CoreOS Setup Tutorial

A container-based cluster installation, using CoreOS.

Create configuration

You need to create a configuration file containing the informations used to install CoreOS.

This is an example based on mine: cloud-config.yaml. Note that you should customize it according to your host / cluster parameters.

Installation

$ _device="/dev/sda" # Set to your device path.
$ _channel="stable" # Set to "stable" or "beta". I usually prefer stable since it's what used normally in production.
$ _config="/home/core/cloud-config.yaml" # The path to the configuration file (see above).
$ sudo coreos-install -d "${_device}" -C "${_channel}" -c "${_config}"

Troubleshooting

GPT:Alternate GPT header not at the end of the disk

After installation if you get the message: GPT:Alternate GPT header not at the end of the disk. you should fix that issue by running parted:

$ _device="/dev/sda" # Set to your device path.
$ sudo parted "${_device}"

Then execute the command: print. You will be prompted with Fix/Ignore/Cancel questions and respond Fix to all of those questions. After that, execute the command quit to exit from parted.

Now your system is ready for the first boot. Execute:

$ sudo systemctl reboot

to reboot your system.

Login

To login you should use SSH with the user that owns the private-key matching the deployed public-key as the core user:

$ _host_ip="10.0.10.1" # Set to your CoreOS host IP address (the same as configured in `cloud-config.yaml`).
$ ssh core@${_host_ip}

Boom! You'd be in!