备考CKA,kubernetes管理员第三天,搭建非高可用版的Kubernetes集群

文章目录

  • 搭建非高可用版kubernetes集群
    • 如需要一键安装Shell脚本前往如下链接
    • 集群信息
      • 1.节点信息
      • 2.组件版本
    • 安装前准备工作
      • 1.设置hosts解析
      • 2.调整系统配置
      • 3. 安装docker
    • 部署kubernetes
      • 1. 安装 kubeadm, kubelet 和 kubectl
      • 2. 初始化配置文件
      • 3. 提前下载镜像
      • 4. 初始化master节点
      • 5. 添加slave节点到集群中
      • 6. 安装flannel插件
      • 7. 设置master节点是否可调度(可选)
      • 8. 验证集群
      • 9. 部署dashboard
      • 10. 清理环境

搭建非高可用版kubernetes集群

如需要一键安装Shell脚本前往如下链接

https://blog.csdn.net/weixin_45724880/article/details/121247461

集群信息

1.节点信息

主机名 节点ip 角色 部署组件
k8s-master 172.16.3.57 master etcd, kube-apiserver, kube-controller-manager, kubectl, kubeadm, kubelet, kube-proxy, flannel
k8s-slave1 172.16.3.58 slave kubectl, kubelet, kube-proxy, flannel
k8s-slave2 172.21.32.9 slave kubectl, kubelet, kube-proxy, flannel

2.组件版本

组件 版本
centos 7.5及以上
Kernel Linux 3.10.0-1062.9.1.el7.x86_64
etcd 3.3.15
coredns\kubeadm\kubectl\kubelet\kube-proxy v1.16.2
flannel v0.11.0

安装前准备工作

1.设置hosts解析

修改hostname
hostname必须只能包含小写字母、数字、","、"-",且开头结尾必须是小写字母或数字

# 在master节点
$ hostnamectl set-hostname k8s-master #设置master节点的hostname

# 在slave-1节点
$ hostnamectl set-hostname k8s-slave1 #设置slave1节点的hostname

# 在slave-2节点
$ hostnamectl set-hostname k8s-slave2 #设置slave2节点的hostname

添加hosts解析
$ cat >>/etc/hosts< 172.16.3.58 k8s-master
172.21.3.57 k8s-slave1
172.21.3.60 k8s-slave2
EOF

2.调整系统配置

操作节点: 所有的master和slave节点(k8s-master,k8s-slave)需要执行

本章下述操作均以k8s-master为例,其他节点均是相同的操作(ip和hostname的值换成对应机器的真实值)

  • 设置安全组开放端口

如果节点间无安全组限制(内网机器间可以任意访问),可以忽略,否则,至少保证如下端口可通:
k8s-master节点:TCP:6443,2379,2380,60080,60081UDP协议端口全部打开
k8s-slave节点:UDP协议端口全部打开

  • 设置iptables
iptables -P FORWARD ACCEPT
  • 关闭swap
swapoff -a
# 防止开机自动挂载 swap 分区
sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
  • 关闭selinux和防火墙
sed -ri 's#(SELINUX=).*#\1disabled#' /etc/selinux/config
setenforce 0
systemctl disable firewalld && systemctl stop firewalld
  • 修改内核参数
cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward=1
vm.max_map_count=262144
EOF
modprobe br_netfilter
sysctl -p /etc/sysctl.d/k8s.conf
  • 设置yum源
$ curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
$ curl -o /etc/yum.repos.d/docker-ce.repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
$ cat < /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
        http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
$ yum clean all && yum makecache

3. 安装docker

操作节点: 所有节点

 ## 查看所有的可用版本
$ yum list docker-ce --showduplicates | sort -r
##安装旧版本 yum install docker-ce-cli-18.09.9-3.el7  docker-ce-18.09.9-3.el7
## 安装源里最新版本
$ yum install docker-ce

## 配置docker加速
$ mkdir -p /etc/docker
vi /etc/docker/daemon.json
{
  "insecure-registries": [    
    "172.21.32.15:5000" 
  ],                          
  "registry-mirrors" : [
    "https://8xpk5wnt.mirror.aliyuncs.com"
  ]
}
## 启动docker
$ systemctl enable docker && systemctl start docker

部署kubernetes

1. 安装 kubeadm, kubelet 和 kubectl

操作节点: 所有的master和slave节点(k8s-master,k8s-slave) 需要执行

$ yum install -y kubelet-1.16.0 kubeadm-1.16.0 kubectl-1.16.0
## 查看kubeadm 版本
$ kubeadm version
## 设置kubelet开机启动
$ systemctl enable kubelet 

2. 初始化配置文件

操作节点: 只在master节点(k8s-master)执行

#方法一:配置+初始化(推荐)
$ kubeadm init --apiserver-advertise-address=192.168.30.128 --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.18.0 --service-cidr=10.96.0.0/12 --pod-network-cidr=10.244.0.0/16

