79 lines
2.5 KiB
Markdown
79 lines
2.5 KiB
Markdown
# coreos-cloudinit [](https://travis-ci.org/coreos/coreos-cloudinit)
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coreos-cloudinit enables a user to customize CoreOS machines by providing either a cloud-config document or an executable script through user-data.
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## Configuration with cloud-config
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A subset of the [official cloud-config spec][official-cloud-config] is implemented by coreos-cloudinit.
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Additionally, several [CoreOS-specific options][custom-cloud-config] have been implemented to support interacting with unit files, bootstrapping etcd clusters, and more.
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All supported cloud-config parameters are [documented here][all-cloud-config].
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[official-cloud-config]: http://cloudinit.readthedocs.org/en/latest/topics/format.html#cloud-config-data
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[custom-cloud-config]: https://github.com/coreos/coreos-cloudinit/blob/master/Documentation/cloud-config.md#coreos-parameters
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[all-cloud-config]: https://github.com/coreos/coreos-cloudinit/tree/master/Documentation/cloud-config.md
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The following is an example cloud-config document:
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```
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#cloud-config
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coreos:
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units:
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- name: etcd.service
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command: start
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users:
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- name: core
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passwd: $1$allJZawX$00S5T756I5PGdQga5qhqv1
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write_files:
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- path: /etc/resolv.conf
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content: |
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nameserver 192.0.2.2
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nameserver 192.0.2.3
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```
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## Executing a Script
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coreos-cloudinit supports executing user-data as a script instead of parsing it as a cloud-config document.
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Make sure the first line of your user-data is a shebang and coreos-cloudinit will attempt to execute it:
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```
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#!/bin/bash
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echo 'Hello, world!'
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```
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## user-data Field Substitution
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coreos-cloudinit will replace the following set of tokens in your user-data with system-generated values.
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| Token | Description |
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| ------------- | ----------- |
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| $public_ipv4 | Public IPv4 address of machine |
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| $private_ipv4 | Private IPv4 address of machine |
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These values are determined by CoreOS based on the given provider on which your machine is running.
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Read more about provider-specific functionality in the [CoreOS OEM documentation][oem-doc].
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[oem-doc]: https://coreos.com/docs/sdk-distributors/distributors/notes-for-distributors/
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For example, submitting the following user-data...
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```
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#cloud-config
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coreos:
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etcd:
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addr: $public_ipv4:4001
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peer-addr: $private_ipv4:7001
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```
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...will result in this cloud-config document being executed:
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```
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#cloud-config
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coreos:
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etcd:
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addr: 203.0.113.29:4001
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peer-addr: 192.0.2.13:7001
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``` |