (feature not supported or version incompatibility), the Remote API can be used to do that thing.

It would be great if community gives some feedback on this issue, so I'm posting it here.

Please correct me if I'm wrong or talking off-track!

Regards,
Shubham Minglani

P.S. It's my first email here, so open to rectifications :)

[1] https://docs.docker.com/engine/reference/api/docker_remote_api/
[2] https://docs.docker.com/engine/reference/api/remote_api_client_libraries/
[3] https://github.com/docker/docker-py