commit c308f860f0b063a74769007894b7e99639a29869
Author: Carlos Goncalves <cgoncalves@redhat.com>
Date:   Mon Oct 12 15:24:14 2020 +0000

    Fix pool delete race on load balancer cascade delete
    
    In what appears to be a race condition, load balancer cascade delete can
    fail while deleting numerous pools. The load balancer can still be
    deleted with one or more follow-up cascade delete API calls but this is
    suboptimal.
    
    Per local testing, the ValueError exception is harmless so we can just
    ignore it and continue the pool delete flow, with no orphan resources
    left behind resulting from the exception skip.
    
    Task: 41096
    Story: 2008249
    
    Change-Id: I9283d9804feb83a1d5a160da48da6146b19da88c
    (cherry picked from commit 332791ee2b3cf29d01d94a9bb53fda4043303fd8)

diff --git a/octavia/common/data_models.py b/octavia/common/data_models.py
index 9f35fae..0a5f39e 100644
--- a/octavia/common/data_models.py
+++ b/octavia/common/data_models.py
@@ -17,10 +17,13 @@
 import datetime
 import re
 
+from oslo_log import log as logging
 from sqlalchemy.orm import collections
 
 from octavia.common import constants
 
+LOG = logging.getLogger(__name__)
+
 
 class BaseDataModel(object):
     def to_dict(self, calling_classes=None, recurse=False, **kwargs):
@@ -339,7 +342,11 @@ class Pool(BaseDataModel):
                     break
         for pool in self.load_balancer.pools:
             if pool.id == self.id:
-                self.load_balancer.pools.remove(pool)
+                try:
+                    self.load_balancer.pools.remove(pool)
+                except ValueError:
+                    LOG.debug("Pool %s has already been removed from load "
+                              "balancer pools list.", pool.id)
                 break
         for l7policy in self.l7policies:
             if l7policy.redirect_pool_id == self.id: