83 lines
2.4 KiB
Markdown
83 lines
2.4 KiB
Markdown
|
# Customize CoreOS with Cloud-Config
|
||
|
|
|
||
|
|
CoreOS allows you to configure machine parameters, launch systemd units on startup and more. Only a subset of [cloud-config functionality][cloud-config] is implemented. A set of custom parameters were added to the cloud-config format that are specific to CoreOS.
|
||
|
|
|
||
|
|
[cloud-config]: http://cloudinit.readthedocs.org/en/latest/topics/format.html#cloud-config-data
|
||
|
|
|
||
|
|
## Supported cloud-config Parameters
|
||
|
|
|
||
|
|
### ssh_authorized_keys
|
||
|
|
|
||
|
|
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`.
|
||
|
|
|
||
|
|
## Custom cloud-config Parameters
|
||
|
|
|
||
|
|
### coreos.etcd.discovery_url
|
||
|
|
|
||
|
|
The value of `coreos.etcd.discovery_url` will be used to discover the instance's etcd peers using the [etcd discovery protocol][disco-proto]. Usage of the [public discovery service][disco-service] is encouraged.
|
||
|
|
|
||
|
|
[disco-proto]: https://github.com/coreos/etcd/blob/master/Documentation/discovery-protocol.md
|
||
|
|
[disco-service]: http://discovery.etcd.io
|
||
|
|
|
||
|
|
### coreos.units
|
||
|
|
|
||
|
|
Arbitrary systemd units may be provided in the `coreos.units` attribute.
|
||
|
|
`coreos.units` is a list of objects with the following fields:
|
||
|
|
|
||
|
|
- **name**: string representing unit's name
|
||
|
|
- **runtime**: boolean indicating whether or not to persist the unit across reboots. This is analagous to the `--runtime` flag to `systemd enable`.
|
||
|
|
- **content**: plaintext string representing entire unit file
|
||
|
|
|
||
|
|
See docker example below.
|
||
|
|
|
||
|
|
## user-data Script
|
||
|
|
|
||
|
|
Simply set your user-data to a script where the first line is a shebang:
|
||
|
|
|
||
|
|
```
|
||
|
|
#!/bin/bash
|
||
|
|
|
||
|
|
echo 'Hello, world!'
|
||
|
|
```
|
||
|
|
|
||
|
|
## Examples
|
||
|
|
|
||
|
|
### Inject an SSH key, bootstrap etcd, and start fleet
|
||
|
|
```
|
||
|
|
#cloud-config
|
||
|
|
|
||
|
|
coreos:
|
||
|
|
etcd:
|
||
|
|
discovery_url: https://discovery.etcd.io/827c73219eeb2fa5530027c37bf18877
|
||
|
|
fleet:
|
||
|
|
autostart: yes
|
||
|
|
ssh_authorized_keys:
|
||
|
|
- ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC0g+ZTxC7weoIJLUafOgrm+h...
|
||
|
|
```
|
||
|
|
|
||
|
|
### Start a docker container on boot
|
||
|
|
|
||
|
|
```
|
||
|
|
#cloud-config
|
||
|
|
|
||
|
|
coreos:
|
||
|
|
units:
|
||
|
|
- name: docker-redis.service
|
||
|
|
content: |
|
||
|
|
[Unit]
|
||
|
|
Description=Redis container
|
||
|
|
Author=Me
|
||
|
|
After=docker.service
|
||
|
|
|
||
|
|
[Service]
|
||
|
|
Restart=always
|
||
|
|
ExecStart=/usr/bin/docker start -a redis_server
|
||
|
|
ExecStop=/usr/bin/docker stop -t 2 redis_server
|
||
|
|
|
||
|
|
[Install]
|
||
|
|
WantedBy=local.target
|
||
|
|
```
|