How to check connectivity from NGINX ingress controllers to all backend pods

Need to check if NGINX controllers actually have network access to the backend pods to verify the overlay network is working and to check the overall cluster network configuration.

This script is designed to walk through all the ingress controllers[1] in a cluster and test that it can curl the backend pods from the NGINX pods.

Pre-requisites

• kubectl access to the cluster

Run script

curl https://raw.githubusercontent.com/rancherlabs/support-tools/master/NGINX-to-pods-check/check.sh | bash

Example output

Broken pod

bash ./check.sh -F Table
####################################################
Pod: webserver-bad-85cf9ccdf8-8v4mh
PodIP: 10.42.0.252
Port: 80
Endpoint: ingress-1d8af467b8b7c9682fda18c8d5053db7
Ingress: test-bad
Ingress Pod: nginx-ingress-controller-b2s2d
Node: a1ubphylbp01
Status: Fail!
####################################################
bash ./check.sh -F Inline
Checking Pod webserver-bad-8v4mh PodIP 10.42.0.252 on Port 80 in endpoint ingress-bad for ingress test-bad from nginx-ingress-controller-b2s2d on node a1ubphylbp01 NOK

Working pod

bash ./check.sh -F Table
####################################################
Pod: webserver-bad-85cf9ccdf8-8v4mh
PodIP: 10.42.0.252
Port: 80
Endpoint: ingress-1d8af467b8b7c9682fda18c8d5053db7
Ingress: test-bad
Ingress Pod: nginx-ingress-controller-b2s2d
Node: a1ubphylbp01
Status: Pass!
####################################################
bash ./check.sh -F Inline
Checking Pod webserver-good-65644cffd4-gbpkj PodIP 10.42.0.251 on Port 80 in endpoint ingress-good for ingress test-good from nginx-ingress-controller-b2s2d on node a1ubphylbp01 OK

Testing

The following commands will deploy two workloads and ingresses. One that is working with a web server that is responding on port 80. And the other will have the webserver disabled, so it will fail to connect.

kubectl apply -f https://raw.githubusercontent.com/rancherlabs/support-tools/master/NGINX-to-pods-check/example-deployment.yml

[1] An Ingress Controller is the load balancing pod which enforces the routing rules outlined in an `Ingress` resource