STAy's Blog

落叶的一生，只为了归根么？

【k8s】k8s环境搭建

发布于 2021-07-18 | 分类于 k8s | 11分钟 | 1935字数

kubeadm是官方社区推出的一个用于快速部署kubernetes集群的工具。

这个工具能通过两条指令完成一个kubernetes集群的部署：

# 创建一个 Master 节点
kubeadm init

# 将一个 Node 节点加入到当前集群中
kubeadm join <Master节点的IP和端口 >

1. 安装要求

在开始之前，部署Kubernetes集群机器需要满足以下几个条件：

  • 一台或多台机器，操作系统 CentOS7.x-86_x64
  • 硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘30GB或更多
  • 可以访问外网，需要拉取镜像，如果服务器不能上网，需要提前下载镜像并导入节点
  • 禁止swap分区

2. 准备环境

角色 IP
master 10.0.0.200
node1 10.0.0.201
node2 10.0.0.202 
# 关闭防火墙
systemctl stop firewalld
systemctl disable firewalld

# 关闭selinux
sed -i 's/enforcing/disabled/' /etc/selinux/config  # 永久
setenforce 0  # 临时

# 关闭swap
swapoff -a  # 临时
sed -ri 's/.*swap.*/#&/' /etc/fstab    # 永久

# 根据规划设置主机名
# master
hostnamectl set-hostname master
# node1
hostnamectl set-hostname node1
# node2
hostnamectl set-hostname node2

# 在master添加hosts
cat >> /etc/hosts << EOF
10.0.0.200 master
10.0.0.201 node1
10.0.0.202 node2
EOF

# 将桥接的IPv4流量传递到iptables的链
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system  # 生效

# 时间同步
yum install ntpdate -y
ntpdate time.windows.com

3. 所有节点安装Docker/kubeadm/kubelet

Kubernetes默认CRI（容器运行时）为Docker，因此先安装Docker。

3.1 安装Docker

yum install -y wget
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo

yum -y install docker
systemctl enable docker && systemctl start docker

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

3.2 添加阿里云YUM软件源

$ 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

3.3 安装kubeadm，kubelet和kubectl

由于版本更新频繁，这里可以指定版本号部署：

# 指定版本号，若不指定为latest
# yum install -y kubelet-1.16.3 kubeadm-1.16.3 kubectl-1.16.3 

yum install -y kubelet kubeadm kubectl

systemctl enable kubelet && systemctl start kubelet

4. 部署Kubernetes Master

在Master执行。

kubeadm init --apiserver-advertise-address=10.0.0.200 --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.20.4 --service-cidr=10.96.0.0/12 --pod-network-cidr=10.244.0.0/16
  
  # --apiserver-advertise-address API服务器所公布的其正在监听的IP地址
  # --image-repository 选择用于拉取控制平面镜像的容器仓库，由于默认拉取镜像地址k8s.gcr.io国内无法访问，这里指定阿里云镜像仓库地址。
  # --kubernetes-version 如果上方安装kubelet没有指定版本号，这里也可不指定，需要注意不同版本之间的兼容，不兼容会有报错，指定兼容版本即可。
  # --service-cidr 为服务的虚拟 IP 地址另外指定 IP 地址段
  # --pod-network-cidr 指明 pod 网络可以使用的 IP 地址段。

如果提示找不到coredns:v1.8.0，就先在kubeadm init后加 --ignore-preflight-errors=all忽略报错。kubeadm init结束后，继续后面的步骤。

使用kubectl工具：

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

5. 加入Kubernetes Node

在Node执行。

向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：

$ kubeadm join 192.168.1.11:6443 --token esce21.q6hetwm8si29qxwn \
    --discovery-token-ca-cert-hash sha256:00603a05805807501d7181c3d60b478788408cfe6cedefedb1f97569708be9c5

