How can I disable cloud-init?

In systems that use systemd and have a current (17.0+) version of cloud-init, upstream documentation describes the process for disabling cloud-init with either of the following:

• touch /etc/cloud/cloud-init.disabled
• add cloud-init=disabled to the kernel command line.

For older versions of cloud-init (0.7.X) the following information might be useful.

You can disable cloud-init's modification of /etc/fstab in one of 2 ways.

a.) by providing cloud-config that overrides the default 'mounts' entries and disables them.

mounts:
 - [ephemeral0, null]
 - [swap, null]

b.) by disabling the mounts module from running. This is done by removing it from the 'cloud_config_modules' list that you'll see in /etc/cloud/cloud.cfg.

With regard to hostname, you can also control that also. If you just want to stop cloud-init from modifying /etc/hostname, then:

preserve_hostname: true

Also interesting to you might be manage_etc_hosts.

Both of these are documented in doc/examples/cloud-config.txt (and installed in /usr/share/doc/cloud-init/examples)

I'm interested in knowing how cloud-init is breaking /etc/fstab, though. Please file a bug using ubuntu-bug cloud-init from inside your instance, and describe what it is doing that you think is wrong.

On Ubuntu 20.04, these steps worked for me to disable and remove cloud-init:

Run this command to disable:

sudo touch /etc/cloud/cloud-init.disabled

Reboot machine.

Run these commands to remove:

sudo apt-get purge cloud-init
sudo rm -rf /etc/cloud/; sudo rm -rf /var/lib/cloud/