How to Install Rancher on CentOS 7

Rancher is an open-source platform that simplifies the deployment and management of Kubernetes clusters. Whether you are a Kubernetes user or just getting started, Rancher provides the tools to manage multiple clusters across different environments.

In this article, we will discuss the steps required to install Rancher on a CentOS 7 operating system.

Prerequisites

Before you begin install Rancher CentOS ensure you have the following:

1. A CentOS 7 system with root or sudo access.
2. A minimum of 2 CPU cores and 4GB of RAM.
3. Docker installed on your system.
4. Access to the internet to download necessary packages.

Installing Rancher on CentOS 7

Following are the steps to install Rancher on the CentOS 7 operating system:

Step 1: Update System

Firstly, check your CentOS version then ensure that your system is up to date by running the following commands:

sudo yum update -y && sudo reboot

Step 2: Install Docker

Rancher runs as a Docker container, so you’ll need to have Docker installed. Follow these steps to install Docker on CentOS 7:

To install the required packages type the following command:

sudo yum install -y yum-utils device-mapper-persistent-data lvm2

Add the Docker CE repository:

sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

Then install Docker with the following command:

sudo yum install -y docker-ce

Start and check the status of Docker by typing the following:

sudo systemctl start docker && sudo systemctl status docker

You can also verify Docker installation by checking its version:

docker --version

Step 3: Install Rancher

With Docker running, you can now install Rancher. Rancher runs on a single Docker container, and it’s straightforward to set up.

Pull the Rancher image with the following:

sudo docker pull rancher/rancher:latest

Run the Rancher container by typing the following:

sudo docker run -d --restart=unless-stopped -p 80:80 -p 443:443 rancher/rancher:latest

This command will start a Rancher container and bind it to ports 80 and 443 on your host.

Step 4: Access Rancher UI

Once the Rancher container is running, you can access the Rancher UI. Open a web browser and navigate to the following URL:

http://<your-server-ip>/

You will be greeted with the Rancher setup page. Follow the instructions to complete the setup.

Step 5: Configure Rancher

After accessing the Rancher UI, you will need to perform some initial configuration. Here are the steps:

1. Set up an Admin account

Create a username and password for the admin account. Then, log in with the admin credentials.

2. Add your first cluster

Rancher supports various types of Kubernetes clusters, including hosted Kubernetes like GKE, AKS, EKS, custom clusters, and imported clusters. Follow the Rancher UI to set up your first cluster.

3. Configure Global Settings

Adjust settings such as authentication providers, certificates, and other global configurations as per your requirements.

Step 6: Install kubectl

To interact with your Kubernetes clusters, you will need to install kubectl, the Kubernetes command-line tool.

Download the kubectl binary with the following:

curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl

Make the kubectl binary executable:

chmod +x ./kubectl

Move the binary to your PATH:

sudo mv ./kubectl /usr/local/bin/kubectl

Verify kubectl installation by checking it’s version:

kubectl version --client

Step 7: Connect kubectl to Cluster

After setting up your cluster in Rancher, you can connect kubectl to your Kubernetes cluster by downloading the kubeconfig file from the Rancher UI.

Go to the Rancher UI and navigate to the cluster you want to manage. Click on “Kubeconfig File” and download it.

Set the KUBECONFIG environment variable to point to your downloaded kubeconfig file:

export KUBECONFIG=/path/to/your/kubeconfig/file

Verify the connection by typing the following command:

kubectl get nodes

Troubleshooting

Here are some common issues you might encounter during the CentOS install Rancher process and how to resolve them:

Docker Service Fails

• Ensure you are using the correct repository and Docker version for CentOS 7.
• Check the Docker service status for error messages.

Rancher Container Fails

• Verify that the Docker daemon is running properly.
• Check the container logs for any errors.

Unable to Access Rancher UI

• Ensure that your firewall settings are not blocking ports 80 and 443.
• Verify that the Rancher container is running and bound to the correct ports.

Conclusion

Installing Rancher on CentOS 7 is a straightforward process that can significantly streamline the management of your Kubernetes clusters. By following this guide, you should be able to get Rancher up and running in no time. Remember, the key to a successful installation is ensuring all prerequisites are met and following each step carefully. Once installed, Rancher will provide a powerful interface for managing your Kubernetes environments, making container orchestration more accessible and efficient.

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