Cloud Init is a package that handles early initialization of cloud instances. It retrieves instance metadata like the server name and IP from the cloud provider. It then runs scripts and modules to configure the server, such as adding users, installing packages, and configuring services. It works across many Linux distributions and retrieves data through metadata services, config drives, or ISO images depending on the cloud platform. Administrators can write their own modules to customize the initialization and troubleshoot using logs and files stored in /var/lib/cloud.

1. CLOUD INIT
Sri Rajan

2. Intro
• The defacto multi-distribution package that
handles early initialization of a cloud instance
– As described by Ubuntu
• Early stage configuration of servers (think rc.local)

3. Intro
• No install required*
• Cloud Platform support required
• Works on most common Linux distros

4. Windows?
• CloudBaseInit
• Windows agents (Apache license)
• Similar functionality
• Next Time…

5. How does it work?
• Cloud Server
• Data Source
• EC2 (magic ip)
• Metadata service (OpenStack)
• Config Drive
• OVF (new)
• More(Nebula, CloudStack, Atl Cloud…)
• Cloud Init Modules (bunch of Python scripts)

6. Data Source
• meta-data(from cloud platform)
• Server name, IP etc
• user-data
• What you want it do do, scripts etc
• Saved to /var/lib/cloud/

7. Data Source – Metadata Service
• Metadata service as part of OpenStack
• http://169.254.169.254/latest/meta-data (user-data)
• NAT rules make this work
• Provided by nova-api or neutron-metadata-proxy

8. Data Source – Config Drive
• Like a USB stick attached to the server
• Cloud provider metadata
• User data provided via YAML and MIME encoded
files

9. Data Source – Vmware
• Similar to config drive (but more arcane?)
• cloud-init searches for a CDROM on boot
• ISO images which contain user data

10. Modules
• Add users
• Create files
• Run arbitrary commands
• Bootstrap Chef/Puppet
• More…Write your own…etc
• Configuration management? (not really)

11. Demo/Examples
https://github.com/srirajan/cloudinit-demo

12. Troubleshooting
• /var/log/cloud-init.log (verbose logs)
• /var/lib/cloud/ (data, files etc from the metadata
service or config drive
• cloudinit [h] [version] [file FILES] [debug] [-
force] {query,init,modules,single}

13. Links etc…
• https://cloudinit.readthedocs.org
• https://github.com/cloudbase/cloudbase-init

14. THANK YOU