cloudinit是專為雲環境中虛擬機器的初始化而開發的工具，它從各種資料來源讀取相關資料並據此對虛擬機器進行配置。常見的資料來源包括：雲平臺的metadata服務、ConfigDrive等，常見的配置包括：設定虛擬機器的hostname、hosts檔案、設定使用者名稱密碼、更新apt －get的本地快取、調整檔案系統的大小（注意不是調整分割槽的大小）等。

本文在openstack下進行測試。

（1）安裝
centos 6.4和ubuntu server 12.04的官方源中已經包含cloudinit，直接採用yum 或者 apt -get安裝即可
原始碼地址：https://launchpad.net/cloud-init

（2）配置
配置檔案/etc/cloud/cloud.cfg

user: root                            
disable_root: 0
manage_etc_hosts: True
preserve_hostname: False

cloud_init_modules:
 - bootcmd
 - resizefs
 - set_hostname
 - update_hostname
 - update_etc_hosts
 - ca-certs
 - rsyslog
 - ssh

cloud_config_modules:
 - mounts
 - ssh-import-id
 - locale
 - set-passwords
 - grub-dpkg
 - landscape
 - timezone
 - puppet
 - chef
 - salt-minion
 - mcollective
 - disable-ec2-metadata
 - runcmd
 - byobu

cloud_final_modules:
 - rightscale_userdata
 - scripts-per-once
 - scripts-per-boot
 - scripts-per-instance
 - scripts-user
 - keys-to-console
 - phone-home
 - final-message

配置檔案大致分為兩部分，開頭的變數/引數定義部分、後邊要執行的模組列表（包括三大類cloud_init_modules、cloud_config_modules、cloud_final_modules）。

各模組在執行時，會根據之前定義的變數/引數的值，配置虛擬機器的狀態。

這裡舉一個簡單的例子，update_etc_hosts模組（原始檔：/usr/lib/python2.7/dist-packages/cloudinit/CloudConfig/cc_update_etc_hosts.py）

顧名思義，該模組用來設定主機的hosts檔案，其中就用到了hostname、fqdn、manage_etc_hosts等變數的值。模組首先嚐試從cloudinit的配置檔案中讀取這些變數的值，如果沒有定義，則嘗試從其他的資料來源中獲取變數的值，例如對於openstac來講，可以從metadata service（

（3）執行流程

cloudinit會在虛擬機器啟動的過程中分四個階段執行，按照時間順序分為：cloud-init-local, cloud-init, cloud-config, cloud-final，例如對於centos：

cloud-init-local階段主要是執行本地的一些初始化指令碼（快取下來的指令碼？？）

cloud-init階段執行配置檔案中名為cloud_init_modules下的所有模組，如果模組列表為空，則什麼都不執行。其他兩個階段類似，就不介紹了。

分階段執行的必要性在於，有些模組的執行對系統當前的狀態會有要求（比如網路ready、檔案系統掛載over），因此cloudinit抽象出了四個階段，編寫自己的初始化模組時可以根據情況歸入不同的階段。

另外，模組有多種執行模式，包括per-once、per-instance、per-always，對於模式為per-once的模組，一旦執行完畢會在一個名為sem的目錄中建立一個訊號檔案，從而防止模組的在下次啟動時重複執行。

（4）實戰

控制cloudinit配置行為的方式有兩種：cloudinit的配置檔案(/etc/cloud/cloud.cfg)和資料來源（如openstack及ec2中的userdata）

這裡我們採用Mime Mult Part Archive的檔案格式，包含了四種具體的格式（cloud-config、include file、boothook、以及userscript）

Content-Type: multipart/mixed; boundary="===============2197920354430400835=="
MIME-Version: 1.0

--===============2197920354430400835==
Content-Type: text/cloud-config; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="cloudconfig.txt"

#cloud-config
runcmd:
 - touch /root/cloudconfig
 - source: "ppa:smoser/ppa"

--===============2197920354430400835==
Content-Type: text/x-include-url; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="includefile.txt"

# these urls will be read pulled in if they were part of user-data
# comments are allowed.  The format is one url per line
http://www.ubuntu.com/robots.txt

--===============2197920354430400835==
Content-Type: text/cloud-boothook; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="boothook.txt"

#!/bin/sh
echo "Hello World!"

