b89ddae983
Implement unit.command
200 lines
7.0 KiB
Markdown
200 lines
7.0 KiB
Markdown
# Customize with Cloud-Config
|
|
|
|
CoreOS allows you to configure networking, create users, launch systemd units on startup and more. We've designed our implementation to allow the same cloud-config file to work across all of our supported platforms.
|
|
|
|
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. An example file containing all available options can be found at the bottom of this page.
|
|
|
|
[cloud-config]: http://cloudinit.readthedocs.org/en/latest/topics/format.html#cloud-config-data
|
|
|
|
## CoreOS Parameters
|
|
|
|
### coreos.etcd
|
|
|
|
The `coreos.etcd.*` options are translated to a partial systemd unit acting as an etcd configuration file.
|
|
`coreos-cloudinit` will also replace the strings `$private_ipv4` and `$public_ipv4` with the values generated by CoreOS based on a given provider.
|
|
|
|
For example, the following cloud-config document...
|
|
|
|
```
|
|
#cloud-config
|
|
|
|
coreos:
|
|
etcd:
|
|
name: node001
|
|
discovery: https://discovery.etcd.io/3445fa65423d8b04df07f59fb40218f8
|
|
addr: $public_ipv4:4001
|
|
peer-addr: $private_ipv4:7001
|
|
```
|
|
|
|
...will generate a systemd unit drop-in like this:
|
|
|
|
```
|
|
[Service]
|
|
Environment="ETCD_NAME=node001""
|
|
Environment="ETCD_DISCOVERY=https://discovery.etcd.io/3445fa65423d8b04df07f59fb40218f8"
|
|
Environment="ETCD_ADDR=203.0.113.29:4001"
|
|
Environment="ETCD_PEER_ADDR=192.0.2.13:7001"
|
|
```
|
|
|
|
For more information about the available configuration options, see the [etcd documentation][etcd-config].
|
|
Note that hyphens in the coreos.etcd.* keys are mapped to underscores.
|
|
|
|
[etcd-config]: https://github.com/coreos/etcd/blob/master/Documentation/configuration.md
|
|
|
|
### 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. Required.
|
|
- **runtime**: Boolean indicating whether or not to persist the unit across reboots. This is analagous to the `--runtime` argument to `systemd enable`. Default value is false.
|
|
- **content**: Plaintext string representing entire unit file. If no value is provided, the unit is assumed to exist already.
|
|
- **command**: Command to execute on unit: start, stop, reload, restart, try-restart, reload-or-restart, reload-or-try-restart. Default value is restart.
|
|
|
|
**NOTE:** The command field is ignored for all network, netdev, and link units. The systemd-networkd.service unit will be restarted in their place.
|
|
|
|
##### Examples
|
|
|
|
Write a unit to disk, automatically starting it.
|
|
|
|
```
|
|
#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
|
|
```
|
|
|
|
Start the builtin `etcd` and `fleet` services:
|
|
|
|
```
|
|
# cloud-config
|
|
|
|
coreos:
|
|
units:
|
|
- name: etcd.service
|
|
command: start
|
|
- name: fleet.service
|
|
command: start
|
|
|
|
|
|
## 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`.
|
|
|
|
```
|
|
#cloud-config
|
|
|
|
ssh_authorized_keys:
|
|
- ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC0g+ZTxC7weoIJLUafOgrm+h...
|
|
```
|
|
|
|
### hostname
|
|
|
|
The provided value will be used to set the system's hostname.
|
|
This is the local part of a fully-qualified domain name (i.e. `foo` in `foo.example.com`).
|
|
|
|
```
|
|
#cloud-config
|
|
|
|
hostname: coreos1
|
|
```
|
|
|
|
### users
|
|
|
|
Add or modify users with the `users` directive by providing a list of user objects, each consisting of the following fields.
|
|
Each field is optional and of type string unless otherwise noted.
|
|
All but the `passwd` and `ssh-authorized-keys` fields will be ignored if the user already exists.
|
|
|
|
- **name**: Required. Login name of user
|
|
- **gecos**: GECOS comment of user
|
|
- **passwd**: Hash of the password to use for this user
|
|
- **homedir**: User's home directory. Defaults to /home/<name>
|
|
- **no-create-home**: Boolean. Skip home directory creation.
|
|
- **primary-group**: Default group for the user. Defaults to a new group created named after the user.
|
|
- **groups**: Add user to these additional groups
|
|
- **no-user-group**: Boolean. Skip default group creation.
|
|
- **ssh-authorized-keys**: List of public SSH keys to authorize for this user
|
|
- **coreos-ssh-import-github**: Authorize SSH keys from Github user
|
|
- **system**: Create the user as a system user. No home directory will be created.
|
|
- **no-log-init**: Boolean. Skip initialization of lastlog and faillog databases.
|
|
|
|
The following fields are not yet implemented:
|
|
|
|
- **inactive**: Deactivate the user upon creation
|
|
- **lock-passwd**: Boolean. Disable password login for user
|
|
- **sudo**: Entry to add to /etc/sudoers for user. By default, no sudo access is authorized.
|
|
- **selinux-user**: Corresponding SELinux user
|
|
- **ssh-import-id**: Import SSH keys by ID from Launchpad.
|
|
|
|
```
|
|
#cloud-config
|
|
|
|
users:
|
|
- name: elroy
|
|
passwd: $6$5s2u6/jR$un0AvWnqilcgaNB3Mkxd5yYv6mTlWfOoCYHZmfi3LDKVltj.E8XNKEcwWm...
|
|
groups:
|
|
- staff
|
|
- docker
|
|
ssh-authorized-keys:
|
|
- ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC0g+ZTxC7weoIJLUafOgrm+h...
|
|
```
|
|
|
|
#### Generating a password hash
|
|
|
|
If you choose to use a password instead of an SSH key, generating a safe hash is extremely important to the security of your system. Simplified hashes like md5crypt are trivial to crack on modern GPU hardware. Here are a few ways to generate secure hashes:
|
|
|
|
```
|
|
# On Debian/Ubuntu (via the package "whois")
|
|
mkpasswd --method=SHA-512 --rounds=4096
|
|
|
|
# OpenSSL (note: this will only make md5crypt. While better than plantext it should not be considered fully secure)
|
|
openssl passwd -1
|
|
|
|
# Python (change password and salt values)
|
|
python -c "import crypt, getpass, pwd; print crypt.crypt('password', '\$6\$SALT\$')"
|
|
|
|
# Perl (change password and salt values)
|
|
perl -e 'print crypt("password","\$6\$SALT\$") . "\n"'
|
|
```
|
|
|
|
Using a higher number of rounds will help create more secure passwords, but given enough time, password hashes can be reversed. On most RPM based distributions there is a tool called mkpasswd available in the `expect` package, but this does not handle "rounds" nor advanced hashing algorithms.
|
|
|
|
### write_files
|
|
|
|
Inject an arbitrary set of files to the local filesystem.
|
|
Provide a list of objects with the following attributes:
|
|
|
|
- **path**: Absolute location on disk where contents should be written
|
|
- **content**: Data to write at the provided `path`
|
|
- **permissions**: String representing file permissions in octal notation (i.e. '0644')
|
|
- **owner**: User and group that should own the file written to disk. This is equivalent to the `<user>:<group>` argument to `chown <user>:<group> <path>`.
|
|
|
|
## user-data Script
|
|
|
|
Simply set your user-data to a script where the first line is a shebang:
|
|
|
|
```
|
|
#!/bin/bash
|
|
|
|
echo 'Hello, world!'
|
|
```
|