Lab 3.1 - kubeadm init fails with message "unable to create ConfigMap"

mgallina

I am following Lab 3.1 and I have issues with creating the kubernetes cluster.
On the kubeadm init command of point 23, I have the error that you can see in the attached log file.
As you can see, it seems the POST to create the ConfigMap fails. Bt the previous POST worked fine.
Anyone can help me to solve this issue?

Thanks,
Massimo

mgallina

I am working with VirtualBox VMs and Ubuntu 22.04

chrispokorni

Hi @mgallina,

The lab guide calls for Ubuntu 20.04 LTS. Please use the recommended version.

If the hypervisor uses 192.168.x.y IP addresses for VM nodes, please ensure your calico network plugin and the kubeadm-config.yaml file respectively are edited with an entirely different pod subnet to prevent overlapping IP addresses in the cluster.

The configmap is not created because of a timeout, as you can see in the attached log. When provisioning the local VMs, please ensure a single bridged network interface per VM with promiscuous mode set to allow all inbound traffic, with at least 2 CPU cores, 6-8 GB RAM and 15-20 GB disk space per VM.

Regards,
-Chris

mgallina

@chrispokorni with Ubuntu 20.04 everything works fine.
However I don't understand why Ubuntu 22.04 gives the issue.

chrispokorni

Hi @mgallina,

Any deviation from the recommended versions may introduce dependency issues, incompatibilities that are otherwise addressed during the installation and configuration steps. When the content of the lab exercises will migrate to another OS version, those compatibility issues should be resolved and tested as well.

Regards,
-Chris