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Setup kubernetes for GNU/Linux

This section apply only to configure kubernetes for GNU/Linux.

abcdesktop.io support docker mode and kubernetes mode. In this section we will study how abcdesktop.io is working in kubernetes mode. The abcdesktop.io kubernetes mode is recommended for enterprise use, all user containers can be distributed on different hosts.

Requirements

Linux Requierements

Installation

The following commands will let you prepare kubernetes on one node. In this case, all applications run on a single node. It's recommended to start with a single node.

Kubernetes Master Node

Step 1: Disable swap memory (if running)

You need to disable swap memory on nodes as Kubernetes does not perform properly on a system that is using swap memory. Run the following command in order to disable swap memory. 

swapoff -a

If you have some swaps in /etc/fstab, just comment them out. swapoff -a will disable all swaps temporarily.

  • disable by masking it with sysctl:
systemctl mask dev-zram1.swap
Created symlink /etc/systemd/system/dev-zram1.swap → /dev/null.

Step 2: init kubernetes

Run the following command as sudo on the master node:

kubeadm init --pod-network-cidr=10.244.0.0/16

The process might take a minute or more depending on your internet connection.

To be able to manage your kubernetes server, you need to run the following commands as a regular user:

mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

Step 3: Permit Schedule

Taints are Kubernetes flags to prevent Pod Scheduling. Remove the taints on the master so that you can schedule pods on it.

kubectl taint node `hostname` node-role.kubernetes.io/control-plane:NoSchedule-

It should return the following string.

node/<your-hostname> untainted

Taints are Kubernetes flags to prevent Pod Scheduling.

Confirm that you now have a node in your cluster with the following command.

kubectl get nodes -o wide

It should return something like the following.

NAME      STATUS     ROLES           AGE     VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION      CONTAINER-RUNTIME
hostname  NotReady   control-plane   3m17s   v1.25.3   192.168.7.187   <none>        Ubuntu 22.04.1 LTS   5.15.0-52-generic   containerd://1.6.9

Step 4: Deploy flannel through the master node

A pod network is a medium of communication between the nodes of a network. We are deploying flannel network on our cluster through the following command:

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

It should return the following strings.

namespace/kube-flannel created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created
Check node status

Now when you see the status of the nodes, you will see that the master-node is ready :

kubectl get nodes -o wide

NAME      STATUS   ROLES           AGE     VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION      CONTAINER-RUNTIME
Hostname  Ready    control-plane   4m12s   v1.25.3   192.168.7.187   <none>        Ubuntu 22.04.1 LTS   5.15.0-52-generic   containerd://1.6.9

At this step, there is no more Taints and your node is Ready.

Next step, continue with the setup abcdesktop for kubernetes.