Install OpenELB on K3s

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

NOTE

In a Kubernetes cluster, you only need to install OpenELB once. After the installation is complete, a openelb-manager Deployment that contains a openelb-manager Pod is installed in the cluster. The openelb-manager Pod implements the functionality of OpenELB for the entire Kubernetes cluster.
After the installation is complete, you can scale the openelb-manager Deployment and assign multiple OpenELB replicas (openelb-manager Pods) to multiple cluster nodes to ensure high availability. For details, see Configure Multiple OpenELB Replicas.

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

Log in to the master node of the K3s Kubernetes cluster over SSH and run the following command:
```
kubectl apply -f https://raw.githubusercontent.com/openelb/openelb/master/deploy/openelb.yaml
```
Run the following command to edit the openelb-manager Deployment:
```
kubectl edit deployment openelb-manager -n openelb-system
```

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.

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

To delete OpenELB, log in to the master node of the K3s Kubernetes cluster and run the following command:
```
kubectl delete -f https://raw.githubusercontent.com/openelb/openelb/master/deploy/openelb.yaml
```

NOTE

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

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

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.

Run the following commands to install OpenELB:

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

Run the following command to edit the openelb-manager Deployment:
```
kubectl edit deployment openelb-manager
```

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.

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

To delete OpenELB, run the following command:
```
helm delete openelb
```

NOTE

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

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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Last modified February 23, 2022: rename to openelb in English document (5c5431f)