Adds generic retries for build failures.

Add a generic scheduler retry for build failures.  Failed
build requests get casted back to scheduler for retry until
success or the maximum number of attempts is reached. The
number of attempts to make is configurable or can be
simply set to 1 to disable retries altogether.

Partially implements blueprint: scheduler-resource-race

DocImpact:

Adds a new capability to filter scheduler to enable retries of
scheduling requests.

1) New flag: scheduler_max_attempts (int) - Number of attempts to make
to schedule an instance before giving up and settting the instance to
error.
2) New RetryFilter.  Avoids re-scheduling to the same host multiple
times. (nova.scheduler.filters.RetryFilter)

Change-Id: I1127caeed4418c75372a42ca7fafacb4f061ffe3

0 files changed, 0 insertions, 0 deletions