Use Rancher deployment to manage THE K8S cluster.

Let’s have a snack today. It doesn’t involve K8S. Rancher is a great way to deploy and manage a K8S cluster.

Install the K8S cluster using Rancher

Hosting plan

The host name	role	The IP address	Based on the software
k8s-rancher	Manage the K8S cluster	192.168.242.109	docker-ce
k8s-master	K8s Primary node of the cluster	192.168.242.108	docker-ce
k8s-worker-node01	K8s secondary node 1	192.168.242.107	docker-ce
k8s-worker-node02	K8s secondary node 2	192.168.242.106	docker-ce

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Host Name indicates the host on which the operation is performed.

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Docker-ce is installed on each machine, and the installation command is in

Container Technology Docker- From earth to Heaven

Already mentioned. It is also provided here:

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



yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo



yum makecache fast



yum -y install docker-ce



systemctl enable docker



sudo mkdir -p /etc/docker

sudo tee /etc/docker/daemon.json <<-'EOF'

{

  "registry-mirrors": ["https://yours.mirror.aliyuncs.com"]

}

EOF

sudo systemctl daemon-reload

sudo systemctl restart docker

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Install the rancher

On host K8S-Rancher, run the following command:

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

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If you cannot access the http://192.168.242.109 rancher page, use docker ps to observe the “container running status” of docker rancher

Docker logs container ID

Check the log and find the following error message:

rancher must be ran with the --privileged flag when running outside of kubernetes

This is caused by the permission issue of Selinux. When launching the container, it is necessary to add –privileged, delete the container created just now and run it again:

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

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If you find that the container restarts frequently after running for a while, you can increase the memory size. My VM was originally given 1 GB of memory, but the VM keeps restarting. After adjusting the memory size, the fault is rectified.

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Open the page:

The Rancher page can be displayed in Chinese, and the next step is to create a cluster with a click of the mouse.

Click Add Cluster to enter the page for creating a K8S cluster:

Click Customize:

Enter the cluster name, select the K8S version, and click Next to enter:

As shown below, operations are required on k8S-Master:

Now go to the Rancher management page, click Global, see the k8S cluster created just now:

Click cluster, enter, and click host:

You can see various states during the cluster deployment process. When the green Active state appears, it indicates that the Master node of the K8S cluster is successfully created:

Continue editing the cluster and copy the command below to add the K8S slave node:

Run the following commands on hosts K8s-worker-node01 and k8s-worker-node02:

sudo docker run -d --privileged --restart=unless-stopped --net=host -v /etc/kubernetes:/etc/kubernetes -v /var/run:/var/run rancher-agent:v2.5.3 --server https://192.168.242.109 --token 84dphjc9v2949f887gtfxwvk2fhnv7xjlqq84nqb2r565kqn7qnxdp --ca-checksum e4d1715ec0295d2e9e1fbc3bba3386529cdf4e8b1be9e5b8c3b48acb1bd679f3 --worker

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It is important to note that the runtime is slow, and once the container is up, Rancher will need to perform various health checks on the cluster nodes. This process will depend on your machine’s CPU, memory, and network configuration.

Final cluster status: