[系统运维]Docker系列文-----一台全新Linux系统简易搭建k8s集群全过程 建议收藏！！（6）

一.新建一台全新的机器

省略了前面Linux系统的安装过程

查看一下系统的版本：

[root@gogogo ~]# cat /etc/centos-release
CentOS Linux release 8.3.2011

二.关闭防火墙和Selinux等文件

[root@localhost ~]# hostnamectl set-hostname 'gogogo'
[root@gogogo ~]# vim /etc/selinux/config 
SELINUX=disabled
[root@gogogo ~]# setenforce 0
关闭防火墙
[root@gogogo ~]# systemctl stop firewalld
[root@gogogo ~]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

三.卸载旧版本的docker以及相关文件：

[root@gogogo ~]# yum remove docker \
>                   docker-client \
>                   docker-client-latest \
>                   docker-common \
>                   docker-latest \
>                   docker-latest-logrotate \
>                   docker-logrotate \
>                   docker-engine

四.安装yum-utils软件包并且配置aliyun的源

yum install -y yum-utils
yum-config-manager \
	    --add-repo \
	        http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

五.安装docker设置开机自启

yum install -y docker-ce docker-ce-cli containerd.io
[root@gogogo ~]# systemctl start docker
[root@gogogo ~]# systemctl enable docker
Created symlink /etc/systemd/system/multi-user.target.wants/docker.service → /usr/lib/systemd/system/docker.service.

六.配置Docker使用systemd作为默认Cgroup驱动

[root@gogogo ~]# cat <<EOF > /etc/docker/daemon.json
> {
>    "exec-opts": ["native.cgroupdriver=systemd"]
> }
> EOF

七.关闭swap分区（kubernetes关闭swap主要是为了性能考虑）

swapoff -a # 临时
[root@gogogo ~]# vi /etc/fstab
#/dev/mapper/cl-swap     none                    swap    defaults        0 0

八.安装Kubeadm、kubelet、kubectl：

kubeadm --》k8s的管理程序–》在master上运行的–》建立整个k8s集群
kubelet --》在node节点上用来管理容器的–》管理docker，告诉docker程序去启动容器
master和node通信用的–》管理docker，告诉docker程序去启动容器
一个在集群中每个节点（node）上运行的代理。 它保证容器（containers）都 运行在 Pod 中。
kubectl --》在master上用来给node节点发号施令的程序，用来控制node节点的，告诉它们做什么事情的，是命令行操作的工具

九.添加kubenetes YUM源

[root@gogogo ~]# 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

十.配置Kubernetes Master

直接初始化(kubeadm init)会报错
需要替换tag 为 阿里云的(init所要求的tag标签)

[root@gogogo ~]# docker pull  coredns/coredns:1.8.4
[root@gogogo ~]# docker tag coredns/coredns:1.8.4 registry.aliyuncs.com/google_containers/coredns:v1.8.4

十一.初始化（kubeadm init）

[root@gogogo ~]# kubeadm init \
> --apiserver-advertise-address=192.168.2.19 \
> --image-repository registry.aliyuncs.com/google_containers \
> --service-cidr=10.1.0.0/16 \
> --pod-network-cidr=10.244.0.0/16

192.168.2.19 是k8s Master的ip。
–service-cidr 是为服务VIP使用可选IP地址范围(默认值“10.96.0.0/12”）。
–pod-network-cidr string 指定pod网络的IP地址范围。如果设置，控制平面将自动为每个节点分配CIDR。

十二.按照输出提示 运行命令

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

kubeadm join 192.168.2.19:6443 --token q7swys.w4w2ivlmg2elcdnz \
	--discovery-token-ca-cert-hash sha256:27ea78090a55e95250af517ab33bbe863b5e84bc2fcc430897b8a25dd913ac6e 

执行：

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

使用下述命令可以将节点加入集群：

kubeadm join 192.168.2.19:6443 --token q7swys.w4w2ivlmg2elcdnz \
	--discovery-token-ca-cert-hash sha256:27ea78090a55e95250af517ab33bbe863b5e84bc2fcc430897b8a25dd913ac6e 

注意：token的有效时间是24小时，过期了需要使用下述命令重新获取

[root@manager149 docker]# kubeadm token create --print-join-command

十三.安装网络服务插件：（kube-flannel）

Flannel是CoreOS团队针对Kubernetes设计的一个网络服务，它的功能是让集群中的不同节点创建的Docker容器都具有全集群唯一的虚拟IP地址，Flannel的设计目的就是为集群中的所有节点重新规划IP地址，从而使得不同节点上的容器能够获得“同属一个内网”且”不重复的”IP地址，并让属于不同节点上的容器能够直接通过内网IP通信，Flannel实质上是一种“覆盖网络(overlaynetwork)”，也就是将TCP数据包装在另一种网络包里面进行路由转发和通信，目前已经支持udp、vxlan、host-gw、aws-vpc、gce路由等数据转发方式。

[root@gogogo ~]# vi kube-flannel.yml

[root@gogogo ~]# cat kube-flannel.yml 
---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
  name: psp.flannel.unprivileged
  annotations:
    seccomp.security.alpha.kubernetes.io/allowedProfileNames: docker/default
    seccomp.security.alpha.kubernetes.io/defaultProfileName: docker/default
    apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
    apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default
spec:
  privileged: false
  volumes:
  - configMap
  - secret
  - emptyDir
  - hostPath
  allowedHostPaths:
  - pathPrefix: "/etc/cni/net.d"
  - pathPrefix: "/etc/kube-flannel"
  - pathPrefix: "/run/flannel"
  readOnlyRootFilesystem: false
  # Users and groups
  runAsUser:
    rule: RunAsAny
  supplementalGroups:
    rule: RunAsAny
  fsGroup:
    rule: RunAsAny
  # Privilege Escalation
  allowPrivilegeEscalation: false
  defaultAllowPrivilegeEscalation: false
  # Capabilities
  allowedCapabilities: ['NET_ADMIN', 'NET_RAW']
  defaultAddCapabilities: []
  requiredDropCapabilities: []
  # Host namespaces
  hostPID: false
  hostIPC: false
  hostNetwork: true
  hostPorts:
  - min: 0
    max: 65535
  # SELinux
  seLinux:
    # SELinux is unused in CaaSP
    rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: flannel
rules:
- apiGroups: ['extensions']
  resources: ['podsecuritypolicies']
  verbs: ['use']
  resourceNames: ['psp.flannel.unprivileged']
- apiGroups:
  - ""
  resources:
  - pods
  verbs:
  - get
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - nodes/status
  verbs:
  - patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: flannel
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: flannel
subjects:
- kind: ServiceAccount
  name: flannel
  namespace: kube-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: flannel
  namespace: kube-system
---
kind: ConfigMap
apiVersion: v1
metadata:
  name: kube-flannel-cfg
  namespace: kube-system
  labels:
    tier: node
    app: flannel
data:
  cni-conf.json: |
    {
      "name": "cbr0",
      "cniVersion": "0.3.1",
      "plugins": [
        {
          "type": "flannel",
          "delegate": {
            "hairpinMode": true,
            "isDefaultGateway": true
          }
        },
        {
          "type": "portmap",
          "capabilities": {
            "portMappings": true
          }
        }
      ]
    }
  net-conf.json: |
    {
      "Network": "10.244.0.0/16",
      "Backend": {
        "Type": "vxlan"
      }
    }
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: kube-flannel-ds
  namespace: kube-system
  labels:
    tier: node
    app: flannel
spec:
  selector:
    matchLabels:
      app: flannel
  template:
    metadata:
      labels:
        tier: node
        app: flannel
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: kubernetes.io/os
                operator: In
                values:
                - linux
      hostNetwork: true
      priorityClassName: system-node-critical
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: quay.io/coreos/flannel:v0.13.1-rc2
        command:
        - cp
        args:
        - -f
        - /etc/kube-flannel/cni-conf.json
        - /etc/cni/net.d/10-flannel.conflist
        volumeMounts:
        - name: cni
          mountPath: /etc/cni/net.d
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      containers:
      - name: kube-flannel
        image: quay.io/coreos/flannel:v0.13.1-rc2
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            cpu: "100m"
            memory: "50Mi"
          limits:
            cpu: "100m"
            memory: "50Mi"
        securityContext:
          privileged: false
          capabilities:
            add: ["NET_ADMIN", "NET_RAW"]
        env:
        - name: POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name
        - name: POD_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
      volumes:
      - name: run
        hostPath:
          path: /run/flannel
      - name: cni
        hostPath:
          path: /etc/cni/net.d
      - name: flannel-cfg
        configMap:
          name: kube-flannel-cfg

十四.部署flannel服务

[root@gogogo ~]# kubectl apply -f kube-flannel.yml 
Warning: policy/v1beta1 PodSecurityPolicy is deprecated in v1.21+, unavailable in v1.25+
podsecuritypolicy.policy/psp.flannel.unprivileged created
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds created

十五.查看状态

[root@gogogo ~]# docker ps |grep flan
0be911fe55b2   dee1cac4dd20                                        "/opt/bin/flanneld -…"   About a minute ago   Up About a minute             k8s_kube-flannel_kube-flannel-ds-s8hlp_kube-system_256a607c-b60c-4982-ab49-5140c7c5c509_0
358ad86ca882   registry.aliyuncs.com/google_containers/pause:3.5   "/pause"                 5 minutes ago        Up 5 minutes                  k8s_POD_kube-flannel-ds-s8hlp_kube-system_256a607c-b60c-4982-ab49-5140c7c5c509_0
[root@gogogo ~]# ps aux|grep flan
root       21795  0.1  1.9 1265920 36104 ?       Ssl  16:17   0:00 /opt/bin/flanneld --ip-masq --kube-subnet-mgr
root       22892  0.0  0.0  12324  1112 pts/0    S+   16:18   0:00 grep --color=auto flan

flannel网络组件一安装好，状态就变成ready了

[root@gogogo ~]# kubectl get nodes
NAME     STATUS   ROLES                  AGE   VERSION
gogogo   Ready    control-plane,master   14m   v1.22.1

十六.关于节点

1. 下载 coredns 镜像 docker pull coredns/coredns:1.8.4
2. 安装kubeadm,kubelet和kubectl yum install -y kubelet kubeadm kubectl
3. 关闭交换分区 swapoff -a /vi /etc/fstab 注释掉最后一行
4. kubeadm join 192.168.2.19:6443 --token q7swys.w4w2ivlmg2elcdnz \ –
   discovery-token-ca-cert-hash sha256:27ea78090a55e95250af517ab33bbe863b5e84bc2fcc430897b8a25dd913ac6e

注意：手动启动kubelet后 不能再join了 join会报错
所以节点必须 直接join 自动去启动kubelet 不要手动启动kubelet

十七.测试

创建一个nginx的pod

[root@gogogo ~]# kubectl run sc-nginx --image=nginx --port=8080
pod/sc-nginx created

刚开始容器需要创建，等待2-3m即可创建好

[root@manager149 docker]# kubectl get pod
NAME       READY   STATUS              RESTARTS   AGE
sc-nginx   0/1     ContainerCreating   0          6s

[root@manager149 docker]# kubectl get pod
NAME       READY   STATUS    RESTARTS   AGE
sc-nginx   1/1     Running   0          120m

这时候我们一个简单的k8s集群就搭建成功了