hostname module error inside LXD containers: Failed to activate service 'org.freedesktop.hostname1': timed out

[selivan]

SUMMARY

In LXD contaiers hostname module fails with error Failed to activate service 'org.freedesktop.hostname1': timed out

ISSUE TYPE

• Bug Report

COMPONENT NAME

hostname

ANSIBLE VERSION

ansible 2.6.1
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/home/user/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/dist-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.12 (default, Dec  4 2017, 14:50:18) [GCC 5.4.0 20160609]

CONFIGURATION

OS / ENVIRONMENT

LXD containers host: Ubuntu 18.04 bionic
LXD version: 3.0.1
Container: Ubuntu 16.04 xenial

STEPS TO REPRODUCE

• Launch LXD container with Ubuntu Xenial: lxc launch ubuntu:xenial mycontainer
• Configure container host it in inventory
• Run following task on it:

- name: update hostname
  hostname: name="container1"

EXPECTED RESULTS

Hostname should be updated

ACTUAL RESULTS

container1 | FAILED! => {
    "changed": false, 
    "invocation": {
        "module_args": {
            "name": "container1"
        }
    }, 
    "msg": "Command failed rc=1, out=, err=Could not get property: Failed to activate service 'org.freedesktop.hostname1': timed out\n"
}

hostname shell command inside container works fine, container's hostname is updated. So it's ansible module problem.

[ansibot]

Files identified in the description:

• lib/ansible/modules/system/hostname.py

If these files are inaccurate, please update the component name section of the description or use the !component bot command.

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[ansibot]

cc @alikins @saito-hideki
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[jjo]

This seems to come from:

• https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1789627
• https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1780227
  , the fix requiring some pretty recent Ubuntu kernel releases.

IMO under lxc we should fallback to non systemd hostname control
methods.

[ansibot]

Files identified in the description:

• lib/ansible/modules/hostname.py

If these files are incorrect, please update the component name section of the description or use the !component bot command.

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[relrod]

After discussing this in a backlog, we aren't sure there's much we can do to address this. We can't immediately fall back to not using systemd because there are cases where a container can use systemd and we would break those cases.

If you really need this, you can use a command task (assuming the container allows you to set the hostname) instead of using the hostname module.

[selivan]

@relrod You can fall back after failing to use systemd. Something like:

1. check that systemd is available at all, lot of container enviroments don't have it
2. if 1 is true, try to set hostname with systemd
3. if 1 is false or 2 failed - set it without systemd

After I committed this issue I of course used workaround. But I still think it's a good idea to fix this, rather than continue having an obvious bug.