21、Kubernetes核心技术 - 高可用集群搭建（kubeadm+keepalived+haproxy）

k8s集群的高可用主要体现在master相关组件及etcd，master中apiserver是集群的入口，搭建三个master通过keepalived提供一个vip（虚拟IP）实现高可用，并且添加haproxy来为apiserver提供反向代理的作用，这样来自haproxy的所有请求都将轮询转发到后端的master节点上。如果仅仅使用keepalived，当集群正常工作时，所有的流量还是会转发到具有vip（虚拟IP）的那台master上面，因此加上了haproxy使整个集群的master都能参与进来，集群的健壮性更强。

对应架构图如下所示：

简单来说，就是需要满足下面两个条件：

1)、在 node 节点和 master 节点之间，需要一个 LoadBalancer 组件

- 【作用 1】负载均衡
- 【作用 2】检查 master 节点的状态

2)、对外需要一个统一的 VIP（虚拟IP）

- 【作用 1】虚拟 ip 对外进行访问

三、部署环境说明

由于这里使用虚拟机搭建，资源有限，我们采用 2 个 master 节点，2个 node 节点来搭建高可用k8s集群。文中使用到的服务器ip及角色对应如下。

主机名称	ip地址	角色
k8s-vip	192.168.1.39	虚拟ip(vip)
k8s-master-01	192.168.1.35	master
k8s-master-02	192.168.1.36	master
k8s-node-01	192.168.1.37	node
K8s-node-02	192.168.1.38	node

四、高可用集群搭建

(1)、初始化所有节点

所有节点，需关闭防火墙规则，关闭selinux，关闭swap交换、时间同步。

[root@localhost ~]# systemctl stop firewalld
[root@localhost ~]# systemctl disable firewalld
[root@localhost ~]# setenforce 0
[root@localhost ~]# sed -i 's/SELINUX=enforcing/\SELINUX=disabled/' /etc/selinux/config

# 禁用swap, kubeadm会检查当前主机是否禁用了swap，如果启动了swap将导致安装不能正常进行，所以需要禁用所有的swap
[root@localhost ~]# swapoff -a
[root@localhost ~]# sed -ri 's/.*swap.*/#&/' /etc/fstab
[root@localhost ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              7           5           1           0           0           2
Swap:             0           0           0


# 最后执行时间同步
[root@localhost ~]# yum install ntpdate -y
[root@localhost ~]# ntpdate time.windows.com

以k8s-master-01为例，在k8s-master-02、k8s-node-01、k8s-node-02也需要执行。

(2)、修改host文件

根据规划设置主机名分别修改每台服务器的hostname主机名称：

# 根据规划设置主机名【k8s-master-01 节点上操作】
hostnamectl set-hostname k8s-master-01

# 根据规划设置主机名【k8s-master-02 节点上操作】
hostnamectl set-hostname k8s-master-02

# 根据规划设置主机名【k8s-node-01 节点操作】
hostnamectl set-hostname k8s-node-01

# 根据规划设置主机名【k8s-node-02 节点操作】
hostnamectl set-hostname k8s-node-02

然后将上面的内容复制到host文件中，所有节点修改主机名和hosts文件，文件内容如下：

cat >> /etc/hosts << EOF
192.168.1.39 master.k8s.io k8s-vip
192.168.1.35 master01.k8s.io k8s-master-01
192.168.1.36 master02.k8s.io k8s-master-02
192.168.1.37 node01.k8s.io k8s-node-01
192.168.1.38 node02.k8s.io k8s-node-02
EOF

以k8s-master-01为例，在k8s-master-02、k8s-node-01、k8s-node-02也需要执行，注意主机名称不一样。

(3)、调整内核参数

将桥接的 IPV4 流量传递到 iptables 链。

cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

以k8s-master-01为例，在k8s-master-02、k8s-node-01、k8s-node-02也需要执行。

修改完成后，在所有节点执行sysctl --system加载参数使其生效：

(4)、所有节点安装Docker

所有节点安装 docker/kubelet/kubeadm/kubectl，Kubernetes 默认 CRI（容器运行时）为 docker，因此先安装 docker，以k8s-master-01为例，在k8s-master-02、k8s-node-01、k8s-node-02也需要执行。

