TLS handshake error from: EOF

[ritazh]

What steps did you take and what happened:
[A clear and concise description of what the bug is.]

Getting the following intermittent errors in the gatekeeper-system logs:

http: TLS handshake error from 172.16.0.3:42672: EOF

kube-apiserver logs during the same time range do not have equivalent errors.
Everything is functioning. No impact on functionality.

NOTE:
There isn't any actual functional issues related to these error messages and the policies are working as expected. Lots of other webhook projects have reported the same issue, the error is coming from the kube-apiserver when it drops the connection prematurely and retries afterwards.

Please provide feedback in the following issues:

The EOF errors seems be related to a Go bug golang/go#50984 and appear on Kubernetes 1.23 and 1.24 and later. see kubernetes/kubernetes#109022

What did you expect to happen:
No TLS error in pod logs

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

Environment:

• Gatekeeper version: v3.8.1 and v3.7.1
• Kubernetes version: (use kubectl version): 1.23.5

[ritazh]

The EOF errors seems be related to a Go bug golang/go#50984 and appear on Kubernetes 1.23 and 1.24 see kubernetes/kubernetes#109022

From the issue description, it does not seem like there are any actual functional issues related to these error messages (as the policies are working as expected). At the moment, there is nothing we can do to fix this, as the error is coming from Kubernetes core. We can continue to monitor this after the linked issue has been fixed and released as part of a future Kubernetes patch release.

[ritazh]

xref: #866 (comment)

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

[punnarpulusu]

This is not just related to on Kubernetes 1.23 and 1.24 this is happening on all kuberenetes ( AWS EKS ) version 1.21

[ritazh]

@punnarpulusu Can you share the exact error in the log and kubernetes and gatekeeper version?

[punnarpulusu]

@ritazh Here is the error log ... redacted some information for security purpose.

gatekeeper version is 3.8.1

  k logs -n gatekeeper deploy/gatekeeper-controller-manager -f
  Found 3 pods, using pod/gatekeeper-controller-manager-xxxxxxx-ldsc7
2022/09/08 01:14:32 http: TLS handshake error from x.x.x.x:49070: EOF
2022/09/08 01:46:37 http: TLS handshake error from x.x.x.x:35184: EOF
2022/09/08 02:47:46 http: TLS handshake error from x.x.x.x:39938: EOF
2022/09/08 06:47:20 http: TLS handshake error from x.x.x.x:38652: EOF
2022/09/08 12:37:59 http: TLS handshake error from x.x.x.x:49956: EOF
2022/09/08 13:16:45 http: TLS handshake error from x.x.x.x:56032: EOF
2022/09/08 13:41:48 http: TLS handshake error from x.x.x.x:56232: EOF
2022/09/08 16:38:13 http: TLS handshake error from x.x.x.x:60828: EOF
2022/09/08 19:02:34 http: TLS handshake error from x.x.x.x:36744: EOF

sorry about the delayed response.

[punnarpulusu]

@ritazh I am getting the same error on gatekeeper 3.9.0 as well

image: artifactory.dev.earnin.net/docker-remote/openpolicyagent/gatekeeper:v3.9.0

Here is the log

k logs -n gatekeeper deploy/gatekeeper-controller-manager -f
Found 3 pods, using pod/gatekeeper-controller-manager-69b88d77ff-v6fn8
2022/09/28 16:39:44 maxprocs: Updating GOMAXPROCS=5: determined from CPU quota
2022/09/28 16:40:01 http: TLS handshake error from x.x.x.x:48490: EOF

any idea on whats causing this issue and how I can get it fixed.