--===============2197920354430400835==
Content-Type: text/x-shellscript; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="userscript.txt"

#!/usr/bin/perl
print "This is a user script (rc.local)\n"

--===============2197920354430400835==--

cloudinit從資料來源中拿到該userdata後，首先會對其進行切分，並分別供各模組處理。例如抽取cloud-config部分，如：

userscript部分

cloudinit中所有的模組都放在/usr/lib/python2.7/dist-packages/cloudinit/CloudConfig/下，具體用法可以直接研究程式碼或者參考http://cloudinit.readthedocs.org/en/latest/index.html

這裡需要特別提到的一個模組是scripts-user，該模組負責執行userdata中的user scripts內容以及其他模組（如runcmd）生成的指令碼，因此cloudinit的配置檔案將其放在了cloud_final_modules階段的近乎最後。

（5）思考

為了解決雲平臺中的初始化問題，人們設計了cloudinit，它駐留在虛擬機器中，隨機啟動，根據配置檔案和雲平臺提供的userdata進行相關配置，目前支援多種檔案內容格式，包括單純的使用者指令碼，引入的cloud-config、include file等。cloudinit其實就是駐留在虛擬機器中的一個agent，唯一不同的是它僅僅在系統啟動時執行，不會常駐系統。假稍作修改，cloudinit其實也可以作為虛擬機器的agent，能做的就不僅僅是初始化了。例如，可以批量配置虛擬機器（安裝軟體，更新系統，修改密碼等），可以作為監控的agent等。

cloudinit的典型配置：http://xebia-france.googlecode.com/svn/training/xebia-spring-travel/trunk/xebia-spring-travel-amazon-aws/src/main/scripts/cloud-config-sample.txt

#cloud-config
# Update apt database on first boot
# (ie run apt-get update)
#
# Default: true
#
apt_update: false

# Upgrade the instance on first boot
# (ie run apt-get upgrade)
#
# Default: false
#
apt_upgrade: true

# Add apt repositories
#
# Default: auto select based on cloud metadata
#  in ec2, the default is <region>.archive.ubuntu.com
apt_mirror: http://us.archive.ubuntu.com/ubuntu/

# Preserve existing /etc/apt/sources.list
# Default: overwrite sources_list with mirror.  If this is true
# then apt_mirror above will have no effect
apt_preserve_sources_list: true

apt_sources:
 - source: "deb http://ppa.launchpad.net/byobu/ppa/ubuntu karmic main"
   keyid: F430BBA5 # GPG key ID published on a key server
   filename: byobu-ppa.list

 # PPA shortcut:
 #  * Setup correct apt sources.list line
 #  * Import the signing key from LP
 #
 #  See https://help.launchpad.net/Packaging/PPA for more information
 #  this requires 'add-apt-repository'
 - source: "ppa:smoser/ppa"    # Quote the string

 # Custom apt repository:
 #  * all that is required is 'source'
 #  * Creates a file in /etc/apt/sources.list.d/ for the sources list entry
 #  * [optional] Import the apt signing key from the keyserver 
 #  * Defaults:
 #    + keyserver: keyserver.ubuntu.com
 #    + filename: cloud_config_sources.list
 #
 #    See sources.list man page for more information about the format
 - source: deb http://archive.ubuntu.com/ubuntu karmic-backports main universe multiverse restricted

 # sources can use $MIRROR and $RELEASE and they will be replaced
 # with the local mirror for this cloud, and the running release
 # the entry below would be possibly turned into:
 # - source: deb http://us-east-1.ec2.archive.ubuntu.com/ubuntu natty multiverse
 - source: deb $MIRROR $RELEASE multiverse

 # this would have the same end effect as 'ppa:byobu/ppa'
 - source: "deb http://ppa.launchpad.net/byobu/ppa/ubuntu karmic main"
   keyid: F430BBA5 # GPG key ID published on a key server
   filename: byobu-ppa.list

 # Custom apt repository:
 #  * The apt signing key can also be specified
 #    by providing a pgp public key block
 #  * Providing the PBG key here is the most robust method for
 #    specifying a key, as it removes dependency on a remote key server