(4-1)、配置 docker 的阿里 yum 源?

cat >/etc/yum.repos.d/docker.repo<<EOF
[docker-ce-edge]
name=Docker CE Edge - $basearch
baseurl=https://mirrors.aliyun.com/docker-ce/linux/centos/7/$basearch/edge
enabled=1
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/docker-ce/linux/centos/gpg
EOF

(4-2)、yum 安装 docker?

# yum 安装
yum -y install docker-ce

# 查看 docker 版本
docker --version

?(4-3)、配置 docker 的镜像源

cat >> /etc/docker/daemon.json << EOF
{
"registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
}
EOF

(4-4)、启动 docker?

systemctl start docker
systemctl enable docker
systemctl status docker

(5)、所有节点配置K8S源

执行下面的命令，定义kubernetes源：

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
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

以k8s-master-01为例，在k8s-master-02、k8s-node-01、k8s-node-02也需要执行：

(6)、所有节点安装kubeadm，kubelet和kubectl

由于版本更新频繁，这里指定版本号1.21.3部署。?

[root@localhost ~]# yum install -y kubelet-1.21.3 kubeadm-1.21.3 kubectl-1.21.3

以k8s-master-01为例，在k8s-master-02、k8s-node-01、k8s-node-02也需要执行：

这里根据网速快慢，可能需等待一些时间。

安装完毕之后，如下图。

k8s通过kubeadm安装出来以后都是以Pod方式存在，即底层是以容器方式运行，所以kubelet必须设置开机自启。

systemctl enable kubelet

(7)、所有master 节点安装keepalived

【k8s-master-01 + k8s-master-02上操作】

(7-1)、安装keepalived?

yum install -y keepalived

(7-2)、配置keepalived

keepalived中使用track_script机制来配置脚本进行探测kubernetes的master节点是否宕机，并以此切换节点实现高可用。

k8s-master-01节点的keepalived配置文件如下所示，配置文件所在的位/etc/keepalived/keepalived.cfg：

cat > /etc/keepalived/keepalived.conf <<EOF 
! Configuration File for keepalived

global_defs {
   router_id k8s
}

vrrp_script check_haproxy {
    script "killall -0 haproxy"
    interval 3
    weight -2
    fall 10
    rise 2
}

vrrp_instance VI_1 {
    state MASTER 
    interface ens33 
    mcast_src_ip 192.168.1.35
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass ceb1b3ec013d66163d6ab
    }
    virtual_ipaddress {
        192.168.1.39
    }
    track_script {
        check_haproxy
    }
}
EOF

需要注意几点：

mcast_src_ip：配置多播源地址，此地址是当前主机的 ip 地址。
priority：keepalived根据此项参数的大小仲裁master节点。我们这里让 master 节点为kubernetes提供服务，其他两个节点暂时为备用节点。因此k8s-master-01节点设置为100，k8s-master-02节点设置为99。
state：我们将k8s-master-01节点的state字段设置为MASTER，其他节点字段修改为BACKUP。

配置 k8s-master-02 节点，配置文件内容如下：

cat > /etc/keepalived/keepalived.conf <<EOF 
! Configuration File for keepalived

global_defs {
   router_id k8s
}

vrrp_script check_haproxy {
    script "killall -0 haproxy"
    interval 3
    weight -2
    fall 10
    rise 2
}

vrrp_instance VI_1 {
    state BACKUP 
    interface ens33 
    mcast_src_ip 192.168.1.36
    virtual_router_id 51
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass ceb1b3ec013d66163d6ab
    }
    virtual_ipaddress {
        192.168.1.39
    }
    track_script {
        check_haproxy
    }
}
EOF

(7-3)、启动、检查keepalived

【k8s-master-01 和 k8s-master-02 均要启动】?

