coreos-cloudinit allows a user to customize CoreOS machines by providing either an executable script or a cloud-config document as instance user-data. See below to learn how to use these features.
Only a subset of cloud-config functionality is implemented. A set of custom parameters were added to the cloud-config format that are specific to CoreOS.
Provided public SSH keys will be authorized for the core user.
The keys will be named "coreos-cloudinit" by default.
Override this with the --ssh-key-name flag when calling coreos-cloudinit.
The value of coreos.etcd.discovery_url will be used to discover the instance's etcd peers using the etcd discovery protocol. Usage of the public discovery service is encouraged.
The coreos.update namespace has two keys:
coreos.update.serveris the auto update URL.coreos.update.groupis the group your machine will join.
These fields will be written out to and replace /etc/coreos/update.conf. If only one of the parameters is given it will only overwrite the given field.
Simply set your user-data to a script where the first line is a shebang:
#!/bin/bash
echo 'Hello, world!'
#cloud-config
coreos:
etcd:
discovery_url: https://discovery.etcd.io/827c73219eeb2fa5530027c37bf18877
fleet:
autostart: yes
ssh_authorized_keys:
- ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC0g+ZTxC7weoIJLUafOgrm+h...