默认token有效期为24小时，当过期之后，该token就不可用了。这时就需要重新创建token，操作如下：

kubeadm token create --print-join-command

6. 部署CNI网络插件

vi 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']
  defaultAddCapabilities: []
  requiredDropCapabilities: []
  # Host namespaces
  hostPID: false
  hostIPC: false
  hostNetwork: true
  hostPorts:
  - min: 0
    max: 65535
  # SELinux
  seLinux:
    # SELinux is unsed in CaaSP
    rule: 'RunAsAny'
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
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/v1beta1
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: |
    {
      "cniVersion": "0.2.0",
      "name": "cbr0",
      "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-amd64
  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: beta.kubernetes.io/os
                    operator: In
                    values:
                      - linux
                  - key: beta.kubernetes.io/arch
                    operator: In
                    values:
                      - amd64
      hostNetwork: true
      tolerations:
      - operator: Exists
        effect: NoSchedule
      serviceAccountName: flannel
      initContainers:
      - name: install-cni
        image: lizhenliang/flannel:v0.11.0-amd64 
        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: lizhenliang/flannel:v0.11.0-amd64 
        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"]
        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


kubectl apply -f kube-flannel.yml

kubectl get pods -n kube-system
NAME                             READY   STATUS    RESTARTS   AGE
coredns-7f89b7bc75-5bk98         1/1     Running   0          22m
coredns-7f89b7bc75-cz8vq         1/1     Running   0          22m
etcd-master                      1/1     Running   0          22m
kube-apiserver-master            1/1     Running   0          22m
kube-controller-manager-master   1/1     Running   0          22m
kube-flannel-ds-amd64-2cpdk      1/1     Running   0          7m3s
kube-flannel-ds-amd64-4xntj      1/1     Running   0          7m3s
kube-flannel-ds-amd64-khqfw      1/1     Running   0          7m3s
kube-proxy-7rc7h                 1/1     Running   0          22m
kube-proxy-fncg8                 1/1     Running   0          16m
kube-proxy-rd6kl                 1/1     Running   0          16m
kube-scheduler-master            1/1     Running   0          22m

kubectl get pod -n kube-system -o wide

在kubectl get pods -n kube-system，如果发现有ImagePullBackOff或者ErrImagePull，例如coredns-545d6fc579-4jw9w镜像是ImagePullBackOff状态，那么执行
kubectl get pods coredns-545d6fc579-4jw9w -n kube-system -o yaml | grep image:
查看没有拉去下来的镜像的全称，例如：
registry.aliyuncs.com/google_containers/coredns/coredns:v1.8.0无法下载下来，然后手动docker pull拉取下来(有时候只是镜像的命名问题而提示找不到镜像)：docker pull coredns/coredns:1.8.0，然后手动将拉去下来的镜像改以下tag:
sudo docker tag coredns/coredns:1.8.0 registry.aliyuncs.com/google_containers/coredns/coredns:v1.8.0

7. 测试kubernetes集群

在Kubernetes集群中创建一个pod，验证是否正常运行：

$ kubectl create deployment nginx --image=nginx
$ kubectl expose deployment nginx --port=80 --type=NodePort
$ kubectl get pod,svc

访问地址：http://NodeIP:Port

8. 安装dashboard

  1. 下载yaml
    wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.4/aio/deploy/recommended.yaml
    关于raw.githubusercontent.com failed: Connection

  2. 修改yaml

  3. 执行安装
    kubectl apply -f recommended.yaml

  4. 创建 serviceaccount
    kubectl create serviceaccount dashboard-admin -n kube-system

  5. 创建clusterrolebinding为dashboard sa授权集群权限cluster-admin
    kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin

  6. 查看dashboard所在node 可以用kubectl get pods -A -o wide ,然后找到dashboard 所在的node节点.

    使用token 登陆,获取token:kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')

关于dashboard的pod一直处于pending状态：

kubectl delete -f recommended.yaml

vi recommended.yaml

将所有
nodeSelector:
  "kubernetes.io/os": linux
注释掉

kubectl apply -f recommended.yaml

为匿名用户绑定管理员权限

kubectl create clusterrolebinding test:anonymous --clusterrole=cluster-admin --user=system:anonymous

# k8s
【k8s】卷 上一篇
【linux】/proc和/sys文件系统 下一篇
0%