服务器环境配置

ip	描述	配置
192.168.43.201	master节点	CPU（2C） 内存（2G） 硬盘（50G）
192.168.43.202	node1节点	CPU（2C） 内存（2G） 硬盘（50G）
192.168.43.203	node2节点	CPU（2C） 内存（2G） 硬盘（50G）

三台服务器都要执行下面的操作

设置服务器主机名

#192.168.43.201服务器执行
hostnamectl set-hostname k8s-master
#192.168.43.202服务器执行
hostnamectl set-hostname k8s-node1
#192.168.43.203服务器执行
hostnamectl set-hostname k8s-node2

修改host文件解析域名

cat >> /etc/hosts << EOF
192.168.56.100  k8s-node1
192.168.56.101  k8s-node2
192.168.56.102  k8s-node3
EOF

时间同步

yum -y install ntp ntpdate

#时间服务器可以选择：ime.nist.gov、time.nuri.net、0.asia.pool.ntp.org、1.asia.pool.ntp.org、2.asia.pool.ntp.org、3.asia.pool.ntp.org中任意一个，只要保证可用就OK
tpdate 0.asia.pool.ntp.org

#将系统时间写入硬件时间
hwclock --systohc
timedatectl

禁用iptables和firewalld服务

kubernetes和docker在运行中会产生大量的iptables规则，为了不让系统规则跟它们混淆，直接关闭系统的规则

# 1 关闭firewalld服务
systemctl stop firewalld
systemctl disable firewalld
# 2 关闭iptables服务
systemctl stop iptables
systemctl disable iptables

禁用selinux

selinux是linux系统下的一个安全服务，如果不关闭它，在安装集群中会产生各种各样的奇葩问题

# 编辑 /etc/selinux/config 文件，修改SELINUX的值为disabled
# 注意修改完毕之后需要重启linux服务
SELINUX=disabled
# 永久关闭
sed -i 's/enforcing/disabled/' /etc/selinux/config 
 # 临时
setenforce 0

禁用swap分区

# vim /etc/fstab 分区配置文件，注释掉swap分区一行
# 注意修改完毕之后需要重启linux服务
 UUID=455cc753-7a60-4c17-a424-7741728c44a1 /boot    xfs     defaults        0 0
 /dev/mapper/centos-home /home                      xfs     defaults        0 0
# /dev/mapper/centos-swap swap                      swap    defaults        0 0

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

修改linux的内核参数

# 修改linux的内核参数，添加网桥过滤和地址转发功能
# 创建/etc/sysctl.d/kubernetes.conf文件，添加如下配置:
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1

# 重新加载配置
sysctl -p

# 加载网桥过滤模块
modprobe br_netfilter

# 查看网桥过滤模块是否加载成功
lsmod | grep br_netfilter

配置ipvs功能

# 1 安装ipset和ipvsadm
yum install ipset ipvsadmin -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_ipv4
EOF

# 3 为脚本文件添加执行权限
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_ipv4

重启服务器

reboot

安装Docker

安装最新版的docker即可，参考博客：Centos安装docker

集群搭建

安装kubeadm、kubelet和kubectl

三台服务器都要执行

1. 修改yum源为阿里源，提高下载速度

cat >/etc/yum.repos.d/kubernetes.repo <<EOF
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
       http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

2. 安装 kubeadm，kubelet和kubectl

yum install -y --setopt=obsoletes=0 kubeadm-1.17.17-0 kubelet-1.17.17-0 kubectl-1.17.17-0 

3. 修改kubelet配置

# 配置kubelet的cgroup
# vim /etc/sysconfig/kubelet，添加下面的配置
KUBELET_CGROUP_ARGS="--cgroup-driver=systemd"
KUBE_PROXY_MODE="ipvs"

# 4 设置kubelet开机自启
systemctl enable kubelet

下载docker镜像

kubeadmin方式安装的k8s运行在docker容器内，需要提前下载docker镜像，注意master节点和node节点的镜像不一样，要分开下载

1. master服务器执行下载镜像的脚本

#vim install.sh 新增如下配置
images=(
    kube-apiserver:v1.17.17
    kube-controller-manager:v1.17.17
    kube-scheduler:v1.17.17
    kube-proxy:v1.17.17
    pause:3.1
    etcd:3.4.3-0
    coredns:1.6.5
)

for imageName in ${images[@]} ; do
	docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
	docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName 	k8s.gcr.io/$imageName
	docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
done
#执行脚本进行安装
chmod +x install.sh
./install.sh

