K8s(Kubernetes)学习（二）：k8s集群搭建

k8s集群搭建

• minikube
  只是一个 K8S 集群模拟器，只有一个节点的集群，只为测试用，master 和 worker 都在一起。
• 裸机安装
  至少需要两台机器（主节点、工作节点个一台），需要自己安装 Kubernetes 组件，配置会稍微麻烦点。
  缺点：配置麻烦，缺少生态支持，例如负载均衡器、云存储。
• 直接用云平台 Kubernetes
  可视化搭建，只需简单几步就可以创建好一个集群。
  优点：安装简单，生态齐全，负载均衡器、存储等都给你配套好，简单操作就搞定
  腾讯云平台容器服务链接：https://cloud.tencent.com/act/cps/redirect?redirect=10058&cps_key=114d98136b019ef3d1d919d8ecadb3b7
• k3s
  安装简单，脚本自动完成。
  优点：轻量级，配置要求低，安装简单，生态齐全。
  链接：https://k3s.io/

法一：1 minikube

可直接利用Docker Desktop搭建

法二：2 裸机安装

0 环境准备

• 节点数量: 3 台虚拟机 centos7
• 硬件配置: 2G或更多的RAM，2个CPU或更多的CPU，硬盘至少30G 以上
• 网络要求: 多个节点之间网络互通，每个节点能访问外网

1 集群规划

• k8s-node1：10.15.0.5
• k8s-node2：10.15.0.6
• k8s-node3：10.15.0.7

2 设置主机名

$ hostnamectl set-hostname k8s-node1  
$ hostnamectl set-hostname k8s-node2
$ hostnamectl set-hostname k8s-node3

3 同步 hosts 文件

如果 DNS 不支持主机名称解析，还需要在每台机器的 /etc/hosts 文件中添加主机名和 IP 的对应关系：

cat >> /etc/hosts <<EOF
10.15.0.5 k8s-node1
10.15.0.6 k8s-node2
10.15.0.7 k8s-node3
EOF

4 关闭防火墙

$ systemctl stop firewalld && systemctl disable firewalld

5 关闭 SELINUX

注意: ARM 架构请勿执行,执行会出现 ip 无法获取问题!

$ setenforce 0 && sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config

6 关闭 swap 分区

$ swapoff -a && sed -ri 's/.*swap.*/#&/' /etc/fstab

7 同步时间

$ yum install ntpdate -y
$ ntpdate time.windows.com

8 安装 containerd

# 安装 yum-config-manager 相关依赖
$ yum install -y yum-utils device-mapper-persistent-data lvm2
# 添加 containerd yum 源
$ yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
# 安装 containerd
$ yum install  -y containerd.io cri-tools  
# 配置 containerd
$ cat >  /etc/containerd/config.toml <<EOF
disabled_plugins = ["restart"]
[plugins.linux]
shim_debug = true
[plugins.cri.registry.mirrors."docker.io"]
endpoint = ["https://frz7i079.mirror.aliyuncs.com"]
[plugins.cri]
sandbox_image = "registry.aliyuncs.com/google_containers/pause:3.2"
EOF
# 启动 containerd 服务 并 开机配置自启动
$ systemctl enable containerd && systemctl start containerd && systemctl status containerd 

# 配置 containerd 配置
$ cat > /etc/modules-load.d/containerd.conf <<EOF
overlay
br_netfilter
EOF

# 配置 k8s 网络配置
$ cat  > /etc/sysctl.d/k8s.conf <<EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF

# 加载 overlay br_netfilter 模块
$ modprobe overlay
$ modprobe br_netfilter

# 查看当前配置是否生效
$ sysctl -p /etc/sysctl.d/k8s.conf

9 添加源

• 查看源

$ yum repolist

• 添加源 x86

$ cat <<EOF > kubernetes.repo
[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
$ mv kubernetes.repo /etc/yum.repos.d/

• 添加源 ARM

$ cat << EOF > kubernetes.repo 
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-aarch64
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

$ mv kubernetes.repo /etc/yum.repos.d/

11 安装 k8s

# 安装最新版本
$ yum install -y kubelet kubeadm kubectl

# 指定版本安装
# yum install -y kubelet-1.26.0 kubectl-1.26.0 kubeadm-1.26.0

# 启动 kubelet
$ sudo systemctl enable kubelet && sudo systemctl start kubelet && sudo systemctl status kubelet

12 初始化集群

• 注意: 初始化 k8s 集群仅仅需要再在 master 节点进行集群初始化!

