Kube-faq

# Debugging networking on OKD4 / OpenShift 4

It's not so easy to debug network problems in OKD / OpenShift.

For a cluster-admin this method works.

**DANGER**: you have to know what your doing  

**DANGER**: you have to know network protocols and PCAP / Wireshark

## Install krew (Plugin Manager for kubectl & oc)

Krew (<https://krew.sig.k8s.io>) is a plugin manager for `kubectl` and `oc`

Install with <https://krew.sigs.k8s.io/docs/user-guide/setup/install/>

## Install ksniff

ksniff (<https://github.com/eldadru/ksniff>) is a plugin for kubectl which executes tcpdump in your destination pod (or a sidecar) and saves it or feeds it to Wireshark.

Installation: `kubectl krew install sniff` and you're done ;-)

If you want to analyze in realtime you have to install Wireshark (<https://www.wireshark.org>)

## Execute 

Assuming your destination pod named `dingdongpod` in namespace (project) `private-develop`

Do the following on your management or development machine (preferred is MacOS or Linux):

```shell

oc login -u myclusteradminaccount api.mycluster.my.domain

oc project private-develop

oc sniff -p dingdongpod

```

This executes a privileged pod in the namespace, fires tcpdump and pipes the output to your wireshark. And now you can debug!