# 设置开机启动
systemctl enable keepalived.service

# 启动keepalived
systemctl start keepalived.service

# 查看启动状态
systemctl status keepalived.service

启动成功后，我们通过下面的命令查看 master 网卡信息：

ip a s ens33

可以看到，当前虚拟IP（192.168.1.39）是飘移到了k8s-master-01这个节点。我们可以尝试停掉k8s-master-01的keepalived服务，查看vip是否能漂移到其他的master，并且重新启动k8s-master-01的keepalived服务，查看vip是否能正常漂移回来，证明配置没有问题。

(8)、所有master 节点安装haproxy

【k8s-master-01 + k8s-master-02上操作】

(8-1)、安装haproxy?

yum install -y haproxy

(8-2)、配置haproxy

所有master节点的haproxy配置相同，haproxy 的配置文件是/etc/haproxy/haproxy.cfg。

配置中声明了后端代理的两个 master 节点服务器，指定了 haproxy 运行的端口为 16443 等，因此 16443 端口为集群的入口。

cat > /etc/haproxy/haproxy.cfg << EOF
#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
    # to have these messages end up in /var/log/haproxy.log you will
    # need to:
    # 1) configure syslog to accept network log events.  This is done
    #    by adding the '-r' option to the SYSLOGD_OPTIONS in
    #    /etc/sysconfig/syslog
    # 2) configure local2 events to go to the /var/log/haproxy.log
    #   file. A line like the following can be added to
    #   /etc/sysconfig/syslog
    #
    #    local2.*                       /var/log/haproxy.log
    #
    log         127.0.0.1 local2
    
    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon 
       
    # turn on stats unix socket
    stats socket /var/lib/haproxy/stats
#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------  
defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000
#---------------------------------------------------------------------
# kubernetes apiserver frontend which proxys to the backends
#--------------------------------------------------------------------- 
frontend kubernetes-apiserver
    mode                 tcp
    bind                 *:16443
    option               tcplog
    default_backend      kubernetes-apiserver    
#---------------------------------------------------------------------
# round robin balancing between the various backends
#---------------------------------------------------------------------
backend kubernetes-apiserver
    mode        tcp
    balance     roundrobin
    server      k8s-master-01   192.168.1.35:6443 check
    server      k8s-master-02   192.168.1.36:6443 check
#---------------------------------------------------------------------
# collection haproxy statistics message
#---------------------------------------------------------------------
listen stats
    bind                 *:10080
    stats auth           admin:awesomePassword
    stats refresh        5s
    stats realm          HAProxy\ Statistics
    stats uri            /admin?stats
EOF

(8-3)、启动和检查haproxy

# 设置开机启动
systemctl enable haproxy

# 开启haproxy
systemctl start haproxy

# 查看启动状态
systemctl status haproxy

# 检查端口
netstat -lntup | grep haproxy

(9)、安装、初始化master

在具有vip的master上操作，这里为k8s-master-01这个节点。

(9-1)、创建kubeadm配置文件

[root@k8s-master-01]# vim kubeadm-config.yaml
apiServer:
  certSANs:
    - k8s-master-01
    - k8s-master-02
    - k8s-master-03
    - master.k8s.io
    - 192.168.1.35
    - 192.168.1.36
    - 192.168.1.39
    - 127.0.0.1
  extraArgs:
    authorization-mode: Node,RBAC
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: "master.k8s.io:16443"
controllerManager: {}
dns: 
  type: CoreDNS
etcd:
  local:    
    dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: v1.21.3
networking: 
  dnsDomain: cluster.local  
  podSubnet: 10.244.0.0/16
  serviceSubnet: 10.1.0.0/16
scheduler: {}

(9-2)、初始化master节点??

[root@k8s-master-01]# kubeadm init --config kubeadm-config.yaml

执行kubeadm init 初始化，中间会拉取镜像，速度较慢。执行完后，如下图，我们需要提前复制一下下图框起来的几个命令：

(9-3)、按照提示配置环境变量??