#方法二:flannel容易起不来
$ kubeadm config print init-defaults > kubeadm.yaml
$ cat kubeadm.yaml
apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: abcdef.0123456789abcdef
  ttl: 24h0m0s
  usages:
  - signing
  - authentication
kind: InitConfiguration
localAPIEndpoint:
  advertiseAddress: 172.21.32.15  # apiserver地址,因为单master,所以配置master的节点内网IP
  bindPort: 6443
nodeRegistration:
  criSocket: /var/run/dockershim.sock
  name: k8s-master
  taints:
  - effect: NoSchedule
    key: node-role.kubernetes.io/master
---
apiServer:
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns:
  type: CoreDNS
etcd:
  local:
    dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers  # 修改成阿里镜像源
kind: ClusterConfiguration
kubernetesVersion: v1.16.2
networking:
  dnsDomain: cluster.local
  podSubnet: 10.244.0.0/16  # Pod 网段,flannel插件需要使用这个网段
  serviceSubnet: 10.96.0.0/12
scheduler: {}

对于上面的资源清单的文档比较杂,要想完整了解上面的资源对象对应的属性,可以查看对应的 godoc 文档,地址: https://godoc.org/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta2。

3. 提前下载镜像

操作节点:只在master节点(k8s-master)执行

  # 查看需要使用的镜像列表,若无问题,将得到如下列表
$ kubeadm config images list --config kubeadm.yaml
registry.aliyuncs.com/google_containers/kube-apiserver:v1.16.0
registry.aliyuncs.com/google_containers/kube-controller-manager:v1.16.0
registry.aliyuncs.com/google_containers/kube-scheduler:v1.16.0
registry.aliyuncs.com/google_containers/kube-proxy:v1.16.0
registry.aliyuncs.com/google_containers/pause:3.1
registry.aliyuncs.com/google_containers/etcd:3.3.15-0
registry.aliyuncs.com/google_containers/coredns:1.6.2
  # 提前下载镜像到本地
$ kubeadm config images pull --config kubeadm.yaml
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-apiserver:v1.16.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-controller-manager:v1.16.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-scheduler:v1.16.0
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-proxy:v1.16.0
[config/images] Pulled registry.aliyuncs.com/google_containers/pause:3.1
[config/images] Pulled registry.aliyuncs.com/google_containers/etcd:3.3.15-0
[config/images] Pulled registry.aliyuncs.com/google_containers/coredns:1.6.2

重要更新:如果出现不可用的情况,请使用如下方式来代替:

  1. 还原kubeadm.yaml的imageRepository

    ...
    imageRepository: k8s.gcr.io
    ...
    
    ## 查看使用的镜像源
    kubeadm config images list --config kubeadm.yaml
    k8s.gcr.io/kube-apiserver:v1.16.0
    k8s.gcr.io/kube-controller-manager:v1.16.0
    k8s.gcr.io/kube-scheduler:v1.16.0
    k8s.gcr.io/kube-proxy:v1.16.0
    k8s.gcr.io/pause:3.1
    k8s.gcr.io/etcd:3.3.15-0
    k8s.gcr.io/coredns:1.6.2
    
  2. 使用docker hub中的镜像源来下载,注意上述列表中要加上处理器架构,通常我们使用的虚拟机都是amd64

    $ docker pull mirrorgooglecontainers/kube-scheduler-amd64:v1.16.0
    $ docker pull mirrorgooglecontainers/etcd-amd64:3.3.15-0
    ...
    $ docker tag mirrorgooglecontainers/etcd-amd64:3.3.15-0 k8s.gcr.io/etcd:3.3.15-0
    

4. 初始化master节点

操作节点:只在master节点(k8s-master)执行

kubeadm init --config kubeadm.yaml

若初始化成功后,最后会提示如下信息:

...
Your Kubernetes master 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

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 172.21.32.15:6443 --token abcdef.0123456789abcdef \
    --discovery-token-ca-cert-hash sha256:1c4305f032f4bf534f628c32f5039084f4b103c922ff71b12a5f0f98d1ca9a4f

接下来按照上述提示信息操作,配置kubectl客户端的认证

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

**⚠️注意:**此时使用 kubectl get nodes查看节点应该处于notReady状态,因为还未配置网络插件

若执行初始化过程中出错,根据错误信息调整后,执行kubeadm reset后再次执行init操作即可

5. 添加slave节点到集群中

操作节点:所有的slave节点(k8s-slave)需要执行
在每台slave节点,执行如下命令,该命令是在kubeadm init成功后提示信息中打印出来的,需要替换成实际init后打印出的命令。

kubeadm join 172.21.32.15:6443 --token abcdef.0123456789abcdef \
    --discovery-token-ca-cert-hash sha256:1c4305f032f4bf534f628c32f5039084f4b103c922ff71b12a5f0f98d1ca9a4f