 - source: deb http://ppa.launchpad.net/alestic/ppa/ubuntu karmic main 
   key: | # The value needs to start with -----BEGIN PGP PUBLIC KEY BLOCK-----
      -----BEGIN PGP PUBLIC KEY BLOCK-----
      Version: SKS 1.0.10

      mI0ESpA3UQEEALdZKVIMq0j6qWAXAyxSlF63SvPVIgxHPb9Nk0DZUixn+akqytxG4zKCONz6
      qLjoBBfHnynyVLfT4ihg9an1PqxRnTO+JKQxl8NgKGz6Pon569GtAOdWNKw15XKinJTDLjnj
      9y96ljJqRcpV9t/WsIcdJPcKFR5voHTEoABE2aEXABEBAAG0GUxhdW5jaHBhZCBQUEEgZm9y
      IEFsZXN0aWOItgQTAQIAIAUCSpA3UQIbAwYLCQgHAwIEFQIIAwQWAgMBAh4BAheAAAoJEA7H
      5Qi+CcVxWZ8D/1MyYvfj3FJPZUm2Yo1zZsQ657vHI9+pPouqflWOayRR9jbiyUFIn0VdQBrP
      t0FwvnOFArUovUWoKAEdqR8hPy3M3APUZjl5K4cMZR/xaMQeQRZ5CHpS4DBKURKAHC0ltS5o
      uBJKQOZm5iltJp15cgyIkBkGe8Mx18VFyVglAZey
      =Y2oI
      -----END PGP PUBLIC KEY BLOCK-----

# Install additional packages on first boot
#
# Default: none
#
# if packages are specified, this apt_update will be set to true
#
packages:
 - pwgen
 - pastebinit

# set up mount points
# 'mounts' contains a list of lists
#  the inner list are entries for an /etc/fstab line
#  ie : [ fs_spec, fs_file, fs_vfstype, fs_mntops, fs-freq, fs_passno ]
#
# default:
# mounts:
#  - [ ephemeral0, /mnt ]
#  - [ swap, none, swap, sw, 0, 0 ]
#
# in order to remove a previously listed mount (ie, one from defaults)
# list only the fs_spec.  For example, to override the default, of
# mounting swap:
# - [ swap ]
# or
# - [ swap, null ]
#
# - if a device does not exist at the time, an entry will still be
#   written to /etc/fstab.
# - '/dev' can be ommitted for device names that begin with: xvd, sd, hd, vd
# - if an entry does not have all 6 fields, they will be filled in
#   with values from 'mount_default_fields' below.
#
# Note, that you should set 'nobootwait' (see man fstab) for volumes that may
# not be attached at instance boot (or reboot)
#
mounts:
 - [ ephemeral0, /mnt, auto, "defaults,noexec" ]
 - [ sdc, /opt/data ]
 - [ xvdh, /opt/data, "auto", "defaults,nobootwait", "0", "0" ]
 - [ dd, /dev/zero ]

# mount_default_fields
# These values are used to fill in any entries in 'mounts' that are not
# complete.  This must be an array, and must have 7 fields.
mount_default_fields: [ None, None, "auto", "defaults,nobootwait", "0", "2" ]

# add each entry to ~/.ssh/authorized_keys for the configured user
ssh_authorized_keys:
  - ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAGEA3FSyQwBI6Z+nCSjUUk8EEAnnkhXlukKoUPND/RRClWz2s5TCzIkd3Ou5+Cyz71X0XmazM3l5WgeErvtIwQMyT1KjNoMhoJMrJnWqQPOt5Q8zWd9qG7PBl9+eiH5qV7NZ [email protected]
  - ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA3I7VUf2l5gSn5uavROsc5HRDpZdQueUq5ozemNSj8T7enqKHOEaFoU2VoPgGEWC9RyzSQVeyD6s7APMcE82EtmW4skVEgEGSbDc1pvxzxtchBj78hJP6Cf5TCMFSXw+Fz5rF1dR23QDbN1mkHs7adr8GW4kSWqU7Q7NDwfIrJJtO7Hi42GyXtvEONHbiRPOe8stqUly7MvUoN+5kfjBM8Qqpfl2+FNhTYWpMfYdPUnE7u536WqzFmsaqJctz3gBxH9Ex7dFtrxR4qiqEr9Qtlu3xGn7Bw07/+i1D+ey3ONkZLN+LQ714cgj8fRS4Hj29SCmXp5Kt5/82cD/VN3NtHw== [email protected]

