2.6 KiB
CloudInit
Cloud-init is a program "that handles the early initialization of a cloud instance"[^n]. In other words, you can, on a "cloud-init"-ready template VM, pass a lot of data at first boot:
- setting the hostname
- add ssh keys
- automatically grow the file system
- create users
- and a lot more!
This tool is pretty standard and used everywhere. A lot of existing cloud templates are using it.
So it means very easily customizing your VM when you create it from a compatible template. It brings you closer to the "instance" principle, like in Amazon cloud or OpenStack.
Requirements
You only need to use a template of a VM with CloudInit installed inside it. Check this blog post to learn how to install CloudInit.
Note: In XOA 5.31, we changed the cloud-init config drive type from OpenStack to the NoCloud type. This will allow us to pass network configuration to VMs in the future. For 99% of users, including default cloud-init installs, this change will have no effect. However if you have previously modified your cloud-init installation in a VM template to only look for openstack drive types (for instance with the datasource_list setting in /etc/cloud/cloud.cfg) you need to modify it to also look for nocloud.
Usage
First, select your compatible template (CloudInit ready) and name it:
Then, activate the config drive and insert your SSH key. Or you can also use a custom CloudInit configuration:
CloudInit configuration examples are available here.
You can extend the disk size (in this case, the template disk was 8 GiB originally). We'll extend it to 20GiB:
Finally, create the VM:
Now start the VM and SSH to its IP:
- the system has the right VM hostname (from VM name)
- you don't need to use a password to access it (thanks to your SSH key):
$ ssh centos@192.168.100.226
[centos@tmp-app1 ~]$
The default cloud-init configuration can allow you to be to be a sudoer directly:
[centos@tmp-app1 ~]$ sudo -s
[root@tmp-app1 centos]#
Check the root file system size: indeed, it was automatically increased to what you need:
[centos@tmp-app1 ~]$ df -h
/dev/xvda1 20G 1,2G 18G 6% /