Weave: /proc/sys/net/bridge/bridge-nf-call-iptables not found

[cwhenderson20]

Hello all. I'll do my best to describe this problem, but I don't know much about Weave and am relatively new to Kubernetes in general.

I am using Weave with Kubernetes 1.5.2 (set up via kops) on Debian (AWS). The weave image is weaveworks/weave-kube:1.8.2.

I'm experiencing an issue where one of my Weave pods will not properly start and gets stuck in a CrashLookBackoff. I am using the private topology feature of kops, so all of my main nodes and masters are in private subnets. I have also added a public subnetted instance group whose purpose is to serve as ingress nodes to route traffic to the private nodes via nginx ingress controllers.

On all of the private nodes, Weave works as expected. However, on the public node, the Weave pod crashes constantly. The only item in the log for the weave container of the Weave pod is this:

/proc/sys/net/bridge/bridge-nf-call-iptables not found

I'm not sure what other detail to include, so if there anything specific that would help debug this, please let me know and I will provide as much as possible.

[brb]

@cwhenderson20 The newest Weave Net release (1.9.0) made /proc/sys/net/bridge/bridge-nf-call-iptables optional (see https://github.com/weaveworks/weave/issues/2581), so upgrading Weave should fix your problem.

Any idea why /proc/sys/net/bridge/bridge-nf-call-iptables is not available on your public instance?

[cwhenderson20]

@brb I'm using kops to set up Kubernetes, so upgrading weave isn't trivial. Fortunately, destroying and recreating the node seemed to fix the issue, but I have no clue as to why. Feel free to close this issue if you don't believe it warrants further investigation.

Thanks!

[brb]

Thanks for letting us know.

[brb]

@chrislovecnm Any idea why /proc/sys/net/bridge/bridge-nf-call-iptables is not available?

[chrislovecnm]

Have not seen this behavior. How is that bridge components created?

What OS is being used?

[cwhenderson20]

@chrislovecnm kops set it up automatically when I chose weave as the cni plugin. It's also using the standard kops OS, so Debian Jessie I believe.

[chrislovecnm]

@brb is that a kernel option that was missed?

[bboreham]

@chrislovecnm we are aware of one scenario where this file (sysctl) is not present; it is described in #2726. But there could be another reason, hence https://github.com/weaveworks/weave/issues/2789#issuecomment-280615549

[brb]

@chrislovecnm /proc/sys/net/bridge/bridge-nf-call-iptables is exported by the br_netfilter kernel module.

I am closing this issue. If you find more information / evidence, please re-open the issue. Thanks.

[xingjinglu]

br_netfilter

@brb Your advice worked. Thanks.

modprobe br_netfilter