#cloud-config
write_files:
-   content: blah
    path: /etc/blah.ini
    permissions: 493

system_info:
 package_mirrors:
   - arches: [i386, amd64, blah]
     failsafe:
      primary: http://my.archive.mydomain.com/ubuntu
      security: http://my.security.mydomain.com/ubuntu
     search:
      primary: []
      security: []