Add net.ipv4.tcp_rmem and net.ipv4.tcp_wmem into safe sysctl list #125234

SataQiu · 2024-05-31T09:52:08Z

What would you like to be added?

net.ipv4.tcp_rmem and net.ipv4.tcp_wmem have been namespaced since torvalds/linux@356d183 (Linux Kernal Version >= 4.15)

It would be helpful to allow config these sysctls for each Pod(Application).

Why is this needed?

The good performance of some applications depends on these sysctls, for example https://docs.datastax.com/en/cassandra-oss/3.x/cassandra/install/installRecommendSettings.html#TCPsettings.

To handle thousands of concurrent connections used by Cassandra, DataStax recommends these settings to optimize the Linux network stack. We should config these sysctls as the following:

net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 65536 16777216

It would be helpful to be able to configure this for applications without needing to modify the kubelet args.

The text was updated successfully, but these errors were encountered:

k8s-ci-robot · 2024-05-31T09:52:17Z

This issue is currently awaiting triage.

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SataQiu · 2024-05-31T09:52:58Z

/sig node

HirazawaUi · 2024-05-31T11:36:21Z

/sig network
/cc @thockin

nikzayn · 2024-06-01T16:48:25Z

Hey @SataQiu, I would like to take this up after triage-accepted label. Thanks

/assign

…list kubernetes#125234 Signed-off-by: nikzayn <nikhilvaidyar1997@gmail.com>

mauri870 · 2024-06-01T17:55:10Z

@nikzayn I had started working on this yesterday, but I'm fine passing the ball to you. Please take a look at my changes, perhaps some of them are worth porting over to your PR. Thanks.

https://github.com/kubernetes/kubernetes/compare/master...mauri870:kubernetes:feature/sysctl-tcp-rmem-wmem?expand=1

mauri870 · 2024-06-01T17:57:49Z

Related work for net.ipv4.tcp_keepalive_time at #118846 can be used as inspiration as well.

nikzayn · 2024-06-01T18:32:57Z

Thanks a lot @mauri870 my bad I didn't know you were working. I should have to wait for someone to assign from next time. Thanks for passing the ball. Definitely, I will take a look and after a successful build pass will push the respective changes.

mauri870 · 2024-06-01T18:36:26Z

Thanks a lot @mauri870 my bad I didn't know you were working. I should have to wait for someone to assign from next time. Thanks for passing the ball. Definitely, I will take a look and after a successful build pass will push the respective changes.

No worries, it's my fault for not assigning the issue to myself earlier. I'm glad you were able to work on it.

…ernetes#125234 Signed-off-by: nikzayn <nikhilvaidyar1997@gmail.com>

nikzayn · 2024-06-01T18:53:36Z

Thanks a lot @mauri870 my bad I didn't know you were working. I should have to wait for someone to assign from next time. Thanks for passing the ball. Definitely, I will take a look and after a successful build pass will push the respective changes.

No worries, it's my fault for not assigning the issue to myself earlier. I'm glad you were able to work on it.

Thanks, I have made the changes. You can check that out. Do checkout of If I am missing anything. Thanks!!