Docker integration - AttributeError: 'NoneType' object has no attribute 'endswith'

[LotharSee]

On a Debian Wheezy with a kernel 3.14 from backports:

Traceback (most recent call last):
  File "/opt/datadog-agent/agent/checks/__init__.py", line 501, in run
    self.check(copy.deepcopy(instance))
  File "/opt/datadog-agent/agent/checks.d/docker.py", line 192, in check
    stat_file = os.path.join(mountpoint, metric["file"] % (self.path_prefix, container["Id"]))
  File "/opt/datadog-agent/agent/checks.d/docker.py", line 129, in path_prefix
    stat_file_lxc = os.path.join(mountpoint, "lxc")
  File "/opt/datadog-agent/embedded/lib/python2.7/posixpath.py", line 77, in join
    elif path == '' or path.endswith('/'):
AttributeError: 'NoneType' object has no attribute 'endswith'

Then the Docker integration doesn't work.

[LotharSee]

This may happen if some cgroups are missing.

In the case, is is because of the Debian kernel. memory cgroup are built in the kernel but are disabled by default.
More details here: https://wiki.debian.org/LXC

As explained in the Debian Wiki, the solution is to enable it on grub.
Edit /etc/default/grub to add:

GRUB_CMDLINE_LINUX="cgroup_enable=memory

Then run update-grub2.
Reboot.

Now memory cgroup should be mounted with other cgroups!

[remh]

@LotharSee could you catch that error so it would give users a better information message ?
A link to this page would be great!

[remh]

Fixed with Agent 5.0.0