In this tutorial, we will create our first cloud-init user data script and deploy it into an LXD container. We’ll be using LXD for this tutorial because it provides first class support for cloud-init user data as well as systemd support. Because it is container based, it allows for quick testing and iterating on our user data definition.
Skip this section if you already have LXD setup.
$ sudo snap install lxd
If you don’t have snap, you can install LXD using one of the other installation options.
$ lxd init --minimal
The minimal configuration should work fine for our purposes. It can always be changed at a later time if needed.
Define our user data#
Now that LXD is setup, we can define our user data. Create the
following file on your local filesystem at
#cloud-config runcmd: - echo 'Hello, World!' > /var/tmp/hello-world.txt
Launch a container with our user data#
Now that we have LXD setup and our user data defined, we can launch an instance with our user data:
$ lxc launch ubuntu:focal my-test --config=user.user-data="$(cat /tmp/my-user-data)"
Verify that cloud-init ran successfully#
After launching the container, we should be able to connect to our instance using
$ lxc shell my-test
You should now be in a shell inside the LXD instance. Before validating the user data, let’s wait for cloud-init to complete successfully:
$ cloud-init status --wait ..... cloud-init status: done $
We can now verify that cloud-init received the expected user data:
$ cloud-init query userdata #cloud-config runcmd: - echo 'Hello, World!' > /var/tmp/hello-world.txt
We can also assert the user data we provided is a valid cloud-config:
$ cloud-init schema --system --annotate Valid cloud-config: system userdata $
Finally, verify that our user data was applied successfully:
$ cat /var/tmp/hello-world.txt Hello, World! $
We can see that cloud-init has consumed our user data successfully!
Exit the container shell (i.e., using
exit or ctrl-d). Once we have
exited the container, we can stop the container using:
$ lxc stop my-test
and we can remove the container using:
$ lxc rm my-test
You can also head over to the examples page for examples of more common use cases.