Ubuntu – How to disable cloud-init


I have a fully-configured instance and an image from that for an autoscaling group. When autoscaling new instances from this image, it calls cloud-init. cloud-init changes the hostname and breaks fstab.

I want to prevent cloud-init from starting on instance launch.

Best Answer

  • 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.

     - [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.

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