kubernetes

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Setup Non HA Kubernetes using K3S

Feb 25, 2025

Adekabang

Tukang Ngoprek

Last Update: 25 February 2025

K3S

Resources

• Quick Start K3S
• K3S: Setup dan Konfigurasi Kubernetes Cluster
• MetalLB: Installation with Helm
• Helm: Installing from APT - Ubuntu/Debian

Non-HA Control Plan Setup and Configuration

The implementation Scenario will be configured:

• 1 Master Node
• 2 Worker Node

These three nodes will be deployed in Proxmox VE, with each specification of node:

• 4 vCPU
• 16 GB of memory
• 50 GB of storage
• Ubuntu 20.04

Step by step

VM Setup

1. Update and upgrade the package repository to the newest version.

   sudo apt update -y
   sudo apt upgrade -y

2. (optional) rename and set /etc/host for each node became:

   1. Master node → kube-master-1
   2. Worker node → kube-worker-1, kube-worker-2

   #edit /etc/hosts and add this at the end of file (adjust ip address)
   10.0.2.200 kube-master-1
   10.0.2.199 kube-worker-1
   10.0.2.198 kube-worker-2

3. Reboot to finalize the upgrade and apply the hostname.

4. Install docker with this script (Docker: Install using the conveniencescript)

   curl -fsSL https://get.docker.com -o get-docker.sh
   sudo sh get-docker.sh

5. Check docker command and version

   docker ps
   docker version

   

Master Node Setup

1. Defined the K3s token. Save this token and make sure this token is the same for all nodes

   export K3S_TOKEN=kubernetesdemo123

2. The installation of master node, using this script:

   1. install the server as master node
   2. disable Traefik for ingress → will use Nginx ingress
   3. disable Servicelb → will use MetalLB
   4. disable local-storage → will use Ceph CSI
   5. declare to use docker

   curl -sfL https://get.k3s.io | sh -s - server --disable traefik --disable servicelb --disable local-storage --docker

   

3. Check the service status, make sure it is active

   systemctl status k3s.service

   

4. Check kubectl command. It will display 1 node only (which is the master node).

   kubectl get node

   

   ⚠️ if the get error unable to read /etc/rancher/k3s/k3s.yml , you can fix with this step.

   mkdir .kube
   sudo cp /etc/rancher/k3s/k3s.yaml .kube/config.yaml
   sudo chown $USER:$GROUP .kube/config.yaml
   export KUBECONFIG=~/.kube/config.yaml

   or if you have not start the installation, you can add --write-config 644 in the end of the script, like this:

   curl -sfL https://get.k3s.io | sh -s - server --disable traefik --disable servicelb --disable local-storage --docker --write-config 644

Worker Node Setup

Do this step for all the worker node, in this scenario will be kube-worker-1 and kube-worker-2.

1. Defined the K3s token. Use the same token as defined in master node.

   export K3S_TOKEN=kubernetesdemo123

   ⚠️ If you forget the token on the master node, you can check and on the master node on this file. Copy all the string.

   cat /var/lib/rancher/k3s/server/node-token

2. The installation of worker nodes, using this script:

   1. install the server as worker node (agent)
   2. declare to use docker
   3. define the server endpoint to master node ip or domain

   curl -sfL https://get.k3s.io | sh -s - agent --docker --server https://kube-master-1:6443

3. Check the service in the worker nodes

   systemctl status k3s-agent.service

   

4. Check kubectl command in master node. Now, it will display more than 1 node (which is the includes all the installed worker nodes).

   kubectl get node

   

⚠️ If you stuck in when starting k3s-agent. Make sure worker node and master node can be connecting. it could be firewall, proxy server, or incorrect/mismatched MTU. Script below can be use for check the connectivity.

curl -ks https://ipaddress:6443/ping

Install and Configure services in the Master Node

Because we disable some service in the master node. Now we are going to install it the replacement services.

HELM - Package Manager Installation

1. Install Helm using script below (the latest script can be seen on the Helm docs):

   curl https://baltocdn.com/helm/signing.asc | gpg --dearmor | sudo tee /usr/share/keyrings/helm.gpg > /dev/null
   sudo apt-get install apt-transport-https --yes
   echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/helm.gpg] https://baltocdn.com/helm/stable/debian/ all main" | sudo tee /etc/apt/sources.list.d/helm-stable-debian.list
   sudo apt-get update
   sudo apt-get install helm

2. Check the version

   helm version

   

MetalLB - Load Balancer Installation and Configuration

Services

• As default, all resources in Kubernetes are isolated, specifically pods.
• Pods are isolated by default. To enable communication between pods or with the external network, you need to configure Services.
• There are several type of service:
  • ClusterIP → Default services, ClusterIP services provide an internal IP address within the cluster that other pods can use to communicate. They are not directly accessible from outside the cluster.
  • NodePort (Port 30000-32767) → NodePort services expose a port on each node in the cluster, allowing external access. The port range 30000-32767 is the default range.
  • LoadBalancer → LoadBalancer services provision an external load balancer that distributes traffic to multiple pods.