2. node节点下载镜像

#vim install.sh 新增如下配置
images=(
    kube-proxy:v1.17.17
    pause:3.1
)

for imageName in ${images[@]} ; do
	docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
	docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName 	k8s.gcr.io/$imageName
	docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/$imageName
done
#执行脚本进行安装
chmod +x install.sh
./install.sh

master服务器初始化

只需要在master服务器上执行

#初始化 注意最后面的ip为master主机的ip，需要修改服务器的实际ip
kubeadm init \
	--kubernetes-version=v1.17.17 \
    --pod-network-cidr=10.244.0.0/16 \
    --service-cidr=10.96.0.0/12 \
    --apiserver-advertise-address=192.168.43.201
# ===================输出信息========================
        Your Kubernetes control-plane has initialized successfully! # 控制面板就是master

        To start using your cluster, you need to run the following as a regular user:
        然后他告诉你如果想要使用集群，需要把配置文件放到家目录下
          mkdir -p $HOME/.kube
          sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
          sudo chown $(id -u):$(id -g) $HOME/.kube/config
        你可以使用k8s集群了  但是你应该安装网络插件
        You should now deploy a pod network to the cluster.
        Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
          https://kubernetes.io/docs/concepts/cluster-administration/addons/

        Then you can join any number of worker nodes by running the following on each as root:
        # 如果你想要添加工作结点，可以在node结点上以root身份执行下面的话
        kubeadm join 192.168.56.100:6443 --token 15ckqi.et50udit3pqdn180 \
            --discovery-token-ca-cert-hash 		
            sha256:a23f2c32749a128d653712e33c4045e5932339ddd96e61251348b203cfdba4bb
# ===================根据输出信息做一些操作========================
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config    

node节点加入master

node服务器执行命令加入master节点

# 将node节点加入集群 # 自己输入自己命令行输出的，不要全部复制
kubeadm join 192.168.56.100:6443 --token 8507uc.o0knircuri8etnw2 --discovery-token-ca-cert-hash  sha256:acc37967fb5b0acf39d7598f8a439cc7dc88f439a3f4d0c9cae88e7901b9d3f

token过期或忘记了可以在master节点重新生成token

kubeadm token create --print-join-command

master节点安装网络插件

master节点查看集群状态 ，状态均为NotReady，因为还没有配置网络插件

[root@master ~]# kubectl get nodes
NAME     STATUS     ROLES    AGE     VERSION
master   NotReady   master   6m43s   v1.17.4
node1    NotReady   <none>   22s     v1.17.4
node2    NotReady   <none>   19s     v1.17.4

安装网络插件：

kubernetes支持多种网络插件，比如flannel、calico、canal等等，任选一种使用即可，本次选择flannel

#master节点安装 获取fannel的配置文件，这个文件是外网的，如果下载不下来可以用下面提供的文件
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
# 使用配置文件启动flannel
kubectl apply -f kube-flannel.yml

kube-flannel.yml文件：

---
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: flannelcni/flannel-cni-plugin:v1.0.1 for ppc64le and mips64le (dockerhub limitations may apply)
        image: rancher/mirrored-flannelcni-flannel-cni-plugin:v1.0.1
        command:
        - cp
        args:
        - -f
        - /flannel
        - /opt/cni/bin/flannel
        volumeMounts:
        - name: cni-plugin
          mountPath: /opt/cni/bin
      - name: install-cni
       #image: flannelcni/flannel:v0.17.0 for ppc64le and mips64le (dockerhub limitations may apply)
        image: rancher/mirrored-flannelcni-flannel:v0.17.0
        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:v0.17.0 for ppc64le and mips64le (dockerhub limitations may apply)
        image: rancher/mirrored-flannelcni-flannel:v0.17.0
        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

执行完 kubectl apply后可以通过 kubectl get pods -A 查看pods是否创建成功，这里需要多等待下，等到pods的状态都为就绪状态就表示安装成功了。

#稍等片刻再次查看集群状态
kubectl get nodes

卸载k8s

# 每个结点上执行
kubectl delete -f kube-flannel.yml
kubeadm reset
rm -rf $HOME/.kube
rm -rf /etc/cni/net.d

参考 k8s学习笔记