[最新] kubeadm 安装使用 Kubernetes 1.20.4

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whale_life 2021-03-08 18:06:44 博主文章分类：kubernetes ©著作权

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版本介绍

CentOS 7.9 内核版本 5.4.101 升级内核操作请移步此链接

kubernetes v1.20.4

节点角色	节点介绍	IP地址
master	node-1	192.168.202.71
node	node-2	192.168.202.72
node	node-3	192.168.202.73
node	node-4	192.168.202.74
node	node5	192.168.202.75

1.各节点均需要执行的准备操作

# 升级内核版本至 CentOS7 的最信LT版本的内核

# 关闭swap：
# 临时关闭
swapoff -a
# 永久关闭(删除或注释掉swap那一行重启即可)
vim /etc/fstab

# 各节点使用 ipvs
cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack
EOF
chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4
yum install ipvsadm ipset -y
# ipvsadm -ln
#可以看到service对应的很多规则

# 各节点分别执行设定主机名
[root@node-1 ~]# hostnamectl set-hostname node-1
...

# 各节点解析
[root@node-1 ~]# cat /etc/hosts
192.168.202.71 node-1
192.168.202.72 node-2
192.168.202.73 node-3
192.168.202.74 node-4
192.168.202.75 node-5

# node-1 节点设置为 master 节点，其余节点为 node 节点，需要设置 master 节点至 node 节点的免密登录
[root@node-1 ~]# ssh-keygen
[root@node-1 ~]# ssh-copy-id node-1
[root@node-1 ~]# ssh-copy-id node-2
[root@node-1 ~]# ssh-copy-id node-3
[root@node-1 ~]# ssh-copy-id node-4
[root@node-1 ~]# ssh-copy-id node-5

# 各节点优化参数
[root@node-1 ~]# tee /etc/sysctl.conf <<-"EOF"
net.ipv4.ip_local_port_range = 1024 65535
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_fin_timeout = 30
net.core.somaxconn = 20480
net.core.netdev_max_backlog = 20480
net.ipv4.tcp_max_syn_backlog = 20480
net.ipv4.tcp_max_tw_buckets = 800000
net.bridge.bridge-nf-call-iptables=1
net.bridge.bridge-nf-call-ip6tables=1
net.ipv4.ip_forward=1
EOF

# 安装docker
[root@node-1 ~]# wget -P /etc/yum.repos.d/ https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
[root@node-1 ~]# yum install docker-ce -y

# 修改 docker 的启动用户组
[root@node-1 ~]# sed -i s/SocketGroup=docker/SocketGroup=root/g /usr/lib/systemd/system/docker.socket

# 修改 docker 的 cgroup 驱动为 systemd
[root@node-1 ~]# cat /etc/docker/daemon.json
{
    "registry-mirrors": [
        "https://by0gaj4f.mirror.aliyuncs.com"
    ],
    "exec-opts": [
        "native.cgroupdriver=systemd"
    ],
    "log-driver": "json-file",
    "log-opts": {
        "max-size": "100m"
    },
    "storage-driver": "overlay2"
}

[root@node-1 ~]# systemctl daemon-reload
[root@node-1 ~]# systemctl enable docker
[root@node-1 ~]# systemctl restart docker


[root@node-1 ~]# cat <<EOF > /etc/yum.repos.d/kubernets.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
[root@node-1 ~]# for i in {2..5}; do scp /etc/yum.repos.d/kubernets.repo node-$i:/etc/yum.repos.d/ ; done

2.安装 kubernetes 相关组件

[root@node-1 ~]# yum help | grep show
  --showduplicates      在 list/search 命令下，显示源里重复的条目
[root@node-1 ~]# yum list kubeadm --showduplicates

# 指定版本
[root@node-1 ~]# yum install kubeadm-1.20.4 kubectl-1.20.4 kubelet-1.20.4 -y

# 每个节点都需要执行
[root@node-1 ~]# systemctl enable kubelet

3.kubernetes 初始化集群

# master 节点执行
[root@node-1 ~]# kubeadm config images list
k8s.gcr.io/kube-apiserver:v1.20.4
k8s.gcr.io/kube-controller-manager:v1.20.4
k8s.gcr.io/kube-scheduler:v1.20.4
k8s.gcr.io/kube-proxy:v1.20.4
k8s.gcr.io/pause:3.2
k8s.gcr.io/etcd:3.4.13-0
k8s.gcr.io/coredns:1.7.0

[root@node-1 ~]# kubeadm init \
--apiserver-advertise-address=192.168.202.71 \
--apiserver-bind-port=6443 \
--image-repository="registry.aliyuncs.com/google_containers" \
--kubernetes-version="v1.20.4" \
--pod-network-cidr="10.244.0.0/16"
# 执行结果
Your Kubernetes control-plane has initialized successfully!