# Send pre-generated ssh private keys to the server
# If these are present, they will be written to /etc/ssh and
# new random keys will not be generated
ssh_keys:
  rsa_private: |
    -----BEGIN RSA PRIVATE KEY-----
    MIIBxwIBAAJhAKD0YSHy73nUgysO13XsJmd4fHiFyQ+00R7VVu2iV9Qcon2LZS/x
    1cydPZ4pQpfjEha6WxZ6o8ci/Ea/w0n+0HGPwaxlEG2Z9inNtj3pgFrYcRztfECb
    1j6HCibZbAzYtwIBIwJgO8h72WjcmvcpZ8OvHSvTwAguO2TkR6mPgHsgSaKy6GJo
    PUJnaZRWuba/HX0KGyhz19nPzLpzG5f0fYahlMJAyc13FV7K6kMBPXTRR6FxgHEg
    L0MPC7cdqAwOVNcPY6A7AjEA1bNaIjOzFN2sfZX0j7OMhQuc4zP7r80zaGc5oy6W
    p58hRAncFKEvnEq2CeL3vtuZAjEAwNBHpbNsBYTRPCHM7rZuG/iBtwp8Rxhc9I5w
    ixvzMgi+HpGLWzUIBS+P/XhekIjPAjA285rVmEP+DR255Ls65QbgYhJmTzIXQ2T9
    luLvcmFBC6l35Uc4gTgg4ALsmXLn71MCMGMpSWspEvuGInayTCL+vEjmNBT+FAdO
    W7D4zCpI43jRS9U06JVOeSc9CDk2lwiA3wIwCTB/6uc8Cq85D9YqpM10FuHjKpnP
    REPPOyrAspdeOAV+6VKRavstea7+2DZmSUgE
    -----END RSA PRIVATE KEY-----

  rsa_public: ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAGEAoPRhIfLvedSDKw7XdewmZ3h8eIXJD7TRHtVW7aJX1ByifYtlL/HVzJ09nilCl+MSFrpbFnqjxyL8Rr/DSf7QcY/BrGUQbZn2Kc22PemAWthxHO18QJvWPocKJtlsDNi3 [email protected]

  dsa_private: |
    -----BEGIN DSA PRIVATE KEY-----
    MIIBuwIBAAKBgQDP2HLu7pTExL89USyM0264RCyWX/CMLmukxX0Jdbm29ax8FBJT
    pLrO8TIXVY5rPAJm1dTHnpuyJhOvU9G7M8tPUABtzSJh4GVSHlwaCfycwcpLv9TX
    DgWIpSj+6EiHCyaRlB1/CBp9RiaB+10QcFbm+lapuET+/Au6vSDp9IRtlQIVAIMR
    8KucvUYbOEI+yv+5LW9u3z/BAoGBAI0q6JP+JvJmwZFaeCMMVxXUbqiSko/P1lsa
    LNNBHZ5/8MOUIm8rB2FC6ziidfueJpqTMqeQmSAlEBCwnwreUnGfRrKoJpyPNENY
    d15MG6N5J+z81sEcHFeprryZ+D3Ge9VjPq3Tf3NhKKwCDQ0240aPezbnjPeFm4mH
    bYxxcZ9GAoGAXmLIFSQgiAPu459rCKxT46tHJtM0QfnNiEnQLbFluefZ/yiI4DI3
    8UzTCOXLhUA7ybmZha+D/csj15Y9/BNFuO7unzVhikCQV9DTeXX46pG4s1o23JKC
    /QaYWNMZ7kTRv+wWow9MhGiVdML4ZN4XnifuO5krqAybngIy66PMEoQCFEIsKKWv
    99iziAH0KBMVbxy03Trz
    -----END DSA PRIVATE KEY-----

  dsa_public: ssh-dss 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 [email protected]

# remove access to the ec2 metadata service early in boot via null route
#  the null route can be removed (by root) with:
#    route del -host 169.254.169.254 reject
# default: false (service available)
disable_ec2_metadata: true

# run commands
# default: none
# runcmd contains a list of either lists or a string
# each item will be executed in order at rc.local like level with
# output to the console
# - if the item is a list, the items will be properly executed as if
#   passed to execve(3) (with the first arg as the command).
# - if the item is a string, it will be simply written to the file and
#   will be interpreted by 'sh'
#
# Note, that the list has to be proper yaml, so you have to escape
# any characters yaml would eat (':' can be problematic)
runcmd:
 - [ ls, -l, / ]
 - [ sh, -xc, "echo $(date) ': hello world!'" ]
 - [ sh, -c, echo "=========hello world'=========" ]
 - ls -l /root
 - [ wget, "http://slashdot.org", -O, /tmp/index.html ]

# boot commands
# default: none
# this is very similar to runcmd above, but commands run very early
# in the boot process, only slightly after a 'boothook' would run.
# bootcmd should really only be used for things that could not be
# done later in the boot process.  bootcmd is very much like
# boothook, but possibly with more friendly
bootcmd:
 - echo 192.168.1.130 us.archive.ubuntu.com > /etc/hosts

# cloud_config_modules:
# default:
# cloud_config_modules:
# - mounts
# - ssh
# - apt-update-upgrade
# - puppet
# - updates-check
# - disable-ec2-metadata
# - runcmd
#
# This is an array of arrays or strings.
# if item is a string, then it is read as a module name
# if the item is an array it is of the form:
#   name, frequency, arguments
# where 'frequency' is one of:
#   once-per-instance
#   always
# a python file in the CloudConfig/ module directory named 
# cc_<name>.py
# example:
cloud_config_modules:
 - mounts
 - ssh-import-id
 - ssh
 - grub-dpkg
 - [ apt-update-upgrade, always ]
 - puppet
 - updates-check
 - disable-ec2-metadata
 - runcmd
 - byobu

# ssh_import_id: [ user1, user2 ]
# ssh_import_id will feed the list in that variable to
#  ssh-import-id, so that public keys stored in launchpad
#  can easily be imported into the configured user
# This can be a single string ('smoser') or a list ([smoser, kirkland])
ssh_import_id: [smoser]

# Provide debconf answers
#
# See debconf-set-selections man page.
#
# Default: none
# 
debconf_selections: |     # Need to perserve newlines
        # Force debconf priority to critical.
        debconf debconf/priority select critical

        # Override default frontend to readline, but allow user to select.
        debconf debconf/frontend select readline
        debconf debconf/frontend seen false

# manage byobu defaults
# byobu_by_default:
#   'user' or 'enable-user': set byobu 'launch-by-default' for the default user
#   'system' or 'enable-system' or 'enable':
#      enable 'launch-by-default' for all users, do not modify default user
#   'disable': disable both default user and system
#   'disable-system': disable system
#   'disable-user': disable for default user
#   not-set: no changes made
byobu_by_default: system

# disable ssh access as root.
# if you want to be able to ssh in to the system as the root user
# rather than as the 'ubuntu' user, then you must set this to false
# default: true
disable_root: false

# disable_root_opts: the value of this variable will prefix the
# respective key in /root/.ssh/authorized_keys if disable_root is true
# see 'man authorized_keys' for more information on what you can do here
#
# The string '$USER' will be replaced with the username of the default user
#
# disable_root_opts: no-port-forwarding,no-agent-forwarding,no-X11-forwarding,command="echo 'Please login as the user \"$USER\" rather than the user \"root\".';echo;sleep 10"

# set the locale to a given locale
# default: en_US.UTF-8
locale: en_US.UTF-8

# add entries to rsyslog configuration
# The first occurance of a given filename will truncate. 
# subsequent entries will append.
# if value is a scalar, its content is assumed to be 'content', and the
# default filename is used.
# if filename is not provided, it will default to 'rsylog_filename'
# if filename does not start with a '/', it will be put in 'rsyslog_dir'
# rsyslog_dir default: /etc/rsyslog.d
# rsyslog_filename default: 20-cloud-config.conf
rsyslog:
 - ':syslogtag, isequal, "[CLOUDINIT]" /var/log/cloud-foo.log'
 - content: "*.*   @@192.0.2.1:10514"
 - filename: 01-examplecom.conf
   content: |
   *.*   @@syslogd.example.com

# resize_rootfs should the / filesytem be resized on first boot
# this allows you to launch an instance with a larger disk / partition
# and have the instance automatically grow / to accomoddate it
# set to 'False' to disable
resize_rootfs: True

# if hostname is set, cloud-init will set the system hostname 
# appropriately to its value
# if not set, it will set hostname from the cloud metadata
# default: None

# final_message
# default: cloud-init boot finished at $TIMESTAMP. Up $UPTIME seconds
# this message is written by cloud-final when the system is finished
# its first boot
final_message: "The system is finally up, after $UPTIME seconds"

