K8S集群安装（kubeadm）

环境

系统：CentOS 7.8

准备

• 安装Docker

• 关闭swap

• 修改内核运行参数

cat << EOF | tee /etc/sysctl.d/99-kubernetes-cri.conf
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-ip6tables = 1
net.ipv4.ip_forward = 1
EOF

sysctl --system

• 添加K8S Yum源

cat << EOF | tee /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
EOF

• 安装K8S

yum install -y kubelet kubeadm kubectl
systemctl enable kubelet

Master节点

• 初始化K8S集群

kubeadm init --pod-network-cidr 10.244.0.0/16 --kubernetes-version latest

# 如官方源太慢导致初始化卡住，可更换阿里云源（非必需）
kubeadm init --image-repository=registry.aliyuncs.com/google_containers --pod-network-cidr 10.244.0.0/16 --kubernetes-version latest

--pod-network-cidr 与CNI插件有关，此处使用Flannel
--kubernetes-version 为K8S指定版本，如 stable-1.21
--control-plane-endpoint 为control-plane指定 IP 或 DNS

如出现错误：error: failed to run Kubelet: failed to create kubelet: misconfiguration: kubelet cgroup driver: "cgroupfs" is different from docker cgroup driver: "systemd"
解决方法：更换docker cgroup driver为systemd

成功后会输出

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 192.168.10.10:6443 --token r4ui2y.ord9liberrbz7qhm \
        --discovery-token-ca-cert-hash sha256:b2338948674f696f03bc409d13f940938e17eb04800e605e3a8226597d564263

• 配置集群访问认证

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

• 安装CNI插件
  此处使用Flannel

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

Worker节点

• 加入集群

kubeadm join 192.168.10.10:6443 --token r4ui2y.ord9liberrbz7qhm \
        --discovery-token-ca-cert-hash sha256:b2338948674f696f03bc409d13f940938e17eb04800e605e3a8226597d564263

其它

• 允许Master节点运行pod

# 解除限制
kubectl taint nodes --all node-role.kubernetes.io/master-

# 恢复默认
kubectl taint nodes NODE_NAME node-role.kubernetes.io/master=true:NoSchedule

• 使用HPA时，需安装插件Metrics Server