Communication among pods not working after exposing as service

Question

I have set up a kubernetes Cluster manually. The cluster is healthy. The nodes are up. The pods and services are also created and running.

I have a web pod which is a python flask application. A db-pod which is redis. Exposed redis as a service to be accessible from python. Exposed web pod as external service also. The external service is running in 31727 port.

When i access the web application through browser, it reports redis host is not accessible.

The application works well when deployed in a kubernetes cluster created using kubeadm/kops.

Answer 1

Sounds like kube-proxy or overlay networking issue at first glance. Are you sure kube-proxy is launched on nodes and you have a working overlay ? Can you ping pods directly on a pod-to-pod basis ?

Update: as your pod-to-pod connectivity is down, you need to look into your flannel configuration, and make sure it works fine, as well as make sure pods are started with flannel networking (ie. via CNI) rather than local docker0 interfaces network.