Install OpenELB on K3s

This document describes how to use kubectl and Helm to install and delete OpenELB in a K3s Kubernetes cluster.

Prerequisites

• You need to prepare a K3s Kubernetes cluster, and ensure that the Kubernetes version is 1.15 or later. OpenELB requires CustomResourceDefinition (CRD) v1, which is only supported by Kubernetes 1.15 or later. OpenELB is designed to be used in bare-metal Kubernetes environments. However, you can also use a cloud-based K3s Kubernetes cluster for learning and testing.

• If you use Helm to install OpenELB, ensure that the Helm version is Helm 3.

Install OpenELB Using kubectl

1. Log in to the master node of the K3s Kubernetes cluster over SSH and run the following command:

   We recommend using the stable release version in a production environment. Please use the following command to download the installation script for the stable version:

   wget https://raw.githubusercontent.com/openelb/openelb/release-0.5/deploy/openelb.yaml
   kubectl apply -f openelb.yaml
   

   If you are interested in the latest features of the master branch and want to use the development version, use the following command to download the deployment script:

   wget https://raw.githubusercontent.com/openelb/openelb/master/deploy/openelb.yaml
   kubectl apply -f openelb.yaml
   

2. Run the following command to edit the openelb-manager Deployment:

   kubectl edit deployment openelb-manager -n openelb-system
   

3. Change port 443 to a different value (for example, 30443) to avoid a port conflict with K3s:

   spec:
     template:
       spec:
         containers:
         - args:
           - --webhook-port=443 # Change the port number.
           ports:
           - containerPort: 443 # Change the port number.
             hostPort: 443 # Change the port number.
   

   NOTE

   By default, both OpenELB and K3s use port 443. Therefore, you need to change port 443 of OpenELB to avoid the port conflict. For details, see the official K3s document.

4. Run the following command to check whether the status of openelb-manager is READY: 1/1 and STATUS: Running. If yes, OpenELB has been installed successfully.

   kubectl get po -n openelb-system
   

   It should return something like the following.

   NAME                               READY   STATUS      RESTARTS   AGE
   openelb-admission-create-tjsqm     0/1     Completed   0          41s
   openelb-admission-patch-n247f      0/1     Completed   0          41s
   openelb-manager-74c5467674-bx2wg   1/1     Running     0          41s
   

Delete OpenELB Using kubectl

1. To delete OpenELB, log in to the master node of the K3s Kubernetes cluster and run the following command:

   kubectl delete -f openelb.yaml
   

   NOTE

   Before deleting OpenELB, you must first delete all Services that use OpenELB.

2. Run the following command to check the result. If the openelb-system namespace does not exist, OpenELB has been deleted successfully.

   kubectl get ns
   

Install OpenELB Using Helm

1. Log in to the master node of the K3s Kubernetes cluster over SSH and run the following command to configure the environment variable:

   export KUBECONFIG=/etc/rancher/k3s/k3s.yaml
   

   NOTE

   You need to configure this environment variable so that Helm can reach the K3s Kubernetes cluster. For details, see the official K3s document.

2. Run the following commands to install OpenELB:

   helm repo add stable https://charts.kubesphere.io/stable
   helm repo update
   helm install openelb stable/openelb
   

3. Run the following command to edit the openelb-manager Deployment:

   kubectl edit deployment openelb-manager
   

4. Change port 443 to a different value (for example, 30443) to avoid a port conflict with K3s:

   spec:
     template:
       spec:
         containers:
         - args:
           - --webhook-port=443 # Change the port number.
           ports:
           - containerPort: 443 # Change the port number.
             hostPort: 443 # Change the port number.
   

   NOTE

   By default, both OpenELB and K3s use port 443. Therefore, you need to change port 443 of OpenELB to avoid the port conflict. For details, see the official K3s document.

5. Run the following command to check whether the status of openelb-manager is READY: 1/1 and STATUS: Running. If yes, OpenELB has been installed successfully.

   kubectl get po -A
   

   It should return something like the following.

   NAMESPACE        NAME                              READY   STATUS      RESTARTS   AGE
   openelb-system   openelb-admission-create-m2p52    0/1     Completed   0          32s
   openelb-system   openelb-admission-patch-qmvnq     0/1     Completed   0          31s
   openelb-system   openelb-manager-74c5467674-pgtmh  1/1     Running     0          32s
   ... ...
   

Delete OpenELB Using Helm

1. To delete OpenELB, run the following command:

   helm delete openelb
   

   NOTE

   Before deleting OpenELB, you must first delete all Services that use OpenELB.

2. Run the following command to check the result. If the OpenELB application does not exist, OpenELB has been deleted successfully.

   helm ls
   

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