The packetdump (comment #35) of MAAS not responding to grub's request
for the mac specific grub.cfg before grub times out, and then responding
immediately to the generic-amd64 grub cfg, clearly shows a race
condition in MAAS.

MAAS's design of dynamically generating the interface specific grub
config only after it receives the tftp request for it is susceptible to
a race condition where grub times out before MAAS can respond.

That design is not the only possible design.  All the information
required for the interface specific grub.cfg is available before the
machine ever powers on, and could be made available on the rack
controllers at that time too.

Doing so would eliminate that race condition, or at least reduce the
opportunity greatly, as we see MAAS has no problems immediately
responding and serving files that it doesn't need to dynamically
generate at request time.

There is still some question around what in the environment is
contributing to MAAS not responding faster, and what MAAS is doing while
it takes 60+ seconds to respond to the request, but that doesn't change
the fact that the current MAAS design is racy (and that's a bug).

Whatever we change in the environment to reduce the likelihood of
hitting this issue there doesn't solve the underlying race condition in
MAAS, and leaves open the possibility of hitting the issue other places
too.

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1743249

Title:
  Failed Deployment after timeout trying to retrieve grub cfg

To manage notifications about this bug go to:
https://bugs.launchpad.net/maas/+bug/1743249/+subscriptions

-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to