Running Flatcar Linux on Google Compute Engine

Before proceeding, you will need a GCE account (GCE free trial ) and install gcloud on your machine. In each command below, be sure to insert your project name in place of <project-id>.

After installation, log into your account with gcloud auth login and enter your project ID when prompted.

Choosing a channel

Flatcar Linux is designed to be updated automatically with different schedules per channel. You can disable this feature, although we don't recommend it. Read the release notes for specific features and bug fixes.

Create 3 instances from the image above using our Ignition from example.ign:

The Stable channel should be used by production clusters. Versions of Flatcar Linux are battle-tested within the Beta and Alpha channels before being promoted. The current version is Flatcar Linux 2191.4.0.

gcloud compute instances create flatcar1 flatcar2 flatcar3 --image-project flatcar-cloud --image-family flatcar-stable --zone us-central1-a --machine-type n1-standard-1 --metadata-from-file user-data=config.ign

The Beta channel consists of promoted Alpha releases. The current version is Flatcar Linux 2219.2.0.

gcloud compute instances create flatcar1 flatcar2 flatcar3 --image-project flatcar-cloud --image-family flatcar-beta --zone us-central1-a --machine-type n1-standard-1 --metadata-from-file user-data=config.ign

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 Flatcar Linux 2234.0.0.

gcloud compute instances create flatcar1 flatcar2 flatcar3 --image-project flatcar-cloud --image-family flatcar-alpha --zone us-central1-a --machine-type n1-standard-1 --metadata-from-file user-data=config.ign

The Edge channel includes bleeding-edge features with the newest versions of the Linux kernel, systemd and other core packages. Can be highly unstable. The current version is Flatcar Linux 2219.99.1.

gcloud compute instances create flatcar1 flatcar2 flatcar3 --image-project flatcar-cloud --image-family flatcar-edge --zone us-central1-a --machine-type n1-standard-1 --metadata-from-file user-data=config.ign

Uploading an Image

Official Flatcar Linux images are not available on Google Cloud at the moment. However, you can run Flatcar Linux today by uploading an image to your account.

To do so, run the following command:

docker run -it quay.io/kinvolk/google-cloud-flatcar-image-upload \
  --bucket-name <bucket name> \
  --project-id <project id>

Where:

During execution, the script will ask you to log into your Google account and then create all necessary resources for uploading an image. It will then download the requested Flatcar Linux image and upload it to the Google Cloud.

To see all available options, run:

docker run -it quay.io/kinvolk/google-cloud-flatcar-image-upload --help

Usage: /usr/local/bin/upload_images.sh [OPTION...]

 Required arguments:
  -b, --bucket-name Name of GCP bucket for storing images.
  -p, --project-id  ID of the project for creating bucket.

 Optional arguments:
  -c, --channel     Flatcar Linux release channel. Defaults to 'stable'.
  -v, --version     Flatcar Linux version. Defaults to 'current'.
  -i, --image-name  Image name, which will be used later in Lokomotive configuration. Defaults to 'flatcar-<channel>'.

 Optional flags:
   -f, --force-reupload If used, image will be uploaded even if it already exist in the bucket.
   -F, --force-recreate If user, if compute image already exist, it will be removed and recreated.

The Dockerfile for the quay.io/kinvolk/google-cloud-flatcar-image-upload image is managed here.

Upgrade from Container Linux

You can also upgrade from an existing Container Linux system.

Container Linux Config

Flatcar Linux allows you to configure machine parameters, configure networking, launch systemd units on startup, and more via Container Linux Configs. These configs are then transpiled into Ignition configs and given to booting machines. Head over to the docs to learn about the supported features.

You can provide a raw Ignition config to Flatcar Linux via the Google Cloud console's metadata field user-data or via a flag using gcloud.

As an example, this config will configure and start etcd:

etcd:
  # All options get passed as command line flags to etcd.
  # Any information inside curly braces comes from the machine at boot time.

  # multi_region and multi_cloud deployments need to use {PUBLIC_IPV4}
  advertise_client_urls:       "http://{PRIVATE_IPV4}:2379"
  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_client_urls:          "http://0.0.0.0:2379"
  listen_peer_urls:            "http://{PRIVATE_IPV4}:2380"
  # generate a new token for each unique cluster from https://discovery.etcd.io/new?size=3
  # specify the initial size of your cluster with ?size=X
  discovery:                   "https://discovery.etcd.io/<token>"

Additional storage

Additional disks attached to instances can be mounted with a .mount unit. Each disk can be accessed via /dev/disk/by-id/google-<disk-name>. Here's the Container Linux Config to format and mount a disk called database-backup:

storage:
  filesystems:
    - mount:
        device: /dev/disk/by-id/scsi-0Google_PersistentDisk_database-backup
        format: ext4

systemd:
  units:
    - name: media-backup.mount
      enable: true
      contents: |
        [Mount]
        What=/dev/disk/by-id/scsi-0Google_PersistentDisk_database-backup
        Where=/media/backup
        Type=ext4

        [Install]
        RequiredBy=local-fs.target

For more information about mounting storage, Google's own documentation is the best source. You can also read about mounting storage on Flatcar Linux.

Adding more machines

To add more instances to the cluster, just launch more with the same Ignition config inside of the project.

SSH

You can log in your Flatcar Linux instances using:

gcloud compute ssh --zone us-central1-a core@<instance-name>

Users other than core, which are set up by the GCE account manager, may not be a member of required groups. If you have issues, try running commands such as journalctl with sudo.

Using Flatcar Linux

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