Difference between revisions of "Docker"

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(isolation)
m (Isolate containers with a user namespace)
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{{Cmd|vi /etc/init.d/docker}}
 
{{Cmd|vi /etc/init.d/docker}}
 
<pre>
 
<pre>
command_args="-p \"${pidfile}\" ${DOCKER_OPTS} --userns-remap=default"
+
DOCKER_OPTS="--userns-remap=default"                   
 +
 
 +
command_args="-p \"${pidfile}\" ${DOCKER_OPTS}"
 
</pre>
 
</pre>
  
''If i may recommend you, you should add also : '''--icc=false --no-new-security'''''
+
''If i may recommend you, you should add also : '''--icc=false --no-new-privileges'''''
  
 
== Example: How to install docker from Arch ==
 
== Example: How to install docker from Arch ==

Revision as of 09:10, 9 February 2018

Alpine makes a great docker container, because it is so small and optimized to be run in RAM. It might also might make a good controller for several docker containers with enough RAM. I haven't tested this yet Docker's setup is easy to use from command line. Commands can be run from an interactive shell, or through a configuration file called a "Dockerfile". docker.com has excellent walk-throughs on how to run, pull, setup a container, commit an image, and create a configuration file. hub.docker.com is a freemium setup, where the first private repository is free.

Installation

Run apk add docker to install Docker on Alpine Linux.

The Docker package is in the 'Community' repository, so if the apk add fails with unsatisfiable constraints, you need to edit the /etc/apk/repositories file to add (or uncomment) a line like:

http://dl-cdn.alpinelinux.org/alpine/edge/community

then run apk update to index the repository.


To start the Docker daemon at boot, run:

rc-update add docker boot


Then to start the Docker daemon manually, run:

service docker start


Note: On older version of Alpine Linux with older version of docker you'll also need to disable some kernel security flags in order to build images:

sysctl -w kernel.grsecurity.chroot_deny_chmod=0

sysctl -w kernel.grsecurity.chroot_deny_mknod=0

For more information, have a look at the corresponding Github issue.

Anyway, this weakening of security is not necessary to do with Alpine 3.4.x and Docker 1.12 as of August 2016 anymore.

Docker Compose

To install docker-compose, first install pip:

apk add py-pip


Then install docker-compose, run:

pip install docker-compose

Isolate containers with a user namespace

Note: Probably not the best way to do it but it work
adduser -DHs dockremap}}
echo dockremap:$(cat /etc/passwd\|grep dockremap\|cut -d: -f3):65536 >> /etc/subuid
echo dockremap:$(cat /etc/passwd\|grep dockremap\|cut -d: -f4):65536 >> /etc/subgid

vi /etc/init.d/docker

DOCKER_OPTS="--userns-remap=default"                    

command_args="-p \"${pidfile}\" ${DOCKER_OPTS}"

If i may recommend you, you should add also : --icc=false --no-new-privileges

Example: How to install docker from Arch

https://wiki.archlinux.org/index.php/Docker

How to use docker

The best documentation for how to use Docker and create containers is at the main docker site. Adding anything more to it here would be redundant.

http://docs.docker.com/

if you create an account at docker.com you can browse through other user's images and learn from the syntax in contributor's dockerfiles.

Official Docker image files are denoted by a blue ribon on the website.

See also