[root@k8s-master-01]# mkdir -p $HOME/.kube
[root@k8s-master-01]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@k8s-master-01]# sudo chown $(id -u):$(id -g) $HOME/.kube/config

(9-4)、查看集群状态?

[root@k8s-master-01 ~]# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS      MESSAGE                                                                                       ERROR
scheduler            Unhealthy   Get "http://127.0.0.1:10251/healthz": dial tcp 127.0.0.1:10251: connect: connection refused   
controller-manager   Unhealthy   Get "http://127.0.0.1:10252/healthz": dial tcp 127.0.0.1:10252: connect: connection refused   
etcd-0               Healthy     {"health":"true"}

可以看到，scheduler和controller-manager的状态都是Unhealthy，我们需要修改配置文件：

vim /etc/kubernetes/manifests/kube-scheduler.yaml

将- --port=0注释掉。

vim /etc/kubernetes/manifests/kube-controller-manager.yaml

将- --port=0注释掉。

修改完成后，继续查看master状态：?

[root@k8s-master-01 ~]# kubectl get cs
Warning: v1 ComponentStatus is deprecated in v1.19+
NAME                 STATUS    MESSAGE             ERROR
controller-manager   Healthy   ok                  
scheduler            Healthy   ok                  
etcd-0               Healthy   {"health":"true"}

可以看到，各个组件的状态都是Healthy健康状态。

查看集群pod：?

[root@k8s-master-01 ~]# kubectl get pods -n kube-system
NAME                                    READY   STATUS    RESTARTS   AGE
coredns-59d64cd4d4-jw4s4                0/1     Pending   0          10m
coredns-59d64cd4d4-zp7kk                0/1     Pending   0          10m
etcd-k8s-master-01                      1/1     Running   0          10m
kube-apiserver-k8s-master-01            1/1     Running   0          10m
kube-controller-manager-k8s-master-01   1/1     Running   0          65s
kube-proxy-d6vkg                        1/1     Running   0          10m
kube-scheduler-k8s-master-01            1/1     Running   0          85s

[root@k8s-master-01 ~]# kubectl get nodes -n kube-system
NAME            STATUS     ROLES                  AGE   VERSION
k8s-master-01   NotReady   control-plane,master   14m   v1.21.3

如上，集群默认也把coredns安装了，这里处于pending状态的原因是因为还没有安装集群网络组件。

(10)、安装集群网络组件

【 k8s-master-01上操作】

先从GitHub仓库下载kube-flannel.yml：?

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

国外站点下载很慢，经常连不上：

安装：?

kubectl apply -f http://120.78.77.38/file/kube-flannel.yaml

安装完CNI网络插件后，节点的状态就变成Ready了。我们使用查看pod状态，可以看到，状态都是Running运行状态。

[root@k8s-master-01 ~]# kubectl  get pod -n kube-system
NAME                                       READY   STATUS    RESTARTS   AGE
coredns-59d64cd4d4-jw4s4                   1/1     Running   0          24m
coredns-59d64cd4d4-zp7kk                   1/1     Running   0          24m
etcd-k8s-master-01                         1/1     Running   0          24m
kube-apiserver-k8s-master-01               1/1     Running   0          24m
kube-controller-manager-k8s-master-01      1/1     Running   0          14m
kube-flannel-ds-amd64-cf9k2                1/1     Running   0          8m
kube-proxy-d6vkg                           1/1     Running   0          24m
kube-scheduler-k8s-master-01               1/1     Running   0          15m


[root@k8s-master-01 ~]# kubectl  get node  -n kube-system
NAME            STATUS   ROLES                  AGE   VERSION
k8s-master-01   Ready    control-plane,master   24m   v1.21.3

?(11)、其他节点加入集群

【 k8s-master-02 + k8s-node-01 + k8s-node-02上操作】

(11-1)、k8s-master-02加入集群

(11-1-1)、复制密钥及相关文件

在第一次执行init的机器，此处为k8s-master-01上操作，复制文件到k8s-master-02。

ssh root@192.168.1.36 mkdir -p /etc/kubernetes/pki/etcd
scp /etc/kubernetes/admin.conf root@192.168.1.36:/etc/kubernetes
scp /etc/kubernetes/pki/{ca.*,sa.*,front-proxy-ca.*} root@192.168.1.36:/etc/kubernetes/pki
scp /etc/kubernetes/pki/etcd/ca.* root@192.168.1.36:/etc/kubernetes/pki/etcd