$ kubeadm init \
--apiserver-advertise-address=10.15.0.5 \
--pod-network-cidr=10.244.0.0/16 \
--image-repository registry.aliyuncs.com/google_containers \
--cri-socket=unix:///var/run/containerd/containerd.sock

# 添加新节点
$ kubeadm token create --print-join-command --ttl=0
$ kubeadm join 10.15.0.21:6443 --token xjm7ts.gu3ojvta6se26q8i --discovery-token-ca-cert-hash sha256:14c8ac5c04ff9dda389e7c6c505728ac1293c6aed5978c3ea9c6953d4a79ed34 

13 配置集群网络

创建配置: kube-flannel.yml ,执行 kubectl apply -f kube-flannel.yml

• 注意: 只在主节点执行即可!

---
kind: Namespace
apiVersion: v1
metadata:
  name: kube-flannel
  labels:
    pod-security.kubernetes.io/enforce: privileged
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: flannel
rules:
- apiGroups:
  - ""
  resources:
  - pods
  verbs:
  - get
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - get
  - 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-flannel
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: flannel
  namespace: kube-flannel
---
kind: ConfigMap
apiVersion: v1
metadata:
  name: kube-flannel-cfg
  namespace: kube-flannel
  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-flannel
  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-plugin
       #image: flannelcni/flannel-cni-plugin:v1.1.0 for ppc64le and mips64le (dockerhub limitations may apply)
        image: docker.io/rancher/mirrored-flannelcni-flannel-cni-plugin:v1.1.0
        command:
        - cp
        args:
        - -f
        - /flannel
        - /opt/cni/bin/flannel
        volumeMounts:
        - name: cni-plugin
          mountPath: /opt/cni/bin
      - name: install-cni
       #image: flannelcni/flannel:v0.20.2 for ppc64le and mips64le (dockerhub limitations may apply)
        image: docker.io/rancher/mirrored-flannelcni-flannel:v0.20.2
        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: flannelcni/flannel:v0.20.2 for ppc64le and mips64le (dockerhub limitations may apply)
        image: docker.io/rancher/mirrored-flannelcni-flannel:v0.20.2
        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
        - name: EVENT_QUEUE_DEPTH
          value: "5000"
        volumeMounts:
        - name: run
          mountPath: /run/flannel
        - name: flannel-cfg
          mountPath: /etc/kube-flannel/
        - name: xtables-lock
          mountPath: /run/xtables.lock
      volumes:
      - name: run
        hostPath:
          path: /run/flannel
      - name: cni-plugin
        hostPath:
          path: /opt/cni/bin
      - name: cni
        hostPath:
          path: /etc/cni/net.d
      - name: flannel-cfg
        configMap:
          name: kube-flannel-cfg
      - name: xtables-lock
        hostPath:
          path: /run/xtables.lock
          type: FileOrCreate

14 查看集群状态

# 查看集群节点状态 全部为 Ready 代表集群搭建成功
$ kubectl get nodes
NAME        STATUS   ROLES           AGE   VERSION
k8s-node1   Ready    control-plane   21h   v1.26.0
k8s-node2   Ready    <none>          21h   v1.26.0
k8s-node3   Ready    <none>          21h   v1.26.0

# 查看集群系统 pod 运行情况,下面所有 pod 状态为 Running 代表集群可用
$ kubectl get pod -A
NAMESPACE      NAME                                READY   STATUS    RESTARTS   AGE
default        nginx                               1/1     Running   0          21h
kube-flannel   kube-flannel-ds-gtq49               1/1     Running   0          21h
kube-flannel   kube-flannel-ds-qpdl6               1/1     Running   0          21h
kube-flannel   kube-flannel-ds-ttxjb               1/1     Running   0          21h
kube-system    coredns-5bbd96d687-p7q2x            1/1     Running   0          21h
kube-system    coredns-5bbd96d687-rzcnz            1/1     Running   0          21h
kube-system    etcd-k8s-node1                      1/1     Running   0          21h
kube-system    kube-apiserver-k8s-node1            1/1     Running   0          21h
kube-system    kube-controller-manager-k8s-node1   1/1     Running   0          21h
kube-system    kube-proxy-mtsbp                    1/1     Running   0          21h
kube-system    kube-proxy-v2jfs                    1/1     Running   0          21h
kube-system    kube-proxy-x6vhn                    1/1     Running   0          21h
kube-system    kube-scheduler-k8s-node1            1/1     Running   0          21h

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