Add a delay between killing teamd processes #3325
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When killing 10 or more teamd processes, add a delay of 0.1 seconds after every 10 kill signals/proceses. This is because in the LAG scale tests (in `ecmp/inner_hashing/test_inner_hashing_lag.py` in sonic-mgmt), it may create 100 LAGs, and when destroying them all, some of those LAGs may fail to be properly destroyed, leaving some stale port channels around. This seems to be because the netlink socket buffers on which the teamd processes get notifications become full with events of the other port channels/interfaces going down. As a workaround, add some delays in killing the teamd processes, so that the netlink buffers don't become full, causing messages to get dropped. This delay was randomly chosen, and it seems to work well with 100 LAGs on a KVM. It can probably made to be a bit more aggressive if needed (i.e. maybe 0.05 seconds every 20 processes). Signed-off-by: Saikrishna Arcot <[email protected]>
Signed-off-by: Saikrishna Arcot <[email protected]>
This requires overriding some libc functions and capturing information about kill signals sent or intercepting file open operations. Signe -off-by: Saikrishna Arcot <[email protected]>
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/AzurePipelines run |
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Azure Pipelines successfully started running 1 pipeline(s). |
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Comparing the time needed to send SIGTERM to the teamd processes before and after this change, it appears that the time is roughly the same for about 70 LAGs, as tested on a physical device. Before: After: In both cases, for 70 LAGs, it took about 0.6-0.7 seconds to send SIGTERM to the teamd processes, but the distribution of SIGTERMs sent is different. However, on this device, there are still some netlink messages getting dropped resulting in the cleanup not being complete. |
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@saiarcot895 Can you please run your changes with test_po_cleanup and test_po_cleanup_after_reload? We are noticing these tests statically fail with your changes |
100ms might not be enough on slow systems for the teamd shutdown sequence to actually be staggered. Signed-off-by: Saikrishna Arcot <[email protected]>
… into teamd-delay-kill
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@saiarcot895 Do we have an updated fix? |
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Updated syslog after changes: SIGTERM signal to the teamd supervisord was sent at 07:41:40, and the container exited at 07:41:46. Teamd container is also configured to have a 60-second wait time (instead of the 10-second wait time) for termination, meaning docker will wait 60 seconds for the container to go down before forcefully killing it. This means that a 6-second wait time here is fine. |
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judyjoseph
reviewed
Dec 15, 2024
Signed-off-by: Saikrishna Arcot <[email protected]>
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Azure Pipelines successfully started running 1 pipeline(s). |
prsunny
reviewed
Jan 8, 2025
cfgmgr/teammgr.cpp
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| SWSS_LOG_ERROR("Failed to read port channel %s pid: %s", alias.c_str(), e.what()); | ||
| return false; | ||
| ifstream pidfile("/var/run/teamd/" + alias + ".pid"); | ||
| if (pidfile.is_open()) { |
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@saiarcot895 , can you please move all { -> new line to be aligned with the coding style
prsunny
reviewed
Jan 8, 2025
cfgmgr/teammgr.cpp
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| pidFile >> pid; | ||
| aliasPidMap[alias] = pid; | ||
| SWSS_LOG_INFO("Read port channel %s pid %d", alias.c_str(), pid); | ||
| } else { |
Signed-off-by: Saikrishna Arcot <[email protected]>
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/azp run |
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Azure Pipelines successfully started running 1 pipeline(s). |
Signed-off-by: Saikrishna Arcot <[email protected]>
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/azp run |
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Azure Pipelines successfully started running 1 pipeline(s). |
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/azp run |
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What I did
When killing 10 or more teamd processes, add a delay of 0.1 seconds after every 10 kill signals/proceses. This is because in the LAG scale tests (in
ecmp/inner_hashing/test_inner_hashing_lag.pyin sonic-mgmt), it may create 100 LAGs, and when destroying them all, some of those LAGs may fail to be properly destroyed, leaving some stale port channels around. This seems to be because the netlink socket buffers on which the teamd processes get notifications become full with events of the other port channels/interfaces going downWhy I did it
As a workaround, add some delays in killing the teamd processes, so that the netlink buffers don't become full, causing messages to get dropped.
This delay was randomly chosen, and it seems to work well with 100 LAGs on a KVM. It can probably made to be a bit more aggressive if needed (i.e. maybe 0.05 seconds every 20 processes).
How I verified it
On a KVM testbed with t0-116 topology with a bit more than 100 LAGs, stop teamd using
sudo systemctl stop teamd, and verify that all of the LAGs were deleted, and there were no messages from the kernel similar to the following:Details if related
Partial fix for sonic-net/sonic-buildimage#19310.