CoreOS Container Linux Logo

A container-focused OS that's designed for painless management in large clusters

Running CoreOS Container Linux on is a regional IaaS designed to help meet regulatory or security requirements by storing data in Canada. Container Linux is a supported operating system for VMs on the infrastructure.

Choosing a channel

Container Linux is designed to be updated automatically, with three channels of different update schedules: Stable, Beta, and Alpha. You can disable this feature, although we don't recommend it. Read the release notes for specific features and bug fixes.

The Container Linux image is built from the official stable release CloudStack image.

The Alpha channel closely tracks master and is released frequently. The newest versions of system libraries and utilities will be available for testing. The current version is Container Linux 2514.1.0. To use the Alpha channel on, select the "CoreOS Stable" template and update the cloud-config to [change the channel to alpha][switching-channels]:

    group: alpha
CoreOS cloud-configs can validated using the online validator.

The Beta channel consists of promoted Alpha releases. The current version is Container Linux 2513.2.0. To use the Beta channel on, use the "CoreOS Stable" template and update the cloud-config to [change the channel to beta][switching-channels]:

    group: beta
CoreOS cloud-configs can validated using the online validator.

The Stable channel should be used by production clusters. Versions of Container Linux are battle-tested within the Beta and Alpha channels before being promoted. The current version is Container Linux 2512.3.0.

Region Template Name Template ID
Compute - East CoreOS Stable f3d810d8-4e08-4ffb-afe3-6a71e3ce9062


Container Linux allows you to configure machine parameters, launch systemd units on startup, and more via cloud-config. Jump over to the docs to learn about the supported features. Cloud-config is intended to bring up a cluster of machines into a minimal useful state and ideally shouldn't be used to configure anything that isn't standard across many hosts. Once the machine is created, cloud-config cannot be modified.

You can provide cloud-config data using management portal or through the CloudStack API. When using CloudStack API, the cloud-conf must be base64 encoded as the userdata parameter.

The current cloud-config example uses a data disk as the docker datastore (/var/lib/docker).

    # generate a new token for each unique cluster from
    # specify the initial size of your cluster with ?size=X
    # multi-region and multi-cloud deployments need to use $public_ipv4
    advertise-client-urls: http://$private_ipv4:2379,http://$private_ipv4:4001
    initial-advertise-peer-urls: http://$private_ipv4:2380
    # listen on both the official ports and the legacy ports
    # legacy ports can be omitted if your application doesn't depend on them
    listen-peer-urls: http://$private_ipv4:2380
    - name: etcd2.service
      command: start
    - name: fleet.service
      command: start
    - name: format-ephemeral.service
      command: start
      content: |
        Description=Formats the ephemeral drive
        ExecStart=/usr/sbin/wipefs -f /dev/xvdb
        ExecStart=/usr/sbin/mkfs.btrfs -f /dev/xvdb
    - name: var-lib-docker.mount
      command: start
      content: |
        Description=Mount ephemeral to /var/lib/docker
CoreOS cloud-configs can validated using the online validator.

The $public_ipv4 substitution variable is not supported in cloud-config on To use a multi-region cluster, the cluster configuration and the port-forwarding must be done manually.

Adding more machines

To add more instances to the cluster, just launch more with the same cloud-config in the same VPC. New instances will join the etcd2 cluster automatically.

Launching instances

Before deploying Container Linux on, you need the following:

  • An account on
  • Access to an Environment with a running VPC. VPC and subnet creation are not part of the current documentation, refer to online help.
  • Your public SSH-key added into your environment.

Using admin portal

  1. Once logged into your organization; go into Services, select your environment, then click "Add instance":
Environment instances inventory
  1. Define the instance name, offering type and select the template "CoreOS Stable":
New instance details
  1. Create a data volume. This volume will be mounted in /var/lib/docker, as defined in the cloud-config excerpt. This step is optional:
New instance data volumes
  1. Enable port forwarding rule for SSH (Optional) and assign your SSH key to the new instance:
New instance connectivity
  1. Copy your cloud-config content into the User data section (optional):
New instance user data
  1. Once the instance is created and running, you can SSH into the instance as username core, using instance private IP if remote access to your VPC is configured such as remote management VPN. If you enbled port forwarding for SSH on step #4, you can find the assigned public IP in the instance details section:
Instance details
$ ssh -i ~/.ssh/user1_rsa core@74.X.X.X
CoreOS stable (766.4.0)
core@coreos-node01 ~ $ df -h
Filesystem      Size  Used Avail Use% Mounted on
devtmpfs        483M     0  483M   0% /dev
tmpfs           496M     0  496M   0% /dev/shm
tmpfs           496M  292K  496M   1% /run
tmpfs           496M     0  496M   0% /sys/fs/cgroup
/dev/xvda9      2.0G   19M  1.9G   1% /
/dev/xvda3      985M  390M  545M  42% /usr
/dev/xvda1      128M   32M   97M  25% /boot
tmpfs           496M     0  496M   0% /tmp
tmpfs           496M     0  496M   0% /media
/dev/xvda6      108M   80K   99M   1% /usr/share/oem
/dev/xvdb        40G   17M   38G   1% /var/lib/docker
core@coreos-node01 ~ $ etcdctl member list
7cb50ab9db389524: name=6a02cad1a70840d8a6ac2c5d3bf80aea peerURLs= clientURLs=,

Using CoreOS Container Linux

Now that you have a machine booted it is time to play around. Check out the Container Linux Quickstart guide or dig into more specific topics.