(11-1-2)、master加入集群

在k8s-master-02上操作，执行在k8s-master-01上init后输出的join命令：

kubeadm join master.k8s.io:16443 --token f8iwdm.1hhk6zo1onlre1qi \
        --discovery-token-ca-cert-hash sha256:57d56607b336b9ed62f07ac9eabdda5c90215b6cf251d2af3b98c82b1ea4fe66 \
        --control-plane

在k8s-master-02上执行join命令，需要带上参数--control-plane表示把master控制节点加入集群。

[root@k8s-master-02 /]# kubeadm join master.k8s.io:16443 --token f8iwdm.1hhk6zo1onlre1qi \
>         --discovery-token-ca-cert-hash sha256:57d56607b336b9ed62f07ac9eabdda5c90215b6cf251d2af3b98c82b1ea4fe66 \
>         --control-plane
[preflight] Running pre-flight checks
        [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[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'
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [k8s-master-01 k8s-master-02 k8s-master-03 kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local master.k8s.io] and IPs [10.1.0.1 192.168.1.36 192.168.1.35 192.168.1.39 127.0.0.1]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [k8s-master-02 localhost] and IPs [192.168.1.36 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [k8s-master-02 localhost] and IPs [192.168.1.36 127.0.0.1 ::1]
[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"
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Using existing kubeconfig file: "/etc/kubernetes/admin.conf"
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[endpoint] WARNING: port specified in controlPlaneEndpoint overrides bindPort in the controlplane address
[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] Checking that the etcd cluster is healthy
[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...
[etcd] Announced new etcd member joining to the existing etcd cluster
[etcd] Creating static Pod manifest for "etcd"
[etcd] Waiting for the new etcd member to join the cluster. This can take up to 40s
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[mark-control-plane] Marking the node k8s-master-02 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 k8s-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.
* A new etcd member was added to the local/stacked etcd cluster.

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.


[root@k8s-master-02 /]#  mkdir -p $HOME/.kube
[root@k8s-master-02 /]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@k8s-master-02 /]#  sudo chown $(id -u):$(id -g) $HOME/.kube/config

(11-1-3)、检查集群及pod状态

在其中一台master上执行命令检查集群及pod状态。

[root@k8s-master-02 /]# kubectl get node
NAME            STATUS   ROLES                  AGE   VERSION
k8s-master-01   Ready    control-plane,master   34m   v1.21.3
k8s-master-02   Ready    control-plane,master   84s   v1.21.3


[root@k8s-master-02 /]# kubectl get pods --all-namespaces
NAMESPACE     NAME                                       READY   STATUS    RESTARTS   AGE
kube-system   coredns-59d64cd4d4-jw4s4                   1/1     Running   0          34m
kube-system   coredns-59d64cd4d4-zp7kk                   1/1     Running   0          34m
kube-system   etcd-k8s-master-01                         1/1     Running   0          34m
kube-system   etcd-k8s-master-02                         1/1     Running   0          87s
kube-system   kube-apiserver-k8s-master-01               1/1     Running   0          34m
kube-system   kube-apiserver-k8s-master-02               1/1     Running   0          85s
kube-system   kube-controller-manager-k8s-master-01      1/1     Running   1          24m
kube-system   kube-controller-manager-k8s-master-02      1/1     Running   0          81s
kube-system   kube-flannel-ds-amd64-bm9gq                1/1     Running   0          93s
kube-system   kube-flannel-ds-amd64-cf9k2                1/1     Running   0          17m
kube-system   kube-proxy-d6vkg                           1/1     Running   0          34m
kube-system   kube-proxy-s548k                           1/1     Running   0          93s
kube-system   kube-scheduler-k8s-master-01               1/1     Running   1          24m
kube-system   kube-scheduler-k8s-master-02               1/1     Running   0          70s

如上，可以看到，当前集群中有两个node，并且状态都是Ready，并且pod状态也都是Running。

(11-2)、k8s-node-01、k8s-node-02 加入集群

(11-2-1)、node加入集群

在其他两台node节点上操作，执行join命令，在k8s-node-01和k8s-node-02上操作：?

