Bug 1843695

Summary: [OVN] Pods can not receive multicast from other pods which are in the same namespace but different node
Product: OpenShift Container Platform Reporter: Weibin Liang <weliang>
Component: NetworkingAssignee: Dumitru Ceara <dceara>
Networking sub component: ovn-kubernetes QA Contact: Weibin Liang <weliang>
Status: CLOSED ERRATA Docs Contact:
Severity: high    
Priority: medium CC: anbhat, dcbw, dceara, jboxman, mfuruta
Version: 4.5   
Target Milestone: ---   
Target Release: 4.6.0   
Hardware: Unspecified   
OS: Unspecified   
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Clone Of:
: 1866820 (view as bug list) Environment:
Last Closed: 2020-10-27 16:04:47 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 1866820    
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Description Weibin Liang 2020-06-03 20:57:48 UTC 
Description of problem:
Pods can not receive multicast from other pods which are in the same namespace but different node.

Same testing will pass in SDN cluster.

Version-Release number of selected component (if applicable):
4.5.0-0.nightly-2020-06-03-105031

How reproducible:
Always

Steps to Reproduce:
1.oc new-project  multicast-test
2.oc annotate namespace multicast-test k8s.ovn.org/multicast-enabled="true"
3.oc create -f https://raw.githubusercontent.com/weliang1/Openshift_Networking/master/Features/Pod/multicast-pod.yaml
4.Run below cmd in the two pods which are int the different nodes:
omping -m 239.255.254.24 $pod1IP $pod2IP
Actual results:

Expected results:
Both pods can join multicast group 239.255.254.24 and receive muticast traffic

Additional info:
#From SDN cluster
sh-4.2# tcpdump -nvvvv -i ens3  -een  | grep 239.255.254.24
tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes
    10.131.0.26.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
    10.131.0.26.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
    10.131.0.26.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
    10.131.0.26.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
    10.131.0.26.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
    10.129.2.22.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
sh-4.2# tcpdump -nvvvv -i vxlan_sys_4789  -een  | grep 239.255.254.24
tcpdump: listening on vxlan_sys_4789, link-type EN10MB (Ethernet), capture size 262144 bytes
    10.131.0.26.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
    10.131.0.26.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
    10.131.0.26.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
    10.131.0.26.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
    10.131.0.26.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69
    10.129.2.22.4321 > 239.255.254.24.4321: [udp sum ok] UDP, length 69

# From OVN cluster:
sh-4.2# tcpdump -nvvvv -i ens3 -een  | grep 239.255.254.24
tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes
^C1090 packets captured
1123 packets received by filter
0 packets dropped by kernel

sh-4.2# tcpdump -nvvvv -i genev_sys_6081 -een  | grep 239.255.254.24
tcpdump: listening on genev_sys_6081, link-type EN10MB (Ethernet), capture size 262144 bytes
^C118 packets captured
124 packets received by filter
0 packets dropped by kernel
Comment 4 Weibin Liang 2020-08-05 18:48:11 UTC 
Hi Aniket,

Tested in 4.6.0-0.nightly-2020-08-05-082458:
multicast not work at all


Reproduce this bug in 4.5.0-0.nightly-2020-08-03-123303:
Multicast works between the pods in the same node.
Multicast not work between the pods in the different nodes.
Comment 5 Aniket Bhat 2020-08-06 15:57:31 UTC 
@Dumitru has a fix for this. We need to pull that and point ovn-kubernetes to the build that has the patch.
Comment 12 Weibin Liang 2020-09-14 19:09:07 UTC 
Tested and verified in 4.6.0-0.nightly-2020-09-12-230035
Comment 14 errata-xmlrpc 2020-10-27 16:04:47 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (OpenShift Container Platform 4.6 GA Images), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:4196