AWS CloudFormation (init)

Overview

• Installing and configuring software using CF

 AWS::CloudFormation::Init

• It is a special key put into template metadata
  • Either on the template or individual resource level
• Defines instructions for cfn-init python script
• Sections
  
  • ConfigSets
    
    • Specify multiple "config" keys and allows to change order of execution (e.g. config1, config2)
    • config keys may be embedded in one another
  • Commands
    • Execute Bash/cmd.exe command 
      
      • Parameters: command, env, cwd (working directory), test, ignoreErrors, waitAfterCompletion (windows only: used for rebooting)
  • Files
    • Create files
      • Parameters: content, source (XOR with content), group, owner, mode
    • Supports Mustache templates (require context parameter)
  • Packages
    • Download and install packages
      • Linux: yum, rpm, apt, rubygems, python
      • Windows: msi
    • May specify version
  • Services
    • Enable/Disable services
      • Linux: syvinit
      • Windows: SCM
    • Parameters: files (restart service if touched), packages, ensureRunning, enabled
  • Sources
    • Download archive and unpack it to target directory
  • Groups
  •  Users
    • Create users
      • Parameters: uid, groups, homedir

cfn-init

• Default order
  •  packages, groups, users, sources, files, commands, services
• Injected via "UserData" property on EC2 instance

  • "/opt/aws/bin/cfn-init"