Kubernetes(k8s)centos7和8快速部署

Kubernetes快速部署

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:

-至少3台机器,操作系统 CentOS7+

  • 硬件配置:2GB或更多RAM,2个CPU或更多CPU,硬盘20GB或更多
  • 集群中所有机器之间网络互通
  • 可以访问外网,需要拉取镜像
  • 禁止swap分区

2. 学习目标

  1. 在所有节点上安装Docker和kubeadm
  2. 部署Kubernetes Master
  3. 部署容器网络插件
  4. 部署 Kubernetes Node,将节点加入Kubernetes集群中
  5. 部署Dashboard Web页面,可视化查看Kubernetes资源

3. 准备环境

img
ps:建议三台centos7,我用kubeletv1.23.1也做出来了。虽然kubeadm源是7,
也可以用三台centos8,kubeletv1.20.0稳定版(最新版可安装不一定能运行)
环境:三台centos7

角色 IP 配置
master 192.168.143.140 2G 4核
node1 192.168.143.141 3G 4核
node2 192.168.143.142 3G 4核
//给三台主机修改名字
[[email protected] ~]# hostname
master.example.com
[[email protected] ~]# hostname
node1.example.com
[[email protected] ~]# hostname
node2.example.com

//给三台主机关闭防火墙,selinux
systemctl disable  firewalld
sed -i 's/enforcing/disabled/' /etc/selinux/config  

//给三台主机关闭swap:
vim /etc/fstab
#/dev/mapper/centos-swap swap                    swap    defaults        0 0
注释掉swap分区


在master添加hosts:
[[email protected] ~]# vim /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
//后面添加此三行
192.168.143.140 master master.example.com
192.168.143.141 node1 node1.example.com
192.168.143.142 node2 node2.example.com


//将桥接的IPv4流量传递到iptables的链:
[[email protected] ~]# cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
//生效
[[email protected] ~]# sysctl --system
* Applying /usr/lib/sysctl.d/00-system.conf ...
* Applying /usr/lib/sysctl.d/10-default-yama-scope.conf ...
kernel.yama.ptrace_scope = 0
* Applying /usr/lib/sysctl.d/50-default.conf ...
kernel.sysrq = 16
kernel.core_uses_pid = 1
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.promote_secondaries = 1
net.ipv4.conf.all.promote_secondaries = 1
fs.protected_hardlinks = 1
fs.protected_symlinks = 1
* Applying /etc/sysctl.d/99-sysctl.conf ...
* Applying /etc/sysctl.d/k8s.conf ...
* Applying /etc/sysctl.conf ...

//给三台主机做时间同步:
yum -y install chrony
vim /etc/chrony.conf 
pool time1.aliyun.com iburst //时间同步删除原有的4条,修改为此行
systemctl enable  chronyd

//免密认证:
[[email protected] ~]# ssh-keygen -t rsa
[[email protected] ~]# ssh-copy-id master
[[email protected] ~]# ssh-copy-id node1
[[email protected] ~]# ssh-copy-id node2

//检查状态
[[email protected] ~]# for i in  node1 node2 master;do ssh [email protected]$i 'reboot';done
[[email protected] ~]# for i in master node1 node2;do ssh [email protected]$i 'getenforce';done
Disabled
Disabled
Disabled
[[email protected] ~]# for i in master node1 node2;do ssh [email protected]$i 'date';done
[[email protected] ~]# for i in master node1 node2;do ssh [email protected]$i 'free -h';done
              total        used        free      shared  buff/cache   available
Mem:           1.8G        105M        1.5G        9.6M        197M        1.5G
Swap:            0B          0B          0B
              total        used        free      shared  buff/cache   available
Mem:           2.8G        108M        2.5G        9.4M        194M        2.5G
Swap:            0B          0B          0B
              total        used        free      shared  buff/cache   available
Mem:           2.8G        111M        2.5G        9.4M        194M        2.5G
Swap:            0B          0B          0B


4. 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。

4.1 配置kubeadm源安装Docker

//给三台主机配置kubeadm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

//给三台主机做docker源
# wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
//建立缓存
# rm -rf /var/cache/yum/*
# yum makecache
//给三台主机配置docker-ce
# yum install -y docker-ce
# systemctl enable --now docker
# cat > /etc/docker/daemon.json << EOF
{
  "registry-mirrors": ["https://docker.mirrors.ustc.edu.cn/"],
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2"
}
EOF
# systemctl daemon-reload 
# systemctl restart docker
# docker info //查看有无配置

4.2 安装kubeadm,kubelet和kubectl

//不指定版本为最新版本,也可以使用
由于版本更新频繁,这里指定版本号部署:

//给三台主机做
# yum install -y kubelet-1.20.0 kubeadm-1.20.0 kubectl-1.20.0
# systemctl enable kubelet

5. 部署Kubernetes Master

在Master执行。

//注意 ip是master的 。version是kuber的版本。可以变
[[email protected] ~]# kubeadm init --apiserver-advertise-address 192.168.143.140 --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.20.0 --service-cidr=10.96.0.0/12 --pod-network-cidr=10.244.0.0/16
//存储信息。此行内容是。init完成后产生后,最后一行数据,添加集群时要用到。
[[email protected] ~]# vi init 
kubeadm join 192.168.143.140:6443 --token arkgcf.smaj7konv41yifxd 
    --discovery-token-ca-cert-hash sha256:30e1b03d7112abc8ed8b84bf0c69ef4bdb3498911ac468f3a2c7887bdd38918c  
[[email protected] ~]# echo 'export KUBECONFIG=/etc/kubernetes/admin.conf' > /etc/profile.d/k8s.sh
[[email protected] ~]# source /etc/profile.d/k8s.sh

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。

//普通用户要做的事,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


6. 安装Pod网络插件(CNI)

[[email protected] ~]# vim flannel.yaml 
---
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-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
[[email protected] ~]# kubectl apply -f flannel.yaml

确保能够访问到quay.io这个registery。

7. 加入Kubernetes Node

在node1 和node2执行。

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

kubeadm join 192.168.143.140:6443 --token arkgcf.smaj7konv41yifxd 
>     --discovery-token-ca-cert-hash sha256:30e1b03d7112abc8ed8b84bf0c69ef4bdb3498911ac468f3a2c7887bdd38918c

8. 测试kubernetes集群

在Kubernetes集群中创建一个pod,验证是否正常运行:

[[email protected] ~]# kubectl get nodes
NAME                 STATUS   ROLES                  AGE     VERSION
master.example.com   Ready    control-plane,master   21m     v1.20.0
node1.example.com    Ready    <none>                 5m44s   v1.20.0
node2.example.com    Ready    <none>                 5m39s   v1.20.0

[[email protected] ~]# kubectl create deployment nginx --image=nginx
deployment.apps/nginx created
[[email protected] ~]# kubectl expose deployment nginx --port=80 --type=NodePort
service/nginx exposed

//获取svc,pods的信息
[[email protected] ~]# kubectl get svc,pods
NAME                 TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP        28m
service/nginx        NodePort    10.109.147.208   <none>        80:32432/TCP   5m20s

NAME                         READY   STATUS    RESTARTS   AGE
pod/nginx-6799fc88d8-wk29t   1/1     Running   0          6m18s

//测试主机ip访问
[[email protected] ~]# curl 192.168.143.140:32432
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

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

<p><em>Thank you for using nginx.</em></p>
</body>
</html>
//建议使用server的ip来访问,因为不会改变
[[email protected] ~]# curl 10.109.147.208
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

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

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

访问地址:http://NodeIP:Port

本图文内容来源于网友网络收集整理提供,作为学习参考使用,版权属于原作者。
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