Installation Step by Step

1. Add metallb repository to helm

   helm repo add metallb https://metallb.github.io/metallb

2. Check the repo list

   helm repo ls

3. Search the metallb

   helm search repo metallb

   

4. Pull the metallb from the repository, it will download tgz file.

   # run this in the home dir or other directory
   helm pull metallb/metallb
   # extract the tgz
   tar xvf metallb-*

5. Change directory to metallb and if there any configuration changes, you can edit values.yaml

   cd metallb
   
   #optional
   vim values.yaml

6. Install metallb using helm

   • Set the chart name to metallb
   • Define the file to values.yaml
   • Put the namespace to metallb-system
   • Enable debug mode
   • Create metallb-system namespace

   helm install metallb -f values.yaml . -n metallb-system --debug --create-namespace

7. Check the status, if the status still init, wait until running.

   kubectl -n metallb-system get all
   kubectl -n metallb-system get pod -w

   

Configuration

1. First, define the address pool on ipaddresspool.yaml

   apiVersion: metallb.io/v1beta1
   kind: IPAddressPool
   metadata:
     name: default-pool
     namespace: metallb-system
   spec:
     addresses:
     - 10.0.2.11-10.0.2.100 #adjust this range

2. Apply the configuration

   kubectl apply -f ipaddresspool.yaml

   

3. Then, we define the L2 Advertisement config on l2advertisement.yaml

   apiVersion: metallb.io/v1beta1
   kind: L2Advertisement
   metadata:
     name: default
     namespace: metallb-system
   spec:
     ipAddressPools:
     - default-pool

4. Apply the configuration

   kubectl apply -f l2advertisement.yaml

   

Test the Load Balancer

1. Run demo app for the testing, the demo app using nginx image.

   kubectl run app-demo-1 --image=nginx --port=80
   
   #check the pod status, wait until running
   kubectl get pod

2. Since by default pod cannot communicate to outside, we need to create the service to expose the pods.

   kubectl expose pod app-demo-1 --type=LoadBalancer --target-port=80 --port=80 --name app-demo-1
   
   #check the pods and services
   kubectl get all

   

3. You can access the app using EXTERNAL-IP of service/app-demo-1 and Nginx landing page will show up.

   

Nginx - Ingress Controller Installation and Configuration

Installation Step by Step

1. Add nginx repository to helm

   helm repo add nginx-stable https://helm.nginx.com/stable

2. Check the repo list

   helm repo ls

3. Search the nginx

   helm search repo nginx

4. Pull the nginx-ingress from the repository, it will download tgz file.

   # run this in the home dir or other directory
   helm pull nginx-stable/nginx-ingress
   # extract the tgz
   tar xvf nginx-ingress-*

5. Change directory to nginx-ingress and edit values.yaml file.

   cd nginx-ingress
   
   # edit values.yaml
   vim values.yaml
   
   # locate ingressClass and change the variable below to true
   ...
   ingressClass:
   ...
     setAsDefaultIngress: true
   ...

6. Install nginx-ingress using helm

   helm -n ingress install nginx-ingress -f values.yaml . --debug --create-namespace

7. Check the installation

   kubectl -n ingress get all

   

8. The EXTERNAL-IP is available and reachable, but since no resources use it, it display 404

   

Testing the Ingress

1. Add bitname repository to helm

   helm repo add bitnami https://charts.bitnami.com/bitnami

2. Check the repo list

   helm repo ls

3. Search the nginx, we will use bitnami/nginx for the webserver nginx

   helm search repo nginx

4. Pull the nginx from the repository, it will download tgz file.

   # run this in the home dir or other directory
   helm pull bitnami/nginx
   # extract the tgz
   tar xvf nginx-* #make sure the nginx not nginx-ingress

5. Change directory to metallb and edit values.yaml file.

   cd nginx
   
   # edit
   vim values.yaml
   
   #locate these variables
   ...
   ingress:
     enabled: true
     ...
     hostname: nginx.demo.local # make sure this FQDN is pointing to the ingress IP
     ...
     ingressClassName: "nginx" # check using `kubectl get ingressclass`
   ...

6. Install metallb using helm

   helm -n demo install demo-app -f values.yaml . --debug --create-namespace

7. Check the status, if the status still init, wait until running.

   kubectl -n demo get all
   kubectl -n demo get ingress

   

8. If you configure the FQDN in DNS or /etc/hosts correctly to ingress IP address, it will show like this

   

CEPH CSI - StorageClass Installation and Configuration

TODO - i don’t have CEPH cluster yet 🙈

Tags:

• k8s
• k3s
• kubernetes
• proxmox
• ubuntu