Lab 3.1 POD cilium-XXXXX always with STATUS: CrashLoopBackOff (Ubuntu 22.04)

okanovic.eldin

Hi there,
I am having difficulties with the Instalation of Kubernetes on Ubuntu 22.04 LTS.
Everything went fine until step nr. 23. I was following all the previous steps and using all configuration files provided in the course tarball.

After step nr. 23:

root@ubuntu:˜# kubeadm init --config=kubeadm-config.yaml --upload-certs | tee kubeadm-init.out

the pods are looking like this:

ubuntu@ubuntu:~$ kubectl -n kube-system get pods
NAME                               READY   STATUS             RESTARTS        AGE
cilium-6d8fr                       0/1     CrashLoopBackOff   9 (4m40s ago)   26m
cilium-operator-788c7d7585-n9f26   1/1     Running            0               26m
cilium-operator-788c7d7585-rhqtx   0/1     Pending            0               26m
coredns-5d78c9869d-7sj44           0/1     Pending            0               29m
coredns-5d78c9869d-mbq28           0/1     Pending            0               29m
etcd-ubuntu                        1/1     Running            0               29m
kube-apiserver-ubuntu              1/1     Running            0               29m
kube-controller-manager-ubuntu     1/1     Running            0               29m
kube-proxy-rwgr4                   1/1     Running            0               29m
kube-scheduler-ubuntu              1/1     Running            0               29m

In description of cilium-6d8fr I am getting following event:

ubuntu@ubuntu:~$ kubectl -n kube-system describe pod cilium-6d8fr
...
Warning  Unhealthy  35m (x3 over 36m)    kubelet            Startup probe failed: Get "http://127.0.0.1:9879/healthz": dial tcp 127.0.0.1:9879: connect: connection refused
  Warning  BackOff    77s (x178 over 35m)  kubelet            Back-off restarting failed container cilium-agent in pod cilium-6d8fr_kube-system(33fd142a-b736-4a08-b8c2-4d1bc18f9f0a)

Can somebody explain or give me directions what to analyse next. Currently I am without a idea and cannot find anything usefull on the internet about this issue.

Thanks

chrispokorni

Hi @okanovic.eldin,

Ubuntu 22.04 LTS is known to interfere with the networking configuration of the Kubernetes components.
Please use the recommended OS - Ubuntu 20.04 LTS.

Regards,
-Chris

okanovic.eldin

Hi @chrispokorni

Thank you for your comment.

I forgot to mention in my question that I am testing on the Ubuntu 22.04 LTS (minimal Kernel configuration), and that was the problem all the time. It doesn't meet the Cilium Requierements for the Linux Kernel. After Analysis of cilium-pod logs I found out that most of Kernel modules for Cilium are missing.

So I had to install linux extra kernel modules with:

sudo apt-get update
sudo apt install linux-generic
sudo apt install linuc-generic-hwe-22.04

And TADA:

ubuntu@ubuntu:~$ kubectl -n kube-system get pods
NAME                               READY   STATUS    RESTARTS      AGE
cilium-operator-788c7d7585-k7lbd   0/1     Pending   0             16m
cilium-operator-788c7d7585-xdkvq   1/1     Running   0             16m
cilium-vdblt                       1/1     Running   0             16m
coredns-5d78c9869d-kdnsm           1/1     Running   0             24m
coredns-5d78c9869d-vntqd           1/1     Running   0             24m
etcd-ubuntu                        1/1     Running   1 (18m ago)   24m
kube-apiserver-ubuntu              1/1     Running   1 (18m ago)   24m
kube-controller-manager-ubuntu     1/1     Running   1 (18m ago)   24m
kube-proxy-dgkh9                   1/1     Running   1 (18m ago)   24m
kube-scheduler-ubuntu              1/1     Running   1 (18m ago)   24m

Just to avoid the confusion, I have installed kubernetes from the scratch, so the Pod-names above are different from my first post.

Regards,
Eldin