'conntrack - DNAT load balancing' test fails from time to time
because not all the group buckets are getting hit.
In short, the test creates a group with 3 buckets with the same
weight. It creates 12 TCP sessions and expects that each bucket
will be used at least once. However, there is a solid chance that
this will not happen. The probability of having at least one
empty bucket is:
C(3, 1) x (2/3)^N - C(3, 2) x (1/3)^N
Where N is the number of distinct TCP sessions. For N=12, the
probability is about 0.023, i.e. there is a 2.3% chance for a
test to fail, which is not great for CI.
Increasing the number of sessions to 50 to reduce the probability
of failure down to 4.7e-9. In my testing, the configuration with
50 TCP sessions didn't fail after 6000 runs. Should be good
enough for CI systems.
Fixes: 2c66ebe47a88 ("ofp-actions: Allow conntrack action in group buckets.")
Signed-off-by: Ilya Maximets <[email protected]>
---
tests/system-traffic.at | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tests/system-traffic.at b/tests/system-traffic.at
index 95383275a..4a7fa49fc 100644
--- a/tests/system-traffic.at
+++ b/tests/system-traffic.at
@@ -6471,7 +6471,7 @@ on_exit 'ovs-appctl revalidator/purge'
on_exit 'ovs-appctl dpif/dump-flows br0'
dnl Should work with the virtual IP address through NAT
-for i in 1 2 3 4 5 6 7 8 9 10 11 12; do
+for i in $(seq 1 50); do
echo Request $i
NS_CHECK_EXEC([at_ns1], [wget 10.1.1.64 -t 5 -T 1 --retry-connrefused -v
-o wget$i.log])
done
--
2.34.1
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