openstack/nova
Code Issues Proposed changes

Add more documentation for RetryFilter

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Given that we have some confusion with a NoValidHost returned by a failing
RetryFilter, adding more explanations to the devref to help the operators.

Change-Id: I1f88379a5c1bf6f87ee99dbddd04714ba8def144
This commit is contained in:
Sylvain Bauza 2015-10-08 12:22:51 +02:00
parent e58210cb2a
commit 63bef6a637
1 changed files with 10 additions and 2 deletions
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12
doc/source/filter_scheduler.rst
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@ -262,8 +262,16 @@ creation of the new server for the user. The only exception for this rule is
directly. Variable naming, such as the ``$free_ram_mb`` example above, should
be based on those attributes.
The |RetryFilter| filters hosts that have already been attempted for scheduling.
It only passes hosts that have not been previously attempted.
The |RetryFilter| filters hosts that have already been attempted for
scheduling. It only passes hosts that have not been previously attempted. If a
compute node is raising an exception when spawning an instance, then the
compute manager will reschedule it by adding the failing host to a retry
dictionary so that the RetryFilter will not accept it as a possible
destination. That means that if all of your compute nodes are failing, then the
RetryFilter will return 0 hosts and the scheduler will raise a NoValidHost
exception even if the problem is related to 1:N compute nodes. If you see that
case in the scheduler logs, then your problem is most likely related to a
compute problem and you should check the compute logs.
The |TrustedFilter| filters hosts based on their trust. Only passes hosts
that match the trust requested in the ``extra_specs`` for the flavor. The key