[systemd-devel] systemd-notify --ready is not reliable
zbyszek at in.waw.pl
Thu Apr 24 14:51:42 PDT 2014
On Wed, Apr 23, 2014 at 08:50:34PM +0200, Lennart Poettering wrote:
> On Wed, 23.04.14 15:15, Eelco Dolstra (eelco.dolstra at logicblox.com) wrote:
> > Hi all,
> > I've noticed that the command "systemd-notify --ready" does not work reliably to
> > signal that a service is ready. It works sometimes, but most of the time you get
> > a message like:
> > systemd: Cannot find unit for notify message of PID 3137.
> > in the journal, and the service stays in the "activating" state.
> > The reason is that systemd-notify sends its message asynchronously and exits
> > immediately. So by the time systemd processes the message, systemd-notify has
> > probably already exited, and so systemd cannot gets cgroup. (Note that this
> > affects other systemd-notify messages as well, but for --ready it's particularly
> > bad because it causes services to "hang" in the "activating" state.)
> > Any suggestions what to do about this? I can see a few solutions:
> There is ongoing work to fix the kernel to add SCM_CGROUPS for us to
> messages. With that in place we have a race-free way to get this data
> for incoming messages. I have some hopes that this will soonishly enter
> the kernel, but then again, this story has been cookie for the past 5
> years to no successs...
What about simply waiting in the background for 10s? An ugly workaround,
but should fix the issue until we have something better.
More information about the systemd-devel