[Bug 1686361] Re: systemd does not respect nofile ulimit when running in container

[Brian Murray]

Hello Christian, or anyone else affected,

Accepted systemd into zesty-proposed. The package will build now and be
available at https://launchpad.net/ubuntu/+source/systemd/232-21ubuntu4
in a few hours, and then in the -proposed repository.

Please help us by testing this new package.  See
https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how
to enable and use -proposed.Your feedback will aid us getting this
update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug,
mentioning the version of the package you tested, and change the tag
from verification-needed to verification-done. If it does not fix the
bug for you, please add a comment stating that, and change the tag to
verification-failed.  In either case, details of your testing will help
us make a better decision.

Further information regarding the verification process can be found at
https://wiki.ubuntu.com/QATeam/PerformingSRUVerification .  Thank you in
advance!

** Changed in: systemd (Ubuntu Zesty)
       Status: In Progress => Fix Committed

** Tags added: verification-needed

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1686361

Title:
  systemd does not respect nofile ulimit when running in container

Status in systemd package in Ubuntu:
  Fix Released
Status in systemd source package in Xenial:
  New
Status in systemd source package in Yakkety:
  New
Status in systemd source package in Zesty:
  Fix Committed
Status in systemd source package in Artful:
  Fix Released

Bug description:
  [Impact]

   * Containers cannot use maximum RLIMIT_NOFILE, because systemd sets
  an arbitrary cap.

  [Test Case]

   * Start container with high RLIMIT_NOFILE (e.g. 100 000)
   * Check that RLIMIT_NOFILE on the container is more than 65536

  [Regression Potential]

   * This is a feature / change of behaviour. Some users may be relying
  on the lower RLIMIT_NOFILE cap, but it should not have a negative
  impact on the host (as in creating too many file descriptors/denial of
  service).

  [Original Bug Report]

  When systemd currently starts in a container that has RLIMIT_NOFILE set to e.g.
  100000 systemd will lower it to 65536 since this value is hard-coded into systemd.
  I've pushed a patch to systemd upstream that will try to set
  the nofile limit to the allowed kernel maximum. If this fails, it will compute
  the minimum of the current set value (the limit that is set on the container)
  and the maximum value as soft limit and the currently set maximum value as the
  maximum value. This way it retains the limit set on the container.
  It would be great if we could backport this patch to have system adhere to
  nofile limits set for the container. This is especially important since user
  namespaces will allow you to lower the limit but not raise it back up afterwards.
  The upstream patch is appended.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1686361/+subscriptions