6. 安装flannel插件

操作节点:只在master节点(k8s-master)执行

  • 下载flannel的yaml文件
#方法一:一键配置(推荐)
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
##由于我上面的kubeadm init xxx --pod-network-cidr就是10.244.0.0/16。所以此yaml文件就不需要更改了。

#方法二,需要配置yml文件
wget https://raw.githubusercontent.com/coreos/flannel/2140ac876ef134e0ed5af15c65e414cf26827915/Documentation/kube-flannel.yml
  • 修改配置,指定网卡名称,大概在文件的170行和190行,添加一行配置:
$ vi kube-flannel.yml
...      
      containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.11.0-amd64
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        - --iface=eth0  # 如果机器存在多网卡的话,指定内网网卡的名称,默认不指定的话会找第一块网
        resources:
          requests:
            cpu: "100m"
...
  • 执行安装flannel网络插件
# 先拉取镜像,此过程国内速度比较慢
$ docker pull quay.io/coreos/flannel:v0.11.0-amd64
# 执行flannel安装
$ kubectl create -f kube-flannel.yml

7. 设置master节点是否可调度(可选)

操作节点:k8s-master

默认部署成功后,master节点无法调度业务pod,如需设置master节点也可以参与pod的调度,需执行:

$ kubectl taint node k8s-master node-role.kubernetes.io/master:NoSchedule-

8. 验证集群

操作节点: 在master节点(k8s-master)执行

$ kubectl get nodes  #观察集群节点是否全部Ready
NAME                STATUS   ROLES    AGE   VERSION
k8s-master   Ready    master   22h   v1.13.3
k8s-slave   Ready    <none>   22h   v1.13.3

创建测试nginx服务

$ kubectl run  test-nginx --image=nginx:alpine

查看pod是否创建成功,并访问pod ip测试是否可用

$ kubectl get po -o wide
NAME                          READY   STATUS    RESTARTS   AGE   IP           NODE         NOMINATED NODE   READINESS GATES
test-nginx-5bd8859b98-5nnnw   1/1     Running   0          9s    10.244.1.2   k8s-slave1              
$ curl 10.244.1.2
...

Welcome to nginx!</h1>

If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p>

For online documentation and support please refer to "http://nginx.org/">nginx.org</a>./> Commercial support is available at "http://nginx.com/">nginx.com</a>.</p>

Thank you for using nginx.</em></p> </body> </html>

9. 部署dashboard

  • 部署服务
# 推荐使用下面这种方式
$ wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-beta5/aio/deploy/recommended.yaml
$ vi recommended.yaml
# 修改Service为NodePort类型
......
kind: Service
apiVersion: v1
metadata:
  labels:
    k8s-app: kubernetes-dashboard
  name: kubernetes-dashboard
  namespace: kubernetes-dashboard
spec:
  ports:
    - port: 443
      targetPort: 8443
  selector:
    k8s-app: kubernetes-dashboard
  type: NodePort  # 加上type=NodePort变成NodePort类型的服务
......
  • 查看访问地址,本例为30133端口
kubectl create -f recommended.yaml
kubectl -n kubernetes-dashboard get svc
NAME                        TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)         AGE
dashboard-metrics-scraper   ClusterIP   10.105.62.124           8000/TCP        31m
kubernetes-dashboard        NodePort    10.103.74.46            443:30133/TCP   31m 
  • 使用浏览器访问 https://62.234.133.177:30133,其中62.234.133.177为master节点的外网ip地址,chrome目前由于安全限制,测试访问不了,使用firefox可以进行访问。

  • 创建ServiceAccount进行访问

$ vi admin.conf
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: admin
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
roleRef:
  kind: ClusterRole
  name: cluster-admin
  apiGroup: rbac.authorization.k8s.io
subjects:
- kind: ServiceAccount
  name: admin
  namespace: kubernetes-dashboard

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin
  namespace: kubernetes-dashboard

$ kubectl create -f admin.conf
$ kubectl -n kubernetes-dashboard get secret |grep admin-token
admin-token-fqdpf                  kubernetes.io/service-account-token   3      7m17s
# 使用该命令拿到token,然后粘贴到
$ kubectl -n kubernetes-dashboard get secret admin-token-fqdpf -o jsonpath={.data.token}|base64 -d
eyJhbGciOiJSUzI1NiIsImtpZCI6Ik1rb2xHWHMwbWFPMjJaRzhleGRqaExnVi1BLVNRc2txaEhETmVpRzlDeDQifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlcm5ldGVzLWRhc2hib2FyZCIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJhZG1pbi10b2tlbi1mcWRwZiIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50Lm5hbWUiOiJhZG1pbiIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50LnVpZCI6IjYyNWMxNjJlLTQ1ZG...

10. 清理环境

如果你的集群安装过程中遇到了其他问题,我们可以使用下面的命令来进行重置:

$ kubeadm reset
$ ifconfig cni0 down && ip link delete cni0
$ ifconfig flannel.1 down && ip link delete flannel.1
$ rm -rf /var/lib/cni/

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