Step-by-Step Guide: Install CentOS, Docker CE, and Build a Kubernetes Cluster

Prepare CentOS

Install net-tools and disable the firewall:

# yum install -y net-tools
# systemctl stop firewalld && systemctl disable firewalld
# setenforce 0
# sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config

Install Docker CE

Use the community edition of Docker.

# yum install -y yum-utils device-mapper-persistent-data lvm2
# yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
# yum-config-manager --disable docker-ce-edge
# yum makecache fast
# yum -y install docker-ce
# systemctl start docker
# docker run hello-world

Install Kubernetes Packages

Install kubelet, kubeadm, kubectl and kubernetes-cni from the Alibaba Cloud repository.

# cat >> /etc/yum.repos.d/kubernetes.repo <<EOF
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=0
EOF
# yum install -y kubectl kubelet kubeadm kubernetes-cni

Configure cgroups and cAdvisor

Change the kubelet cgroup driver to cgroupfs and set the cAdvisor port to 4194.

# vi /etc/systemd/system/kubelet.service.d/10-kubeadm.conf
# Add: Environment="KUBELET_CGROUP_ARGS=--cgroup-driver=cgroupfs"
# Add: Environment="KUBELET_CADVISOR_ARGS=--cadvisor-port=4194"
# systemctl enable kubelet && systemctl start kubelet

Initialize the Master Node

Reset any previous state and run kubeadm init with the desired API server address, Kubernetes version, and pod network CIDR.

# kubeadm reset && kubeadm init \
    --apiserver-advertise-address=192.168.0.100 \
    --kubernetes-version=v1.7.5 \
    --pod-network-cidr=10.200.0.0/16

After initialization, copy the admin kubeconfig for regular user access:

# mkdir -p $HOME/.kube
# cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
# chown $(id -u):$(id -g) $HOME/.kube/config

Deploy Flannel Networking

Pull the Flannel image and apply the manifest files:

# docker pull quay.io/coreos/flannel:v0.8.0-amd64
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.8.0/Documentation/kube-flannel.yml
# kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.8.0/Documentation/kube-flannel-rbac.yml

Join Worker Nodes

On each worker, run the join command printed by kubeadm init (example below):

# kubeadm join --token 0696ed.7cd261f787453bd9 192.168.0.100:6443

Verify the Cluster

Check component health and node status:

# kubectl get cs
# kubectl get nodes
# kubectl get pods --all-namespaces

Troubleshooting

If you encounter “The connection to the server localhost:8080 was refused”, set the kubeconfig environment variable:

# echo 'export KUBECONFIG=/etc/kubernetes/admin.conf' >> ~/.bash_profile
# source ~/.bash_profile

All steps above provide a complete, reproducible process to set up a functional Kubernetes cluster on CentOS.