# configure where output will go
# 'output' entry is a dict with 'init', 'config', 'final' or 'all'
# entries.  Each one defines where 
#  cloud-init, cloud-config, cloud-config-final or all output will go
# each entry in the dict can be a string, list or dict.
#  if it is a string, it refers to stdout and stderr
#  if it is a list, entry 0 is stdout, entry 1 is stderr
#  if it is a dict, it is expected to have 'output' and 'error' fields
# default is to write to console only
# the special entry "&1" for an error means "same location as stdout"
#  (Note, that '&1' has meaning in yaml, so it must be quoted)
output:
 init: "> /var/log/my-cloud-init.log"
 config: [ ">> /tmp/foo.out", "> /tmp/foo.err" ]
 final:
   output: "| tee /tmp/final.stdout | tee /tmp/bar.stdout"
   error: "&1"

# phone_home: if this dictionary is present, then the phone_home
# cloud-config module will post specified data back to the given
# url
# default: none
# phone_home:
#  url: http://my.foo.bar/$INSTANCE/
#  post: all
#  tries: 10
#
phone_home:
 url: http://my.example.com/$INSTANCE_ID/
 post: [ pub_key_dsa, pub_key_rsa, instance_id ]

# timezone: set the timezone for this instance
# the value of 'timezone' must exist in /usr/share/zoneinfo
timezone: US/Eastern

# def_log_file and syslog_fix_perms work together
# if 
# - logging is set to go to a log file 'L' both with and without syslog
# - and 'L' does not exist
# - and syslog is configured to write to 'L'
# then 'L' will be initially created with root:root ownership (during
# cloud-init), and then at cloud-config time (when syslog is available)
# the syslog daemon will be unable to write to the file.
# 
# to remedy this situation, 'def_log_file' can be set to a filename
# and syslog_fix_perms to a string containing "<user>:<group>"
#
# the default values are '/var/log/cloud-init.log' and 'syslog:adm'
# the value of 'def_log_file' should match what is configured in logging
# if either is empty, then no change of ownership will be done
def_log_file: /var/log/my-logging-file.log
syslog_fix_perms: syslog:root

# you can set passwords for a user or multiple users
# this is off by default.
# to set the default user's password, use the 'password' option.
# if set, to 'R' or 'RANDOM', then a random password will be
# generated and written to stdout (the console)
# password: passw0rd
#
# also note, that this will expire the password, forcing a change
# on first login. If you do not want to expire, see 'chpasswd' below.
#
# By default in the UEC images password authentication is disabled
# Thus, simply setting 'password' as above will only allow you to login
# via the console.
#
# in order to enable password login via ssh you must set
# 'ssh_pwauth'.
# If it is set, to 'True' or 'False', then sshd_config will be updated
# to ensure the desired function.  If not set, or set to '' or 'unchanged'
# then sshd_config will not be updated.
# ssh_pwauth: True
#
# there is also an option to set multiple users passwords, using 'chpasswd'
# That looks like the following, with 'expire' set to 'True' by default.
# to not expire users passwords, set 'expire' to 'False':
# chpasswd:
#  list: |
#    user1:password1
#    user2:RANDOM
#  expire: True
# ssh_pwauth: [ True, False, "" or "unchanged" ]
#
# So, a simple working example to allow login via ssh, and not expire
# for the default user would look like:
password: passw0rd
chpasswd: { expire: False }
ssh_pwauth: True

# manual cache clean.
#  By default, the link from /var/lib/cloud/instance to
#  the specific instance in /var/lib/cloud/instances/ is removed on every
#  boot.  The cloud-init code then searches for a DataSource on every boot
#  if your DataSource will not be present on every boot, then you can set
#  this option to 'True', and maintain (remove) that link before the image
#  will be booted as a new instance.
# default is False
manual_cache_clean: False

# if you wish to have /etc/hosts written from /etc/cloud/templates/hosts.tmpl
# on a per-always basis (to account for ebs stop/start), then set
# manage_etc_hosts to True. The default is 'False'
manage_etc_hosts: False

# When cloud-init is finished running including having run 
# cloud_init_modules, then it will run this command.  The default
# is to emit an upstart signal as shown below.  If the value is a
# list, it will be passed to Popen.  If it is a string, it will be
# invoked through 'sh -c'.
# 
# default value:
# cc_ready_cmd: [ initctl, emit, cloud-config, CLOUD_CFG=/var/lib/instance//cloud-config.txt ]
# example:
# cc_ready_cmd: [ sh, -c, 'echo HI MOM > /tmp/file' ]