Integrate Kubernetes Engine cluster with Rancher

Easily manage multi-cluster environments by integrating Rancher with Kakao Cloud's Kubernetes Engine service.

info

• Estimated time: 30 minutes
  
• User environment
  • Recommended OS: Ubuntu
  • Region: kr-central-2
• Prerequisites
  • Access Key

About this scenario

This tutorial provides guidance on integrating Kubernetes Engine with Rancher for efficient multi-cluster management. Rancher is a powerful open-source platform that enables unified management of Kubernetes clusters across diverse environments, including on-premises and cloud infrastructures. With Rancher, you can intuitively manage multi-cluster environments, efficiently deploy workloads across clusters, and monitor their performance.

This tutorial covers:

• Installing and integrating Rancher with a Kubernetes Engine cluster
• Managing clusters via the Rancher web console
• Efficient operation of multi-cluster environments

caution

• Ensure that you meet the prerequisites and the conditions listed in Before you start before proceeding.
• Note that Rancher usage and configuration are not officially supported by Kakao Cloud. Refer to the official Rancher documentation for detailed information.

Before you start

To smoothly follow this tutorial, prepare the following:

1. Prepare kubernetes cluster

A Kubernetes Engine cluster with Calico CNI must be available for Rancher integration. Refer to the Kubernetes Engine cluster setup tutorial to configure the cluster, and complete the kubectl setup for managing Kubernetes Engine.

2. Set up VM for Rancher installation

A public-facing VM instance is required to install Rancher. This VM must be able to communicate with the worker nodes in the cluster. Configure communication by adjusting VM security group settings and Kubernetes Engine node pool security group settings.

3. Configure network and ports

Control network access between Rancher and Kubernetes Engine using security groups and open necessary ports for communication. Refer to the official Rancher port requirements and configure security group rules accordingly.

Getting started

Step 1. Install Rancher on VM instance

Install Rancher as a Docker container on a Kakao Cloud VM instance and access the web console.

1. Connect to the VM instance and install Rancher using Docker.

   sudo apt update -y
   sudo apt install docker.io
   sudo docker run -d --restart=unless-stopped -p 80:80 -p 443:443 --privileged rancher/rancher
   info

   For various installation methods, refer to the official Rancher installation guide.

2. Verify Rancher web console login password. To check the Rancher web console login password, run the following Docker commands.

   To check the Rancher web console login password, run the following Docker commands:

   sudo docker ps # Check the Rancher container ID
   sudo docker logs ${CONTAINER_ID} | grep "Bootstrap Password"

3. Access Rancher web console. Open the Rancher web console in a browser using the public IP address of the virtual machine.

   http://${VM_PUBLIC_IP}

   환경변수	설명
   VM_PUBLIC_IP🖌︎	Check public IP in Virtual Machine > Instances tab

Step 2. Download Rancher integration YAML file

After logging in to the Rancher web console and completing the setup, download the YAML file required for integration with Kubernetes Engine.

1. Log in using the password retrieved in Step 2.

2. Change the admin account password and log in.

   Enter the private IP of the VM instance as the Server URL.

   # Server URL
   https://${VM_PRIVATE_IP}

   환경변수	설명
   VM_PRIVATE_IP🖌︎	Check private IP in Virtual Machine > Instances tab

3. To integrate Rancher with Kakao Cloud Kubernetes Engine, download the YAML file. Navigate to Cluster Management > Import Existing > Generic, enter the required values, and click Create.

   Download the YAML file by running the URL provided in the Rancher web console on the VM where Rancher is installed.

     # yaml file download
     curl --insecure -sfL https://${VM_PRIVATE_IP}/v3/import/9ppxrgd6rfgz6xf6wz2q6znk5whjz2vnbwm5scn8slwwbz7wm6fc_c-m-67n5s5qq.yaml > kakaocloud_ke.yaml

   The downloaded YAML file creates Kubernetes resources for Rancher integration. Below is an example:

     # Sample YAML file
     ---
     apiVersion: rbac.authorization.k8s.io/v1
     kind: ClusterRole
     ...
     ---
     apiVersion: rbac.authorization.k8s.io/v1
     kind: ClusterRoleBinding
     ...
     ---
     apiVersion: v1
     kind: ServiceAccount
     metadata:
       name: cattle
       namespace: cattle-system
     ---
     apiVersion: rbac.authorization.k8s.io/v1
     kind: ClusterRoleBinding
     ...
     ---
     apiVersion: v1
     kind: Secret
     ...
     ---
     apiVersion: rbac.authorization.k8s.io/v1
     kind: ClusterRole
     metadata:
       name: cattle-admin
     ...
     ---
     apiVersion: apps/v1
     kind: Deployment
     metadata:
       name: cattle-cluster-agent
       namespace: cattle-system
     ...
     ---
     apiVersion: v1
     kind: Service
     metadata:
       name: cattle-cluster-agent
       namespace: cattle-system
     ...

Step 3. Apply YAML file to Kubernetes Engine

Apply the YAML file to Kubernetes Engine to complete the integration with Rancher.

1. Apply the downloaded script using the kubectl command. This command creates Kubernetes resources required for integrating Rancher with Kubernetes Engine.

   kubectl apply -f kakaocloud_ke.yaml
   
   

2. Since the master nodes are not part of the container network, you need to configure a WebHook. Deploy a WebHook YAML file with the hostNetwork=true setting.

   rancher_webhook.yaml

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: rancher-config
     namespace: cattle-system
     labels:
       app.kubernetes.io/part-of: "rancher"
   data:
     rancher-webhook: '{"global": {"hostNetwork": true}}'

3. Apply rancher_webhook.yaml file to Kakao Cloud Kubernetes Engine using the kubectl command.

    kubectl apply -f rancher_webhook.yaml

4. Verify that Kubernetes Engine is successfully connected to Rancher and is in the Active state. At this point, confirm that the Master Nodes are also visible in Rancher.

5. Check and manage the Kubernetes Engine, including Master Nodes, from the Rancher web console.