[Bug 806761] Re: Feature Request: Upstart scripts for nslcd

[Caleb Callaway]

The odd behavior turned out to be a race condition between the nslcd and
nslcd-k5start scripts: per the Upstart docs
(http://upstart.ubuntu.com/cookbook/#expect), Upstart assumes the job
has started after the first PID that is generated in the script, unless
an expect stanza is present. So, Upstart believes the nslcd-k5start job
has started as soon as the calls to sed/hostname/etc are made and starts
the nslcd job, which fails because it can't find the credentials cache
it needs.

I can think of three options, none of which look good:

1) Use kinit in a pre-start script for the nslcd-k5start job, and duplicate the K5START_START logic in both the pre-start script and the main script. 
2) Re-solve the problem that Upstart's supposed to solve with a signalling system, like letting the nslcd job wait until the nslcd-k5start job had set a flag (or a timeout occurs). Something like a spin lock.
3) Stall the nslcd script for set period of time and hope the nslcd-k5start script doesn't take very long to start.

At the moment, option 3 seems like the best of the bad options:
introducing an extra dependency and duplicating control logic seems like
a good way to introduce bugs, and implementing a lock system is robust
but complicated. A revised debdiff that uses the third option is
attached. I'm quite open to arguments in favor of another option, and
I'd be delighted to know of a non-hackish solution.

** Patch added: "Revised Upstart scripts"
   https://bugs.launchpad.net/ubuntu/+source/nss-pam-ldapd/+bug/806761/+attachment/3220650/+files/nslcd-upstart.debdiff

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https://bugs.launchpad.net/bugs/806761

Title:
  Feature Request: Upstart scripts for nslcd

Status in “nss-pam-ldapd” package in Ubuntu:
  Confirmed

Bug description:
  This forum thread contains Upstart scripts that makes nslcd (and by
  extension the whole nss-pam-ldapd package) more resilient in the face
  of network connectivity outages:
  http://ubuntuforums.org/showthread.php?t=1335022

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