[meons]

Same here on GKE 1.22 + Gatekeeper 3.9.0:

kubectl -n gatekeeper logs deployment/gatekeeper-controller-manager | grep error
Found 3 pods, using pod/gatekeeper-controller-manager-888b9f574-h4vjz
2022/10/09 10:27:38 http: TLS handshake error from x.x.x.x:50782: EOF
2022/10/09 10:36:56 http: TLS handshake error from x.x.x.x:52720: EOF
2022/10/09 10:56:14 http: TLS handshake error from x.x.x.x:55364: EOF
2022/10/09 11:05:39 http: TLS handshake error from x.x.x.x:58102: EOF
2022/10/09 11:34:01 http: TLS handshake error from x.x.x.x:49868: EOF
2022/10/09 13:30:59 http: TLS handshake error from x.x.x.x:46064: EOF
2022/10/09 14:45:18 http: TLS handshake error from x.x.x.x:55056: EOF
2022/10/09 15:06:19 http: TLS handshake error from x.x.x.x:54452: EOF
2022/10/09 16:07:31 http: TLS handshake error from x.x.x.x:54824: EOF
2022/10/09 16:16:03 http: TLS handshake error from x.x.x.x:37644: EOF
2022/10/09 16:43:38 http: TLS handshake error from x.x.x.x:46590: EOF
2022/10/09 21:27:03 http: TLS handshake error from x.x.x.x:54706: EOF
2022/10/09 21:40:59 http: TLS handshake error from x.x.x.x:47458: EOF
2022/10/09 22:47:10 http: TLS handshake error from x.x.x.x:50688: EOF
2022/10/10 00:18:11 http: TLS handshake error from x.x.x.x:44814: EOF
2022/10/10 01:13:12 http: TLS handshake error from x.x.x.x:42378: EOF
2022/10/10 02:45:59 http: TLS handshake error from x.x.x.x:47150: EOF
2022/10/10 02:56:03 http: TLS handshake error from x.x.x.x:32800: EOF
2022/10/10 03:33:21 http: TLS handshake error from x.x.x.x:52332: EOF
2022/10/10 03:58:46 http: TLS handshake error from x.x.x.x:45042: EOF
2022/10/10 04:59:54 http: TLS handshake error from x.x.x.x:48482: EOF
2022/10/10 05:49:48 http: TLS handshake error from x.x.x.x:42376: EOF
2022/10/10 05:57:33 http: TLS handshake error from x.x.x.x:41712: EOF
2022/10/10 07:11:39 http: TLS handshake error from x.x.x.x:60302: EOF

Actually x.x.x.x are GKE control planes IPs.

[ZiaUrRehman-GBI]

Kubernetes version : 1.24.3-gke.2100

textPayload: "2022/10/31 11:20:06 http: TLS handshake error from x.x.x.x:41398: EOF"

[kfox1111]

seen on k8s 1.21.11
2022/11/03 19:17:10 http: TLS handshake error from 10.17.0.0:52110: EOF

not sure its affecting anything.

[tspearconquest]

Hello, I've noticed these before but not had time to do some proper investigation until now.

I found that these messages are coming from an IP belonging to the konnectivity pods in my kube-system namespace in Azure.

This pod is facilitating the control plane to cluster communications as per https://kubernetes.io/docs/tasks/extend-kubernetes/setup-konnectivity/

Digging into the kube-system namespace labels, I see that there is control-plane: true on that namespace.

I believe what's going on which is causing this, is that konnectivity-agent is looking for all namespaces where the label control-plane exists (regardless of the value) and trying to make a connection to the gatekeeper pods.

I found #1061 which covers the removal of the control-plane label, however it has only been partially implemented by removing the check from the validating webhook configuration in Gatekeeper (#758)

Is it safe to remove the control-plane: controller-manager label from the gatekeeper-system namespace currently, if we have already applied the admission.gatekeeper.sh/ignore: no-self-managing label?

In case it is safe, then we should push to have the control-plane label removed from the namespace as soon as possible, as this is really causing problems for teams with log monitoring agents like fluentd.

[ritazh]

NOTE

The EOF errors seems be related to a Go bug golang/go#50984 and appear on Kubernetes 1.23 and 1.24 see kubernetes/kubernetes#109022

From the issue description, it does not seem like there are any actual functional issues related to these error messages (as the policies are working as expected). At the moment, there is nothing we can do to fix this, as the error is coming from Kubernetes core. We can continue to monitor this after the linked issue has been fixed and released as part of a future Kubernetes patch release.

