Upgrading CoreOS With Deis Onboard

Deis have disable the auto update facility in CoreOS by default due to specific technical reason.

To update to the latest release of CoreOS we must trigger the update manually using following command.

sudo systemctl unmask update-engine.service
sudo systemctl start update-engine.service
sudo update_engine_client -update

For those who is not familiar with CoreOS, you will notice the argument unmask of systemctl first command line. This service have been marked as masked to make it impossible to start nor enabled by the system itself. It is part of CoreOS systemd feature where it introduce granular level of service management.

A completed CoreOS update required a reboot as it will change the passive update partition to become active upon boot process. The update-engine service need to be stop and mask back to prevent the automatic update process in the future.

sudo systemctl stop update-engine.service
sudo systemctl mask update-engine.service

We can verify successful update with following command.

cat /etc/lsb-release