目录

高可用拓扑

安装前配置

安装 Kubeadm（ALL NODE）

部署外部 etcd 节点

安装HAProxy代理服务

初始化主节点（MASTER NODE）

初始化Master-01

安装网络-Flannel

其他Master节点接入Master集群

Work Node加入集群（WORK NODE）

通过kubernetes调度启动容器 (验证集群是否可用）

参考链接

高可用拓扑

    

IP地址	角色1	角色2	K8S版本	ETCD版本
master-01/192.168.35.7	Master节点	ETCD节点	v1.20.4	v3.4.14
master-02/192.168.35.8	Master节点	ETCD节点	v1.20.4	v3.4.14
master-03/192.168.35.9	Master节点	ETCD节点	v1.20.4	v3.4.14
node-01/192.168.35.10	Node节点	HAProxy代理	v1.19.3	-

安装前配置

见《【K8S 一】使用kubeadm工具快速部署Kubernetes集群(单Master)》

安装 Kubeadm（ALL NODE）

见《【K8S 一】使用kubeadm工具快速部署Kubernetes集群(单Master)》

部署外部 etcd 节点

注：Kubernetes1.20.4版本，初始化Master-01之后，其他Master节点加入Cluster创建ETCD Pod失败，所以我手动部署了外部etcd集群。不知道是否是1.20.4版本的BUG还是我操作有误，如有朋友使用local etcd集群搭建成功，可以给我留言，谢过~

见《【K8S etcd篇】部署etcd 3.4.14 集群》

安装HAProxy代理服务

安装HAProxy
# yum -y install haproxy
配置HAProxy
# vi /etc/haproxy/haproxy.cfg
global
    log         127.0.0.1 local2
    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

defaults
    mode                    tcp
    log                     global
    retries                 3
    timeout connect         10s
    timeout client          1m
    timeout server          1m

frontend kube-apiserver
    bind *:6443 # 指定前端端口
    mode tcp
    default_backend master

backend master # 指定后端机器及端口，负载方式为轮询
    balance roundrobin
    server master-01  192.168.35.7:6443 check maxconn 2000
    server master-02  192.168.35.8:6443 check maxconn 2000
    server master-03  192.168.35.9:6443 check maxconn 2000

启动和设置开机自启动
# systemctl start haproxy
# systemctl enable haproxy

初始化主节点（MASTER NODE）

kubeadm config print init-defaults --component-configs KubeProxyConfiguration > kubeadm-config.yaml

#修改初始化配置文件

apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: liuyll.0123456789abcdef
  ttl: 24h0m0s
  usages:
  - signing
  - authentication
kind: InitConfiguration
localAPIEndpoint:
  advertiseAddress: 192.168.35.7
  bindPort: 6443
nodeRegistration:
  criSocket: /var/run/dockershim.sock
  name: master-01
  taints:
  - effect: NoSchedule
    key: node-role.kubernetes.io/master
---
apiServer:
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: 192.168.35.10:6443 ## 如果要部署高可用Master集群，此配置项必须配置。
controllerManager: {}
dns:
  type: CoreDNS
etcd:
  external:
    endpoints:
    - "https://192.168.35.7:2379"
    - "https://192.168.35.8:2379"
    - "https://192.168.35.9:2379"
    caFile: /opt/etcd/tls-certs/ca.pem
    certFile: /opt/etcd/tls-certs/etcd.pem
    keyFile: /opt/etcd/tls-certs/etcd-key.pem
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: v1.20.0
networking:
  dnsDomain: cluster.local
  podSubnet: 172.254.0.0/16
  serviceSubnet: 10.254.0.0/16
scheduler: {}
---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
iptables:
  masqueradeAll: false
ipvs:
  minSyncPeriod: 0s
  scheduler: "rr"
kind: KubeProxyConfiguration
mode: "ipvs"

拷贝到各Master节点，然后执行下面的命令提前下载Kubernetes镜像（kube-apiserver、kube-controller-manager、kube-scheduler、kube-proxy、coredns、pause）：