[tspearconquest]

Hi @ritazh I believe that is incorrect. These errors also come on Kubernetes 1.22 for us, and also others have noted in this issue that they happen on K8s 1.21.

This is not just related to on Kubernetes 1.23 and 1.24 this is happening on all kuberenetes ( AWS EKS ) version 1.21

comment

Furthermore, kubernetes/kubernetes#109022 clearly indicates the errors coming from 127.0.0.1.
The original post of this issue does not indicate 127.0.0.1, but rather has the IP addresses masked as x.x.x.x which leads me to believe that the OP is experiencing this from their 10.x.x.x/8 subnet, the same as myself.

[ritazh]

Thanks for the additional data @tspearconquest! If you remove the control-plane label from the gatekeeper-system namespace as you suggested, do you still see the error in the log?

[tspearconquest]

We're testing today and I will report back soon!

[Murtaza-Solangi]

We're testing today and I will report back soon!

Was the test successful?

[tspearconquest]

We're testing today and I will report back soon!

Was the test successful?

Hello, apologies as I put my update on the other issue: #1061

Hi @ritazh - It seems my suspicion was not correct, and removing the control-plane label did not help.

It's really interesting that this is only affecting Gatekeeper, as we do have other tools with MWH and VWH which do not see this problem, and the traffic causing the errors is 100% coming from the konnectivity-agent pods in kube-system

I also took a look in konnectivity configmap and deployment manifest in one of our clusters to see if I could find a log format option, but I'm afraid I couldn't find any. My main concern is that these are not coming in json format, so it causes a lot of spam for our fluentd instance to try to parse non-json log outputs as json.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

[tspearconquest]

Not stale.

[wondywang]

I also encountered these error logs, looking forward to someone to solve it.

[maxsmythe]

Gatekeeper works but this error happens periodically. May be, because of
cert rotation

I'd expect the same errors during cert rotation, though would think the cert rotation frequency is low enough (O(years)) for the error to never repeat in the standard lifecycle of a pod.

In any case, having multiple concurrent writers with one "winner" is probably the best model. This is essentially how leader election works anyway, and avoids needing to worry about any one pod becoming a SPOF or figuring out who is eligible to become a leader. There is an edge case where there is the possibility of a controller fight if there is an incompatible change. This can be mitigated by gradually introducing a change and leaning on our "upgrades are N - 1 compatible" policy.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

[part-time-githubber]

still an open issue

[resnostyle]

We're currently running version 1.25.15 of kube and running version v3.12.0 of the opa gatekeeper and still seeing this error.

[cccsss01]

Seeing this error on 1.27.1 with gatekeeper v3.11.0 not sure if this is causing issues with timeouts for leaderelection or not

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

[immae1]

Still a topic on AKS (1.27.7) with latest node images;

2024/02/01 08:28:47 http: TLS handshake error from 10.2.0.1:32914: EOF

[OrKarstoft]

Same issue with Kubernetes v1.27.9-gke.1092000.

[aimbot31]

still

[rjbrown57]

Seeing this is 1.26 as well

[ritazh]

Closing this issue as there isn't any actual functional issues related to these error messages and the policies are working as expected. Lots of other webhook projects have reported the same issue, the error is coming from the kube-apiserver when it drops the connection prematurely and retries afterwards.

[cbugneac-nex]

But it does unnecessarily pollute the logs with these errors in DataDog (in our case) creating unnecessary noise.

[sozercan]

@cbugneac-nex it would be good to provide that feedback in golang/go#50984 as this is not an issue Gatekeeper (or any Kubernetes webhooks) can address on its own.

[pythonking6]

This maybe separate, but I am seeing this in the Loadbalancer controller on kubernetes 1.29, terraformed from eks_blueprints:

2024/05/29 21:55:41 http: TLS handshake error from 10.0.119.240:46106: EOF