Docker: Difference between revisions
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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. | 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 == | ||
<code>apk add docker</code> | Run <code>apk add docker</code> 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: | 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: | ||
<code>http://dl- | <code>http://dl-cdn.alpinelinux.org/alpine/edge/community</code> | ||
then run <code>apk update</code> to index the repository. | |||
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<code>rc-update add docker boot</code> | <code>rc-update add docker boot</code> | ||
'''Then to start the Docker daemon manually, run:''' | '''Then to start the Docker daemon manually, run:''' | ||
<code>service docker start</code> | <code>service docker start</code> | ||
{{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:}} | |||
<code>sysctl -w kernel.grsecurity.chroot_deny_chmod=0</code> | |||
<code>sysctl -w kernel.grsecurity.chroot_deny_mknod=0</code> | |||
For more information, have a look at the [https://github.com/docker/docker/issues/20303 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 === | === Docker Compose === | ||
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<code>pip install docker-compose</code> | <code>pip install docker-compose</code> | ||
== Isolate containers with a user namespace == | |||
{{Note|Probably not the best way to do it but it work}} | |||
<pre> | |||
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 | |||
</pre> | |||
and add in '''/etc/init.d/docker''' | |||
before : '''command="${DOCKERD_BINARY:-/usr/bin/dockerd}"''' | |||
<pre> | |||
DOCKER_OPTS="--userns-remap=default" | |||
</pre> | |||
''You may also consider these options : '''--icc=false --no-new-privileges''''' | |||
== Example: How to install docker from Arch == | == Example: How to install docker from Arch == | ||
https://wiki.archlinux.org/index.php/Docker | https://wiki.archlinux.org/index.php/Docker | ||
== '''How to use docker''' == | == '''How to use docker''' == | ||
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Official Docker image files are denoted by a blue ribon on the website. | Official Docker image files are denoted by a blue ribon on the website. | ||
== See also == | |||
* [https://www.erianna.com/creating-a-alpine-linux-repository/ Creating & Hosting an Alpine Linux Package Repository for Docker Packages] | |||
[[Category:Virtualization]] |
Revision as of 09:13, 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
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
adduser -DHs dockremap}} echo dockremap:$(cat /etc/passwd\|grep dockremap\|cut -d: -f3):65536 >> /etc/subuid echo dockremap:$(cat /etc/passwd\|grep dockremap\|cut -d: -f4):65536 >> /etc/subgid
and add in /etc/init.d/docker
before : command="${DOCKERD_BINARY:-/usr/bin/dockerd}"
DOCKER_OPTS="--userns-remap=default"
You may also consider these options : --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.
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.