?(11-2-2)、检查集群及pod状态

[root@k8s-master-02 /]# kubectl get node
NAME            STATUS   ROLES                  AGE     VERSION
k8s-master-01   Ready    control-plane,master   37m     v1.21.3
k8s-master-02   Ready    control-plane,master   4m58s   v1.21.3
k8s-node-01     Ready    <none>                 60s     v1.21.3
k8s-node-02     Ready    <none>                 56s     v1.21.3


[root@k8s-master-01 ~]# kubectl get pods -n kube-system
NAME                                       READY   STATUS    RESTARTS   AGE
coredns-59d64cd4d4-jw4s4                   1/1     Running   0          48m
coredns-59d64cd4d4-zp7kk                   1/1     Running   0          48m
etcd-k8s-master-01                         1/1     Running   0          48m
etcd-k8s-master-02                         1/1     Running   0          16m
kube-apiserver-k8s-master-01               1/1     Running   0          48m
kube-apiserver-k8s-master-02               1/1     Running   0          16m
kube-controller-manager-k8s-master-01      1/1     Running   1          39m
kube-controller-manager-k8s-master-02      1/1     Running   0          16m
kube-flannel-ds-amd64-bm9gq                1/1     Running   0          16m
kube-flannel-ds-amd64-cf9k2                1/1     Running   0          32m
kube-flannel-ds-amd64-vz5z9                1/1     Running   0          12m
kube-flannel-ds-amd64-xwpg2                1/1     Running   0          12m
kube-proxy-5kzr8                           1/1     Running   0          12m
kube-proxy-d6mfp                           1/1     Running   0          12m
kube-proxy-d6vkg                           1/1     Running   0          48m
kube-proxy-s548k                           1/1     Running   0          16m
kube-scheduler-k8s-master-01               1/1     Running   1          39m
kube-scheduler-k8s-master-02               1/1     Running   0          15m

如上，可以看到，当前集群中有四个node，并且状态都是Ready，并且pod状态也都是Running。

(12)、测试 kubernetes 集群

在 Kubernetes 集群中创建一个 pod，验证是否正常运行：?

# 创建 nginx deployment
[root@k8s-master-01 ~]# kubectl create deployment nginx --image=nginx
deployment.apps/nginx created


# 暴露端口
[root@k8s-master-01 ~]# kubectl expose deployment nginx --port=80 --type=NodePort
service/nginx exposed


# 查看状态
[root@k8s-master-01 ~]# kubectl get pod,svc
NAME                         READY   STATUS              RESTARTS   AGE
pod/nginx-6799fc88d8-56nsc   0/1     ContainerCreating   0          14s

NAME                 TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.1.0.1       <none>        443/TCP        41m
service/nginx        NodePort    10.1.196.129   <none>        80:30736/TCP   6s

我们看到，对外暴露的端口号是30736，我们可以使用任意一台节点的IP加上端口号，访问：

192.168.1.35:30736

192.168.1.36:30736

192.168.1.37:30736

192.168.1.38:30736

192.168.1.39:30736

接下来，我们尝试停掉k8s-master-01（这里我直接将这台虚拟机关了），测试一下集群是否正常提供服务：

可以看到，虚拟IP（192.168.1.39）已经漂移到k8s-master-02节点上。浏览器再次访问：http://192.168.1.36:30736/、http://192.168.1.37:30736/、http://192.168.1.38:30736/、http://192.168.1.39:30736/，也能正常访问到nginx。

文章来源:https://blog.csdn.net/Weixiaohuai/article/details/135478349
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