From 8f25346de2b279ecb9358e7fc38ce448daccc002 Mon Sep 17 00:00:00 2001 From: Sebastiaan van Steenis Date: Wed, 3 Apr 2019 14:38:44 +0200 Subject: [PATCH] Add note on MTU in network troubleshooting --- .../v2.x/en/troubleshooting/networking/_index.md | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/content/rancher/v2.x/en/troubleshooting/networking/_index.md b/content/rancher/v2.x/en/troubleshooting/networking/_index.md index 53e0c0737fe..75173ccd167 100644 --- a/content/rancher/v2.x/en/troubleshooting/networking/_index.md +++ b/content/rancher/v2.x/en/troubleshooting/networking/_index.md @@ -77,6 +77,16 @@ NODE1 cannot reach NODE3 Cleanup the alpine DaemonSet by running `kubectl delete ds/overlaytest`. +### Check if MTU is correctly configured on hosts and on peering/tunnel appliances/devices + +When the MTU is incorrectly configured (either on hosts running Rancher, nodes in created/imported clusters or on appliances/devices in between), error messages will be logged in Rancher and in the agents, similar to: + +* `websocket: bad handshake` +* `Failed to connect to proxy` +* `read tcp: i/o timeout` + +See [Google Cloud VPN: MTU Considerations](https://cloud.google.com/vpn/docs/concepts/mtu-considerations#gateway_mtu_vs_system_mtu) for an example how to configure MTU correctly when using Google Cloud VPN between Rancher and cluster nodes. + ### Resolved issues #### Overlay network broken when using Canal/Flannel due to missing node annotations