Practice Test - Troubleshoot Network solution contains wrong cm name

Kubernetes
#1

Hello,

The solution to the exercise is wrong. See the cm name in the solution and the real cm in the lab

image
image2059×750 76.3 KB

#2

No, the solution is actually correct. Take a look at the volumes block for a kube-proxy pod; the cm is mounted to /var/lib/kube-proxy. If you look at the contents of the cm, you’ll see that it encodes two separate files, which the fixed ds.kube-proxy needs to reference. The solution has you change the config from /var/lib/configuration.conf to /var/lib/config.conf, which fixes kube-proxy. The reference you show in the right side of your image is the correct reference of config.conf to the kubeconfig file that kube-proxy also needs to operate. That kubeconfig file is also embedded in the cm. So this is all fine.

#3

How do I get that info, i.e. how do I know that the real path and file is /var/lib/config.conf

#4

From the YAML of ds.kube-proxy, you can tell that the cm is mounted into the pod as /var/lib/kube-proxy. You look at the CM, and see that the cm encodes two separate files, config.conf, and kubeconfig.conf. The latter of these is clearly a kubeconfig file (you can see this by looking at the text of it). So the only possible valid path for the config file is /var/lib/kube-proxy/config.conf; the path /var/lib/kube-proxy/configuration.conf must be wrong.

#5

Hello @rob_kodekloud
sorry, I still do not get where to get /var/lib/config.conf from

Config map for kube-proxy:

2
2838×450 39.6 KB

2.2
2.2814×465 31.2 KB

Daemon et volumes:

2.3
2.3576×979 76.5 KB

Thanks

#6

Look at the mounts for a kube-proxy pod. Here’s what a kube-proxy pod looks like on my minikube install:

$ minikube ssh
                         _             _
            _         _ ( )           ( )
  ___ ___  (_)  ___  (_)| |/')  _   _ | |_      __
/' _ ` _ `\| |/' _ `\| || , <  ( ) ( )| '_`\  /'__`\
| ( ) ( ) || || ( ) || || |\`\ | (_) || |_) )(  ___/
(_) (_) (_)(_)(_) (_)(_)(_) (_)`\___/'(_,__/'`\____)

$ sudo -i
# ps -aef | grep kube-proxy
root        1918    1889  0 Dec12 ?        00:01:05 /usr/local/bin/kube-proxy --config=/var/lib/kube-proxy/config.conf --hostname-override=minikube
root     1955734 1955671  0 18:52 pts/0    00:00:00 grep kube-proxy
# ls /proc/1918/root/var/lib/kube-proxy/
config.conf  kubeconfig.conf

The problem in the question is that you start out with passing the kube-proxy binary `–config=/var/lib/kube-proxy/configuration.conf; under the mounts created for that pod (which mount /var/lib/kube-proxy into the configmap kube-proxy), there is no such file as /var/lib/kube-proxy/configuration.conf. Which is why kube-proxy is in a crash state. We see from your graphic that the config.conf file in the cm is in fact a config YAML for kube-proxy, so we use that instead.