Step by Step To Create a K8S Cluster

Step by Step To Create a K8S Cluster

Refer:

https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/
https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/
https://kubernetes.io/zh/docs/setup/production-environment/container-runtimes/
https://github.com/maguowei/gotok8s
https://www.cnblogs.com/xuxinkun/p/11025020.html

1. Create an Vitural Machine with image CentOS-8.3.2011-x86_64-minimal.iso

2. Install Container runtimes (Docker)

refer: https://docs.docker.com/engine/install/centos/

# Uninstall old versions  
sudo yum remove docker 
                  docker-client 
                  docker-client-latest 
                  docker-common 
                  docker-latest 
                  docker-latest-logrotate 
                  docker-logrotate 
                  docker-engine  
  
# Install using the repository  
  
#  1. Set up the repository  
sudo yum install -y yum-utils  
sudo yum-config-manager   
    --add-repo   
    https://download.docker.com/linux/centos/docker-ce.repo  

## yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
  
#  2. Install Docker Engine  
sudo yum install docker-ce docker-ce-cli containerd.io  
  
#  3. 配置 Docker 守护程序，尤其是使用 systemd 来管理容器的 cgroup  
  
sudo mkdir /etc/docker  
cat <<EOF | sudo tee /etc/docker/daemon.json  
{  
  "exec-opts": ["native.cgroupdriver=systemd"],  
  "log-driver": "json-file",  
  "log-opts": {  
    "max-size": "100m"  
  },  
  "storage-driver": "overlay2",
  "registry-mirrors": ["http://hub-mirror.c.163.com"]
}  
EOF
  
#  4. 重新启动 Docker 并在启动时启用  
sudo systemctl enable docker  
sudo systemctl daemon-reload  
sudo systemctl restart docker  

3. Letting iptables see bridged traffic

cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf  
br_netfilter  
EOF
  
cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf  
net.bridge.bridge-nf-call-ip6tables = 1  
net.bridge.bridge-nf-call-iptables = 1  
EOF  
sudo sysctl --system  

4. Disable Firewalld 端口开放

systemctl disable firewalld  
systemctl stop firewalld  
  

https://www.cnblogs.com/larrypeng/p/11950498.html 关闭swap

5. Installing kubeadm, kubelet and kubectl

cat <<EOF | sudo tee /etc/yum.repos.d/kubernetes.repo  
[kubernetes]  
name=Kubernetes  
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-$basearch  
enabled=1  
gpgcheck=1  
repo_gpgcheck=1  
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg  
exclude=kubelet kubeadm kubectl  
EOF  

# CentOS/RHEL/Fedora 国内
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
exclude=kubelet kubeadm kubectl  
EOF
  
# Set SELinux in permissive mode (effectively disabling it) 禁用SELinux, 让容器可以读取主机文件系统 which is needed by pod networks for example  
sudo setenforce 0
sudo sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config  
  
sudo yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes  
  
sudo systemctl enable --now kubelet  
  

6. Configuring the kubelet cgroup driver

cat <<EOF | sudo tee ./kubeadm-config.yaml  
# kubeadm-config.yaml  
kind: ClusterConfiguration  
apiVersion: kubeadm.k8s.io/v1beta2  
kubernetesVersion: v1.21.1
imageRepository: registry.aliyuncs.com/google_containers  
networking: 
  podSubnet: "10.100.0.1/24"  
---  
kind: KubeletConfiguration  
apiVersion: kubelet.config.k8s.io/v1beta1  
cgroupDriver: systemd  
EOF  

docker pull coredns/coredns:1.8.0
docker tag coredns/coredns:1.8.0 registry.aliyuncs.com/google_containers/coredns/coredns:v1.8.0
  
kubeadm init --config kubeadm-config.yaml  

[init] Using Kubernetes version: v1.21.0
[preflight] Running pre-flight checks
        [WARNING FileExisting-tc]: tc not found in system path `dnf install -y iproute-tc` [CentOS-8]
error execution phase preflight: [preflight] Some fatal errors occurred:
        [ERROR NumCPU]: the number of available CPUs 1 is less than the required 2
        [ERROR Mem]: the system RAM (744 MB) is less than the minimum 1700 MB
        [ERROR Swap]: running with swap on is not supported. Please disable swap `swapoff -a`
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`    
To see the stack trace of this error execute with --v=5 or higher  

Run

kubeadm init --config kubeadm-config.yaml  

[init] Using Kubernetes version: v1.21.1
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local localhost.localdomain] and IPs [10.96.0.1 192.168.0.2]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [localhost localhost.localdomain] and IPs [192.168.0.2 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost localhost.localdomain] and IPs [192.168.0.2 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Starting the kubelet
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[apiclient] All control plane components are healthy after 14.006711 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.21" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Skipping phase. Please see --upload-certs
[mark-control-plane] Marking the node localhost.localdomain as control-plane by adding the labels: [node-role.kubernetes.io/master(deprecated) node-role.kubernetes.io/control-plane node.kubernetes.io/exclude-from-external-load-balancers]
[mark-control-plane] Marking the node localhost.localdomain as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: qrjh2f.agl6zjgrhky7x105
[bootstrap-token] Configuring bootstrap tokens, cluster-info ConfigMap, RBAC Roles
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to get nodes
[bootstrap-token] configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy

Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

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

Alternatively, if you are the root user, you can run:

  export KUBECONFIG=/etc/kubernetes/admin.conf

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 192.168.0.2:6443 --token qrjh2f.agl6zjgrhky7x105 
        --discovery-token-ca-cert-hash sha256:73e9c5cecfc31872a9c91c404ad92843f30c775d59651b81735fd76bb21eaf8d

Computer restart but IP all Changed.
Set CentOS 8 Static Ip: https://www.cnblogs.com/lidezhen/p/13520728.html
Hyper-V Vitural Machine Static Ip: https://www.cnblogs.com/kasnti/p/11727755.html