CODEWITHSUNDEEP
node.jsdocker
scripty
scripty

Reputation: 81

Starting and stopping docker container from other container

I need to start, stop and restart containers from inside another container.

For Example:

Container A -> start Container B

Container A -> stop Container C

My Dockerfile:

FROM node:7.2.0-slim

WORKDIR /docker
COPY . /docker
CMD [ "npm", "start" ]

Docker Version 1.12.3

I want to avoid using a ssh connection. Any Ideas?

Upvotes: 7

Views: 4331

Answers (1)

Andreas Jägle
Andreas Jägle

Reputation: 12270

Per se a container runs in an isolated environment (e.g. with its own file system or network stack) and thus has no direct way to interact with the host it is running on. This is of course intended that way to allow for real isolation.

But there is a way to run containers with some more privileges. To talk to the docker daemon on the host, you can for example mount the docker socket of the host system into the container. This works the same way as you probably would mount some host folder into the container.

docker run -v /var/run/docker.sock:/var/run/docker.sock yourimage

For an example, please see the docker-compose file of the traefik proxy which is a process that listenes for starting and stopping containers on the host to activate some proxy routes to them. You can find the example in the traefik proxy repository.

To be able to talk to the docker daemon on the host, you then also need to have a docker client installed in the container or use some docker api for your programming language. There is an official list of such libraries for different programming languages in the docker docs.

Of course you should be aware of what privileges you give to the container. Someone who manages to exploit your application could possibly shut down your other containers or - even worse - start own containers on your system which can easily be used to gain control over your system. Keep that in mind when you build your application.

Upvotes: 10

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