Cloud-Init file / User data file

AWS-User-Data

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#cloud-config
# cloud-init directives
# if script-user,always then the bash script defined below (userdata.txt) will be executed everytime
cloud_final_modules:
- [scripts-user, always]
runcmd:
 - [ mkdir, /test-cloudinit ]
write_files:
 - path: /test-cloudinit/cloud-init.txt
   content: Created by cloud-init

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#!/bin/bash
/bin/echo "Hello World." >> /tmp/sdksdfjsdlf
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cloud-config.yml

#cloud-config
# Add groups to the system.
groups:
  - group_name: [member1,member2]
# Add users to the system.
users:
 - default
 - name: User’s login name.
   gecos: User’s real name.
   primary_group: The primary group the user belongs to. If omitted, a new group is created under the user’s name.
   groups: Additional groups to which you want to add the user.
   selinux_user: The SELinux user for the user's login. If omitted, the system selects the default SELinux user.
   expiredate: 'year-month-day' - Data when the user’s account should be disabled.
   ssh_import_id: SSH IDs which you want to import.
   lock_passwd: Use true or false to define whether you want to lock the password to disable password login. By default, the value is set to true.
   inactive: 'x' - The number of days until the account is disabled after a password expires.
   passwd: The hash of the password you want to use.
   ssh_authorized_keys: Add keys to user’s authorized keys file:
      - <ssh pub key 1>
      - <ssh pub key 2>
   system: Use true or false to define the new user as a system user.
   sudo: Use sudo rule string(s) to define the user privileges. The user has no privileges by default, but it can accept one or multiple sudo rule strings. For example, add ALL=(ALL) NOPASSWD:ALL to give the user unrestricted access. To prevent sudo access, type: False.
   sudo: ['ALL=(ALL) NOPASSWD:ALL']
  - snapuser: Specify the email for your Ubuntu SSO account to allow snap to import a username and public keys into the system.
# Write out arbitrary files
write_files:
  path: The file path to which the content is added.
  content: The content you want to add to the path.
  owner: The user/group that has ownership. By default, the owner is root:root.
  permissions: The permission of the specified path, defined with the appropriate octal string. The default permission is ‘0644’.
  append: Use true or false to choose whether to append the specified content to an existing file if the path provided exists. The default value is false.
# Add yum repos
yum_repos:
  <repo_name>:
            baseurl: Repository URL.
            name: Repository name.
            enabled: true/false
            + any other repository configuration option
# Run commands at the boot time 
# In case we are on apt os
apt_update: true
apt_upgrade: true
packages:
  - nginx
  - rsync
  
bootcmd:
  - echo 192.168.1.130 us.archive.ubuntu.com >> /etc/hosts
  - [cloud-init-per, once, mymkfs, mkfs, /dev/vdb ]
# Run commands only the first time the instance boots
runcmd:
 - [ ls, -l, / ]
 - [ sh, -xc, "echo $(date) ': hello world!'" ]
 - [ sh, -c, echo "=========hello world'=========" ]
 - ls -l /root
 - sed -i -e '/^Port/s/^.*$/Port 4444/' /etc/ssh/sshd_config
 - sed -i -e '/^PermitRootLogin/s/^.*$/PermitRootLogin no/' /etc/ssh/sshd_config
 - restart ssh

ssh_keys:
  rsa_private: |
    -----BEGIN RSA PRIVATE KEY-----
    your_rsa_private_key
    -----END RSA PRIVATE KEY-----
  rsa_public: your_rsa_public_key
ssh_import_id: [user1, user2]

locale: What you want to configure as the system's locale.
locale_configfile: The path to the file where you want to write the locale configuration.  

preserve_hostname: Use true or false to set whether to preserve the host name or allow altering.
prefer_fqdn_over_hostname: Use true or false to set whether to force the use of FQDN in all distros.
fqdn: FQDN
hostname: FQDN/hostname

## To debug check the following log files
# /var/log/cloud-init.log
# /var/log/cloud-init-output.log