Remove redundant call to get/create default security group

womax/nova

In the instance_create DB API method, it ensures the (legacy) default
security group gets created for the specified project_id if it does
not already exist. If the security group does not exist, it is created
in a separate transaction.

Later in the instance_create method, it reads the default security group
back that it wrote earlier (via the same ensure default security group
code). But since it was written in a separate transaction, the current
transaction will not be able to see it and will get back 0 rows. So, it
creates a duplicate default security group record if project_id=NULL
(which it will be, if running nova-manage db online_data_migrations,
which uses an anonymous RequestContext with project_id=NULL). This
succeeds despite the unique constraint on project_id because in MySQL,
unique constraints are only enforced on non-NULL values [1].

To avoid creation of a duplicate default security group for
project_id=NULL, we can use the default security group object that was
returned from the first security_group_ensure_default call earlier in
instance_create method and remove the second, redundant call.

This also breaks out the security groups setup code from a nested
method as it was causing confusion during code review and is not being
used for any particular purpose. Inspection of the original commit
where it was added in 2012 [2] did not contain any comments about the
nested method and it appeared to either be a way to organize the code
or a way to reuse the 'models' module name as a local variable name.

Closes-Bug: #1824435

[1] https://dev.mysql.com/doc/refman/8.0/en/create-index.html#create-index-unique
[2] https://review.opendev.org/#/c/8973/2/nova/db/sqlalchemy/api.py@1339

Change-Id: Idb205ab5b16bbf96965418cd544016fa9cc92de9

This commit is contained in:

melanie witt

2019-10-11 21:08:33 +00:00

parent 7c41365f19

commit 6ea945e3b1

2 changed files with 12 additions and 19 deletions

									
										gate/post_test_hook.sh
									
		+1
		-6
	
												View File
												
				@@ -266,13 +266,8 @@ $MANAGE db online_data_migrations

				# creation of a new deleted marker instance.

				set +e

				archive_deleted_rows

				set -e

				# Verify whether online data migrations run after archiving will succeed.

				# See for more details: https://bugs.launchpad.net/nova/+bug/1824435

				$MANAGE db online_data_migrations

				rc=$?

				set -e

				if [[ $rc -ne 2 ]]; then

				    echo "Expected return code 2 from online_data_migrations until bug 1824435 is fixed"

				    exit 2

				fi