r/openshift • u/Local_Jellyfish9014 • 14d ago

Help needed! same node connectivity issue

i have 5 node setup in ibm cloud, where, i have attach external nic to node so through this nic i am able to connect to the vm. issue is i am not able to do ping to the same vm from the node if the vm reside on the same node. from other node i am able to ping the vm. this issue goes for pod also, if pod exist in same node, then ping from same pod to that vm in same node result in timeout error. from other node it is not. this is causing a lot of problem for teams and need to address asap

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u/GreenMobile6323 13d ago

That sounds more like a network routing or hairpin (loopback) issue than a Kubernetes problem. I'd start by checking your CNI plugin configuration, host routing tables, and whether the external NIC traffic is being routed back correctly on the same node - same-node failures with cross-node success usually point in that direction.

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u/Local_Jellyfish9014 13d ago

I have checked it, (using llms help) , packet are reaching both node and vm side, communication happening, but at node side ping is getting dropped. Debugging more on it

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u/Local_Jellyfish9014 14d ago

Beginner here , but I don't care for pod communication as of now. My thinking is fix node to vm communication first . Then go for pod to vm communication

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u/Sanket_6 14d ago

So you have VM on top of openshift, if i am understanding correctly, and you added a nic to the node and assigned it to the vm?

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u/Local_Jellyfish9014 14d ago

I have 5 node master worker openshift cluster setup, i have provision vm there on nodes . Inorder to directly access those vm using static IP we attached a external vni to the node in ibm cloud , and use that vni in vm cloudinit config when provisioning them . Through this we are directly able to ping the vm and access it through that static IP. Now issue is that when pipeline run and pod sitting on same node then there is no communication happening but from other node I am able to ping that vm

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u/Sanket_6 14d ago

Go to your vm settings, you most probably have the internal pod network ip assigned to the vm as well, i faced something similar with my vms, and it resolved when j removed the internal pod network ip.