Docker

	Note
	This page is actively maintained by the Grid'5000 team. If you encounter problems, please report them (see the Support page). Additionally, as it is a wiki page, you are free to make minor corrections yourself if needed. If you would like to suggest a more fundamental change, please contact the Grid'5000 team.

Docker is a software technology that provides operating-system-level virtualization. In this page, we present some tools that are specifically designed to use Docker on Grid'5000.

Installing Docker from a node in the standard environment

You can install and use Docker from a node with the standard environment by following these instructions:

Reserve a node

fnancy:

oarsub -I

See Getting_Started for more reservation options.

Install Docker from the standard environment

The script g5k-setup-docker, available from the standard environment, installs Docker locally and makes Docker commands available without user needing to log out (by giving read write permissions to the file /var/run/docker.sock)

node:

g5k-setup-docker -t

The -t option allows to use /tmp/ to store docker images, which is useful because /tmp/ has more disk space available. Technically speaking, it does a bind mount of /tmp/docker on /var/lib/docker.

Run Docker

You can now check that Docker is up and running

node:

docker run hello-world

Installing Docker from a deployed node

In addition to the standard environment, g5k-setup-docker works with the environments debian11-nfs and debian11-big (as well as with debian10-nfs and debian10-big).

Reserve a node, deploy an environment, connect to the node and run the script as root with its full path:

root@node:

/grid5000/code/bin/g5k-setup-docker

You can also use the -t option to store docker images in /tmp/ to have more space, but be aware that everything will be deleted if you reboot the node.

Installing nvidia-docker

On nodes with one or more GPUs, you may want to use Nvidia's Docker container images (e.g. see [1]). To do so, you have to install Nvidia's nvidia-docker.

To ease this task, Grid'5000 provides a script to automate the installation. Just run :

node:

g5k-setup-nvidia-docker -t

Options are the same as with the g5k-setup-docker script presented above. Please note that you can use g5k-setup-docker or g5k-setup-nvidia-docker, but not both all together.

Using docker-cache.grid5000.fr

Due do the rate limiting of docker hub you might experience some troubles to fetch images. As a result you can use docker-cache.grid5000.fr which is a registry mirror.

To enable the use of the cache from a Grid'5000 node (as root or using sudo-g5k), edit /etc/docker/daemon.json with:

{
  "registry-mirrors": [
    "http://docker-cache.grid5000.fr"
  ]
}

then restart docker:

systemctl restart docker

The cache is automatically configured by g5k-setup-docker.

Logging in to dockerhub to bypass rate limiting

Even with the Grid'5000 docker cache, you can still be rate-limited by the dockerhub.

To bypass the rate-limiting, you can associate the local docker daemon with your dockerhub account:

• Generate a read-only token on dockerhub: https://hub.docker.com/settings/security?generateToken=true and select the "Public Repo Read-Only" permission
• Use the token to login on your Grid'5000 machine:

 docker login -u yourlogin -p yourtoken

The credentials will be saved in ~/.docker/config.json. If you use your regular Grid'5000 account, then it will be saved in your shared NFS home, and it should be used by all your nodes. If you use the root account to SSH on your nodes, then you need to repeat this configuration on each node.

Avoid network conflict

The default network used by docker is 172.16.0.1/16 which is use internally on Grid'5000 thus this can be a source of conflict.

If you want to avoid any conflict you can set an other network. On debian you will have to edit /etc/default/docker and specify the network you want to use like this:

DOCKER_OPTS="--bip=192.168.42.1/24"

Using docker-machine and docker-g5k

The Spirals Team in Lille developed two tools to ease Docker usage on Grid'5000:

• a docker-machine driver
• the docker-g5k program

Provision a node with docker-machine

The driver for docker-machine allows you to reserve a node on Grid'5000 and to install a Linux image and Docker Engine on it, from your computer and in one single command. The reserved node is then available from commands like docker-machine ssh (standard ssh commands don't work when nodes are reserved with docker-machine).

Create a Swarm with docker-g5k

The docker-g5k program allows you to reserve several nodes, possibly on different sites, and to install a Linux image and Docker Engine on each node, in one single command. This command configures a Swarm, i.e. a set of Docker containers distributed over several nodes that communicate with each other.

Managing Docker images

One difficult aspect of using Docker is efficient images management, as (1) it is often required to load such images on many nodes simultaneously; (2) Grid'5000 connection to the internet is limited to 10 Gbps. The following strategies are recommended to manage Docker images:

Use docker load/save

To load and save images quickly, we encourage you to use docker load and docker save commands, with .tar docker images stored in your Grid'5000 home. Users home are NFS mounted, with good network performance.

Example

node1:

docker pull alpine docker save -o ~/alpine.tar alpine

node2:

docker load -i ~/alpine.tar docker run -it alpine

You can also use docker load command instead of retrieving the image from Docker Hub, when deploying a Swarm with docker-g5k.

Example with docker-g5k

Give read rights to your image

frontend:

chmod 644 ~/alpine.tar

Deploy three Docker nodes in Nancy (activate the Grid'5000 VPN before launching this command)

laptop:

docker-g5k create-cluster --g5k-username "user" --g5k-password "********" --g5k-image "jessie-x64-std" --g5k-reserve-nodes "nancy:3"

Load Alpine image on each node

laptop:

for i in {0..2}; do docker-machine ssh nancy-${i} "docker load -i /home/user/alpine.tar"; done

Use a persistent virtual machine to host your registry

If you want to benefit from a private registry with good network performance, and are ready to manually install your own registry, you can request a Persistent Virtual Machine. You can look at Harbor or Portus open source projects, in order to install your own registry.