K8S集群搭建-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_32318629/article/details/132375828

1 规划

节点名称	IP	备注
k8s-master	192.168.0.156	master
k8s-node1	192.168.0.70	node1
k8s-node2	192.168.0.167	node2

2 环境初始化

#修改节点名

hostnamectl set-hostname k8s-master
hostnamectl set-hostname k8s-node01
hostnamectl set-hostname k8s-node02

#关闭防火墙和selinux

systemctl stop firewalld
systemctl disable firewalld
sed -i 's/enforcing/disabled/' /etc/selinux/config
setenforce 0

#关闭swap分区

swapoff -a    # 临时关闭
vim /etc/fstab # 注释到swap那一行  永久关闭

#添加主机名与IP对应关系(三台主机都执行)

echo '''
192.168.0.156 k8s-master
192.168.0.70 k8s-node01
192.168.0.167 k8s-node02
''' >> /etc/hosts

#将桥接的IPv4流量传递到iptables的链(三台主机都执行)：

cat > /etc/sysctl.d/k8s.conf << EOF
net.ipv4.ip_forward = 1
net.ipv4.tcp_tw_recycle = 0
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

sysctl --system

#linux内核升级

#查看当前内核版本

uname -a

#安装epel源

rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
yum install -y https://www.elrepo.org/elrepo-release-7.el7.elrepo.noarch.rpm

#查看内核版本并安装最新版本

yum --disablerepo="*" --enablerepo="elrepo-kernel" list available

#安装最新lt内核版本

yum --disablerepo='*' --enablerepo=elrepo-kernel install kernel-lt -y

#查看系统grub内核的启动列表，这里编号0的5.4.252的lt版本是我们新安装的

awk -F\' '$1=="menuentry " {print i++ " : " $2}' /etc/grub2.cfg

在这里插入图片描述

#指定以新安装的编号0的内核版本为默认启动内核

grub2-set-default 0

#卸载旧内核版本

yum remove kernel -y

#重启机器，以新内核版本加载启动

reboot

#查看内核版本

在这里插入图片描述

3 K8S安装

3.1 安装docker

#依赖安装：

yum install -y yum-utils device-mapper-persistent-data lvm2

#docker源安装

yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

#docker安装

yum install -y docker-ce-18.09.0 docker-ce-cli-18.09.0 containerd.io

#启动并加入开机自启

systemctl start docker
systemctl enable docker

#Docker配置修改，设置cgroup驱动，这里用systemd

#配置修改为如下

vim /etc/docker/daemon.json

{
  "graph": "/data/docker",
  "registry-mirrors": ["https://01xxgaft.mirror.aliyuncs.com"],
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2"
}

#重启docker

systemctl restart docker

3.2 安装kubeadm，kubelet和kubectl

#添加k8s阿里云YUM软件源

#所有终端执行

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

#安装kubeadm，kubelet和kubectl

#所有机器执行

setenforce 0
yum install -y kubelet-1.16.2 kubeadm-1.16.2 kubectl-1.16.2
systemctl start kubelet
systemctl enable kubelet

#部署k8s的master和node节点

#部署master节点，在 192.168.0.156执行

#初始化master节点

kubeadm init   --apiserver-advertise-address=192.168.0.156 --image-repository registry.aliyuncs.com/google_containers   --kubernetes-version v1.16.0   --service-cidr=10.140.0.0/16 --pod-network-cidr=10.240.0.0/16

#网段问题，两个网段不要重，后面是/16，不要与当前机器网段一样

#这里执行完会生成一串命令用于node节点的加入，记录下来，接着执行以下命令

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

#部署node节点，在 192.168.0.70和 192.168.0.167执行

#这里复制上面生成的一串命令，我这里只是示例，命令根据你实际生成的复制去node节点执行

kubeadm join 192.168.0.156:6443 --token 8ubdw9.63z7bsd97rfblb6z \
    --discovery-token-ca-cert-hash sha256:c9abd2d72b082d39464546c246b72078c3d15f14e9972527c87514fba20670e6

3.3 安装网络插件（CNI）

#下面两种插件二选一，master上执行，如果是云服务器建议按照flannel，calico可能会和云网络环境有冲突

#安装flannel插件（轻量级用于快速搭建使用，初学推荐）

#创建配置文件命名为kube-flannel.yml

vi kube-flannel.yml

#修改net-conf.json下面的网段为上面init pod-network-cidr的网段地址（必须正确否则会导致集群网络问题）

net-conf.json: |
    {
      "Network": "10.240.0.0/16",
      "Backend": {
        "Type": "vxlan"
      }
    }

#全部配置如下

---
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": "10.240.0.0/16",
      "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-plugin
        image: rancher/mirrored-flannelcni-flannel-cni-plugin:v1.0.0
        command:
        - cp
        args:
        - -f
        - /flannel
        - /opt/cni/bin/flannel
        volumeMounts:
        - name: cni-plugin
          mountPath: /opt/cni/bin
      - name: install-cni
        image: quay.io/coreos/flannel:v0.15.1
        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:v0.15.1
        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-plugin
        hostPath:
          path: /opt/cni/bin
      - name: cni
        hostPath:
          path: /etc/cni/net.d
      - name: flannel-cfg
        configMap:
          name: kube-flannel-cfg

修改完安装插件，执行

kubectl apply -f kube-flannel.yml
kubectl get pods -n kube-system

4 测试k8s集群

#在Kubernetes集群中创建一个pod，验证是否正常运行

#创建一个pod，开放对外端口访问，这里会随机映射一个端口使用ipvs替代iptables

kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --type=NodePort

#查看pod状态，必须是running状态而且ready是1，并查看nginx svc的80端口映射到了哪个端口

kubectl get pod,svc

#访问任意机器的刚刚查看的映射端口，看看是否nginx已经运行

5 使用ipvs替代iptables

#在Kubernetes中Service有两种带来模型，一种是基于iptables的，一种是基于ipvs的两者比较的话，ipvs的性能明显要高一些，但是如果要使用它，需要手动载入ipvs模块

# 1.安装ipset和ipvsadm
yum install ipset ipvsadm  -y
# 2.添加需要加载的模块写入脚本文件
cat <<EOF> /etc/sysconfig/modules/ipvs.modules
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack
EOF
# 3.为脚本添加执行权限
chmod +x /etc/sysconfig/modules/ipvs.modules
# 4.执行脚本文件
/bin/bash /etc/sysconfig/modules/ipvs.modules
# 5.查看对应的模块是否加载成功
lsmod | grep -e -ip_vs -e nf_conntrack

#编辑/etc/sysconfig/kubelet

# 4、配置kubelet的cgroup
#编辑/etc/sysconfig/kubelet
vim /etc/sysconfig/kubelet
#添加下面的配置
KUBELET_CGROUP_ARGS="--cgroup-driver=systemd"
KUBE_PROXY_MODE="ipvs"
# 5、重启并设置kubelet开机自启
systemctl restart kubelet
systemctl enable kubelet

#查看、修改configMap配置文件

#查看proxy现有运行模式（默认为iptables）
kubectl get pod -n kube-system
kubectl logs kube-proxy-xxxx -n kube-system
#修改configMap配置
kubectl edit configMap kube-proxy -n kube-system
#输入/mode回车查找mode位置，按i进入编辑状态，将其中 mode="" 修改为 mode="ipvs"

#删除原pod，kubernetes会根据configMap配置文件自动重启proxy

kubectl get pod -n kube-system | grep proxy | awk '{system("kubectl delete pod "$1" -n kube-system")}'

#查验当前proxy的运行模式是否更改成功

kubectl get pod -n kube-system | grep proxy
kubectl logs kube-proxy-xxxx -n kube-system

查看当前配置的虚拟服务列表

ipvsadm -Ln

6 参考博客

https://blog.youkuaiyun.com/qq_40954652/article/details/123208590

https://blog.youkuaiyun.com/weixin_43950568/article/details/121852070

https://blog.youkuaiyun.com/Sy_spareribs/article/details/120179665

https://blog.youkuaiyun.com/weixin_45387943/article/details/123225090