kubeadm config images pull --config=kubeadm-config.yaml

初始化Master-01

# kubeadm init --config=kubeadm-config.yaml --upload-certs |tee kubeadm-init.log

[init] Using Kubernetes version: v1.20.0
[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 master-01] and IPs [10.254.0.1 192.168.35.7 192.168.35.10]
[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] External etcd mode: Skipping etcd/ca certificate authority generation
[certs] External etcd mode: Skipping etcd/server certificate generation
[certs] External etcd mode: Skipping etcd/peer certificate generation
[certs] External etcd mode: Skipping etcd/healthcheck-client certificate generation
[certs] External etcd mode: Skipping apiserver-etcd-client certificate generation
[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"
[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
[kubelet-check] Initial timeout of 40s passed.
[apiclient] All control plane components are healthy after 62.010428 seconds
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config-1.20" in namespace kube-system with the configuration for the kubelets in the cluster
[upload-certs] Storing the certificates in Secret "kubeadm-certs" in the "kube-system" Namespace
[upload-certs] Using certificate key:
684fca0d14f339aa71c85b9830ea8610db8ec58900bd84678b03e643091d9b89
[mark-control-plane] Marking the node master-01 as control-plane by adding the labels "node-role.kubernetes.io/master=''" and "node-role.kubernetes.io/control-plane='' (deprecated)"
[mark-control-plane] Marking the node master-01 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]
[bootstrap-token] Using token: liuyll.0123456789abcdef
[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/

You can now join any number of the control-plane node running the following command on each as root:

  kubeadm join 192.168.35.10:6443 --token liuyll.0123456789abcdef \
    --discovery-token-ca-cert-hash sha256:49df97b238db81a6a9cbdfce9e22945c49677b71868038ee4829e850bb5411fc \
    --control-plane --certificate-key 684fca0d14f339aa71c85b9830ea8610db8ec58900bd84678b03e643091d9b89

Please note that the certificate-key gives access to cluster sensitive data, keep it secret!
As a safeguard, uploaded-certs will be deleted in two hours; If necessary, you can use
"kubeadm init phase upload-certs --upload-certs" to reload certs afterward.

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

kubeadm join 192.168.35.10:6443 --token liuyll.0123456789abcdef \
    --discovery-token-ca-cert-hash sha256:49df97b238db81a6a9cbdfce9e22945c49677b71868038ee4829e850bb5411fc 

安装网络-Flannel

注：初始化完成Master-01之后，必须先安装网络插件，然后再将其他Master节点加入到Master Cluster，否则Flannel安装时，只有一个Master节点上Flannel Pod创建并启动成功，其他所有节点都会失败：频繁重启。

见《【K8S 一】使用kubeadm工具快速部署Kubernetes集群(单Master)》

其他Master节点接入Master集群

安装完网络插件，执行kubectl get po -n kube-system查看所有Pod都是Running状态之后，根据Master-01初始化回显提示，执行下面的命令将其他的Master节点接入的Cluster。

# kubeadm join 192.168.35.10:6443 --token liuyll.0123456789abcdef \
>     --discovery-token-ca-cert-hash sha256:49df97b238db81a6a9cbdfce9e22945c49677b71868038ee4829e850bb5411fc \
>     --control-plane --certificate-key 684fca0d14f339aa71c85b9830ea8610db8ec58900bd84678b03e643091d9b89
[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[preflight] Running pre-flight checks before initializing the new control plane instance
[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'
[download-certs] Downloading the certificates in Secret "kubeadm-certs" in the "kube-system" Namespace
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[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 master-02] and IPs [10.254.0.1 192.168.35.8 192.168.35.10]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Valid certificates and keys now exist in "/etc/kubernetes/pki"
[certs] Using the existing "sa" key
[kubeconfig] Generating kubeconfig files
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[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"
[check-etcd] Skipping etcd check in external mode
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
[control-plane-join] using external etcd - no local stacked instance added
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[mark-control-plane] Marking the node master-02 as control-plane by adding the labels "node-role.kubernetes.io/master=''" and "node-role.kubernetes.io/control-plane='' (deprecated)"
[mark-control-plane] Marking the node master-02 as control-plane by adding the taints [node-role.kubernetes.io/master:NoSchedule]

This node has joined the cluster and a new control plane instance was created:

* Certificate signing request was sent to apiserver and approval was received.
* The Kubelet was informed of the new secure connection details.
* Control plane (master) label and taint were applied to the new node.
* The Kubernetes control plane instances scaled up.

To start administering your cluster from this node, 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

Run 'kubectl get nodes' to see this node join the cluster.

其他Master节点全部加入到集群之后，执行kubectl get nodes查看：
# kubectl get node
NAME        STATUS   ROLES                  AGE     VERSION
master-01   Ready    control-plane,master   6h15m   v1.20.4
master-02   Ready    control-plane,master   6h11m   v1.20.4
master-03   Ready    control-plane,master   6h10m   v1.20.4

Work Node加入集群（WORK NODE）

见《【K8S 一】使用kubeadm工具快速部署Kubernetes集群(单Master)》

通过kubernetes调度启动容器 (验证集群是否可用）

见《【K8S 一】使用kubeadm工具快速部署Kubernetes集群(单Master)》

参考链接

kubeadm configuration file

kubeadm 使用外部etcd

生产环境-使用部署工具安装 Kubernetes：使用 kubeadm 引导集群

最佳实践-校验节点设置：节点一致性测试