Wednesday, July 29, 2020

Tip: No route to host issues in Kubernetes Pods


    We see intermittent the network issues in OKE (Oracle Kubernetes Engine). ingress controller pods have difficult to access other services.  We use curl to test the network port, we get an error like below:
$ curl -v telnet://
* Expire in 0 ms for 6 (transfer 0x560b9cdd7dd0)
*   Trying
* Expire in 200 ms for 4 (transfer 0x560b9cdd7dd0)
* connect to port 9090 failed: No route to host


   There are quite a few reasons for that. Check my another blog 
   In this case, it is related to firewall ports open. 
  By default, the network team open all ingress and egress ports for the same worker nodes Subnet which means no firewall among all worker nodes.  However, it was set stateful.  As Kubernetes overly network heavily depends on UDP which is stateless, so we need to open ports as stateless

No comments: