Set concurrency of scenario tests to 3
In order to reduce the host load during the CI jobs execution,
the tempest concurrency for scenario jobs is reduced to 3 (from 4).
This should lighten the server load and reduce the occurrence of
random failures.
Closes-Bug: #1904858
Change-Id: I19ccb492506660dd7da56b48fe3ac9d0bc427f9d
diff --git a/zuul.d/base.yaml b/zuul.d/base.yaml
index 8644b41..cc1479b 100644
--- a/zuul.d/base.yaml
+++ b/zuul.d/base.yaml
@@ -116,3 +116,4 @@
ADVANCED_INSTANCE_TYPE: ds512M
ADVANCED_INSTANCE_USER: ubuntu
BUILD_TIMEOUT: 784
+ tempest_concurrency: 3 # out of 4