From f63dc09206a41c85edc92117c3e9cf3a3d49b820 Mon Sep 17 00:00:00 2001
From: Slawek Kaplonski <skaplons@redhat.com>
Date: Tue, 1 Dec 2020 09:18:41 +0100
Subject: [PATCH] Limit usage of resources in the fullstack tests job

To limit usage of resources (mostly memory) in the fullstack job and
to avoid oom killer to kill e.g. mysqld service, this patch:

* Makes number of API workers changeable by tests, as a parameter to
  EnvironmentDescription and defaults its value to 1. As neutron server
  is spawned separately for each test and is used only to process just
  few API requests during that single test so this should be still
  enough there, and where more API workers are needed (like some dhcp HA
  tests: TestDhcpAgentHARaceCondition) it can be changed,
* reduces number of test run workers from 4 to 3 - job will run slower
  but hopefully more stable,
* in the functional and fullstack tests job definition disable etcd3
  service - this will not save us a lot of memory but still it's not
  needed at all so why to run it there.

Change-Id: If19803ab6db144e2d17d6805d379c1c76d8fa343
Closes-Bug: #1906366
---
 neutron/tests/fullstack/resources/config.py      | 2 +-
 neutron/tests/fullstack/resources/environment.py | 4 +++-
 neutron/tests/fullstack/test_dhcp_agent.py       | 3 +++
 tox.ini                                          | 2 +-
 zuul.d/base.yaml                                 | 1 +
 5 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/neutron/tests/fullstack/resources/config.py b/neutron/tests/fullstack/resources/config.py
index 17ba6195ea5..9d469cefe41 100644
--- a/neutron/tests/fullstack/resources/config.py
+++ b/neutron/tests/fullstack/resources/config.py
@@ -82,7 +82,7 @@ class NeutronConfigFixture(ConfigFixture):
                      'password': rabbitmq_environment.password,
                      'host': rabbitmq_environment.host,
                      'vhost': rabbitmq_environment.vhost},
-                'api_workers': '2',
+                'api_workers': str(env_desc.api_workers),
             },
             'database': {
                 'connection': connection,
diff --git a/neutron/tests/fullstack/resources/environment.py b/neutron/tests/fullstack/resources/environment.py
index a2bb2f1f961..f42ae0c5cb5 100644
--- a/neutron/tests/fullstack/resources/environment.py
+++ b/neutron/tests/fullstack/resources/environment.py
@@ -40,7 +40,8 @@ class EnvironmentDescription(object):
                  global_mtu=constants.DEFAULT_NETWORK_MTU,
                  debug_iptables=False, log=False, report_bandwidths=False,
                  has_placement=False, placement_port=None,
-                 dhcp_scheduler_class=None, ml2_extension_drivers=None):
+                 dhcp_scheduler_class=None, ml2_extension_drivers=None,
+                 api_workers=1):
         self.network_type = network_type
         self.l2_pop = l2_pop
         self.qos = qos
@@ -62,6 +63,7 @@ class EnvironmentDescription(object):
         if self.log:
             self.service_plugins += ',log'
         self.ml2_extension_drivers = ml2_extension_drivers
+        self.api_workers = api_workers
 
     @property
     def tunneling_enabled(self):
diff --git a/neutron/tests/fullstack/test_dhcp_agent.py b/neutron/tests/fullstack/test_dhcp_agent.py
index 6f0936fcbe5..a11a8ac1d59 100644
--- a/neutron/tests/fullstack/test_dhcp_agent.py
+++ b/neutron/tests/fullstack/test_dhcp_agent.py
@@ -38,6 +38,7 @@ class BaseDhcpAgentTest(base.BaseFullStackTestCase):
     ]
     boot_vm_for_test = True
     dhcp_scheduler_class = None
+    api_workers = 1
 
     def setUp(self):
         host_descriptions = [
@@ -52,6 +53,7 @@ class BaseDhcpAgentTest(base.BaseFullStackTestCase):
                 arp_responder=False,
                 agent_down_time=self.agent_down_time,
                 dhcp_scheduler_class=self.dhcp_scheduler_class,
+                api_workers=self.api_workers,
             ),
             host_descriptions)
 
@@ -205,6 +207,7 @@ class TestDhcpAgentHARaceCondition(BaseDhcpAgentTest):
     agent_down_time = 30
     number_of_hosts = 2
     boot_vm_for_test = False
+    api_workers = 2
     dhcp_scheduler_class = ('neutron.tests.fullstack.schedulers.dhcp.'
                             'AlwaysTheOtherAgentScheduler')
 
diff --git a/tox.ini b/tox.ini
index 576bd69e27a..f8f9f81e995 100644
--- a/tox.ini
+++ b/tox.ini
@@ -76,7 +76,7 @@ deps =
 commands =
   {toxinidir}/tools/generate_dhclient_script_for_fullstack.sh {envdir}
   {toxinidir}/tools/deploy_rootwrap.sh {toxinidir} {envdir}/etc {envdir}/bin
-  stestr run --concurrency 4 {posargs}
+  stestr run --concurrency 3 {posargs}
 
 [testenv:dsvm-fullstack-gate]
 setenv = {[testenv:dsvm-fullstack]setenv}
diff --git a/zuul.d/base.yaml b/zuul.d/base.yaml
index 4342d508bda..fc7c7e04ebe 100644
--- a/zuul.d/base.yaml
+++ b/zuul.d/base.yaml
@@ -24,6 +24,7 @@
       devstack_services:
         # Ignore any default set by devstack. Emit a "disable_all_services".
         base: false
+        etcd3: false
       devstack_localrc:
         INSTALL_TESTONLY_PACKAGES: true
         DATABASE_PASSWORD: stackdb