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How to install kubernetes for Tracardi

We advice to use k3s as a simple K8s cluster.

To do so you will need at lease 3 machines or VPSes.

To install a k3s cluster with at least 3 nodes, follow these steps:

  1. Install k3s on the First Node: On your main server node (Master), run the following command to install k3s: 

    curl -sfL https://get.k3s.io | sh -
    This will install k3s and start it as a service. To get the token required for adding agent nodes, run: 
    sudo cat /var/lib/rancher/k3s/server/node-token

  2. Install k3s on Agent Nodes: On each of the remaining nodes (agent nodes), run the following command, replacing <SERVER_IP> with the IP address of your server node and <NODE_TOKEN> with the token retrieved from the server node: 

    curl -sfL https://get.k3s.io | K3S_URL=https://<SERVER_IP>:6443 K3S_TOKEN=<NODE_TOKEN> sh -

  3. Verify the Cluster: After installing k3s on all nodes, verify the cluster status on the server node by running: 

    kubectl get nodes
    This command should list all nodes in the cluster, including the master and agent nodes, showing their status as " Ready".

How to manage k3s from outside the cluster

Managing a K3s (Lightweight Kubernetes) cluster from outside the cluster involves configuring kubectl to access the cluster remotely. Here's a step-by-step guide on how to do this:

1. Set Up K3s Cluster

Make sure your K3s cluster is running and you have access to the kubeconfig file, which is usually located at /etc/rancher/k3s/k3s.yaml on the master node.

2. Expose the K3s API Server

Ensure that port 6443 (default port for the Kubernetes API server) is open on your firewall and accessible from your remote location.

3. Copy and modify /etc/rancher/k3s/k3s.yaml` file

Copy the remote file /etc/rancher/k3s/k3s.yaml (from server master node) to you local computer (best location on your local computer is: ~/.kube/config). Modify the file (~/.kube/config). Update the server field to use the external IP or DNS name of the master node:

server: https://YOUR_EXTERNAL_IP:6443

This will tell you computer where the k3s cluster is located.

4. Configure kubectl

  1. Set the KUBECONFIG Environment Variable:
export KUBECONFIG=~/.kube/config
  1. Test the Connection: Verify that you can connect to the K3s cluster from your local computer.
kubectl get nodes

4. Secure the Connection

For production environments, it is important to secure the API server:

  • Use a VPN: Set up a VPN to securely connect to your internal network.
  • TLS Certificates: Ensure that TLS certificates are properly configured and trusted.
  • Firewall Rules: Restrict access to the API server to specific IP addresses.

Example Commands

  1. Copy k3s.yaml to Local Machine:
scp user@master-node:/etc/rancher/k3s/k3s.yaml ~/.kube/config
  1. Edit k3s.yaml:

Update the server field to use the external IP or DNS name:

server: https://YOUR_EXTERNAL_IP:6443
  1. Set KUBECONFIG:
export KUBECONFIG=~/.kube/config
  1. Test Connection:
kubectl get nodes
Example output for 3 node cluster
NAME      STATUS   ROLES                  AGE   VERSION
node-02   Ready    <none>                 1s   v1.29.4+k3s1
node-03   Ready    <none>                 1s   v1.29.4+k3s1
node-01   Ready    control-plane,master   1s   v1.29.4+k3s1
  1. Your K3s cluster is ready: Now you can use kubectl to manage the kluster from you machine.

Other K8s Clients

We recommend OpenLens which is the open-source version of Lens, a popular Kubernetes IDE. Installing OpenLens involves downloading the appropriate package for your operating system and setting it up. Here are the steps to install OpenLens on different operating systems:

For Windows

  1. Download the Installer:

  2. Run the Installer:

    • Double-click the downloaded .exe file.
    • Follow the installation prompts to complete the setup.

For macOS

  1. Download the Installer:

  2. Install OpenLens:

    • Open the downloaded .dmg file.
    • Drag the OpenLens application to the Applications folder.

For Linux

  1. Download the Installer:

  2. Install OpenLens:

    • For .AppImage: 
      chmod +x OpenLens-x.y.z.AppImage
./OpenLens-x.y.z.AppImage
    • For .deb (Debian/Ubuntu): 
      sudo dpkg -i OpenLens-x.y.z.deb
    • For .rpm (Fedora/CentOS/RHEL): 
      sudo rpm -i OpenLens-x.y.z.rpm

Launch OpenLens

After installation, you can launch OpenLens from your application launcher or by running openlens from the terminal, depending on your operating system.

Connecting to a Kubernetes Cluster

  1. Open OpenLens:

    • Launch OpenLens from your installed applications.

  2. Add Cluster:

    • Click on "Add Cluster" and follow the prompts to connect to your Kubernetes cluster. You will need the kubeconfig file for your cluster.

  3. Manage Clusters:

    • Once connected, you can manage and monitor your Kubernetes clusters using the OpenLens interface.