Last updated 2018-03-03

Install Docker Community Edition §

I am working on a clean CentOS 7 VM clone, so I don’t need to remove old versions, but I do need to set a new hostname.

• echo docker-centos7.stma | sudo tee /etc/hostname
• sudo hostname -F /etc/hostname

From the Docker Docs.

1. sudo curl -L https://download.docker.com/linux/centos/docker-ce.repo -o /etc/yum.repos.d/docker-ce.repo
2. sudo yum update
3. sudo yum install device-mapper-persistent-data docker-ce lvm2
4. sudo systemctl enable docker

Note that sudo systemctl is aliased to sctl in my bashrc.

Generate the initial directories §

1. sudo systemctl start docker
2. sudo systemctl stop docker

Configure the OverlayFS storage driver §

From the Docker Docs.

sudo vim /etc/docker/daemon.json

{
  "storage-driver": "overlay2",
  "storage-opts": ["overlay2.override_kernel_check=true"],
  ...
}

In Arch Linux §

The Arch Wiki has a different method of setting the options, using a Drop-in Snippet.

sudo systemctl edit docker

[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H fd:// -s overlay2

Set up user privileges §

Don’t do this for untrusted users. As detailed in the Docker Docs, it’s equivalent to giving a user full root access.

sudo usermod -aG docker stick

Set up remote access §

sudo vim /etc/docker/daemon.json

{
  ...
  "hosts": ["tcp://0.0.0.0:2375"],
  ...
}

The Docker Docs mention RHEL and CentOS overriding the hosts array, but I found that was not true in current CentOS 7. However, I did find that including "fd://" in the "hosts" array causes docker to fail on startup.

In Arch Linux §

The Arch Wiki has a different method of setting the options, using a Drop-in Snippet.

sudo systemctl edit docker

[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:2375 -H unix://var/run/docker.sock -s overlay2 

Try it out §

docker run hello-world

Optional: Take a snapshot §

1. history -c
2. Close -> ACPI Shutdown
3. Snapshots -> Take