To start using your cluster, you need to run the following as a regular user:

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

Alternatively, if you are the root user, you can run:

  export KUBECONFIG=/etc/kubernetes/admin.conf

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:

kubeadm join 192.168.202.71:6443 --token k1qppu.cnlypnu9krd9b6k1 \
    --discovery-token-ca-cert-hash sha256:1dcf1d358ca12d7b042809cd47999df7fcd143a9f583b1c3a880d5a72191d783

# 执行上述命令
  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

# node 节点执行
kubeadm join 192.168.202.71:6443 --token k1qppu.cnlypnu9krd9b6k1 \
    --discovery-token-ca-cert-hash sha256:1dcf1d358ca12d7b042809cd47999df7fcd143a9f583b1c3a880d5a72191d783

# 查看验证
[root@node-1 ~]# kubectl get nodes
NAME     STATUS     ROLES                  AGE     VERSION
node-1   NotReady   control-plane,master   17m     v1.20.4
node-2   NotReady   <none>                 6m59s   v1.20.4
node-3   NotReady   <none>                 6m59s   v1.20.4
node-4   NotReady   <none>                 6m59s   v1.20.4
node-5   NotReady   <none>                 6m59s   v1.20.4

4.安装网络插件 Flannel

flannel/kube-flannel.yml at master · flannel-io/flannel · GitHub

[root@node-1 ~]# kubectl apply -f kube-flannel.yml
# 状态修改为 Ready
[root@node-1 ~]# kubectl get nodes
NAME     STATUS   ROLES                  AGE   VERSION
node-1   Ready    control-plane,master   35m   v1.20.4
node-2   Ready    <none>                 24m   v1.20.4
node-3   Ready    <none>                 24m   v1.20.4
node-4   Ready    <none>                 24m   v1.20.4
node-5   Ready    <none>                 24m   v1.20.4

---
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
        image: quay.io/coreos/flannel:v0.13.1-rc2
        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:v0.13.1-rc2
        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
        hostPath:
          path: /etc/cni/net.d
      - name: flannel-cfg
        configMap:
          name: kube-flannel-cfg

5.命令行补全

[root@node-1 ~]# kubectl completion bash > /etc/profile.d/kubectl.sh
[root@node-1 ~]# source /etc/profile.d/kubectl.sh
[root@node-1 ~]# echo "source /etc/profile.d/kubectl.sh" >> .bashrc
[root@node-1 ~]# cat .bashrc
# .bashrc

# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi
source /etc/profile.d/kubectl.sh

6.查看健康状态并修改ipvs模型

[root@node-1 ~]# kubectl get pods -n kube-system -o wide
NAME                             READY   STATUS    RESTARTS   AGE   IP               NODE     NOMINATED NODE   READINESS GATES
coredns-7f89b7bc75-2cmfc         1/1     Running   0          46m   10.244.3.2       node-4   <none>           <none>
coredns-7f89b7bc75-59zft         1/1     Running   0          46m   10.244.1.2       node-2   <none>           <none>
etcd-node-1                      1/1     Running   0          46m   192.168.202.71   node-1   <none>           <none>
kube-apiserver-node-1            1/1     Running   0          46m   192.168.202.71   node-1   <none>           <none>
kube-controller-manager-node-1   1/1     Running   0          46m   192.168.202.71   node-1   <none>           <none>
kube-flannel-ds-4qq8g            1/1     Running   0          17m   192.168.202.72   node-2   <none>           <none>
kube-flannel-ds-9pc7w            1/1     Running   0          17m   192.168.202.75   node-5   <none>           <none>
kube-flannel-ds-hqkjv            1/1     Running   0          17m   192.168.202.74   node-4   <none>           <none>
kube-flannel-ds-ncrh4            1/1     Running   0          17m   192.168.202.71   node-1   <none>           <none>
kube-flannel-ds-qk77w            1/1     Running   0          17m   192.168.202.73   node-3   <none>           <none>
kube-proxy-8qzg8                 1/1     Running   0          35m   192.168.202.72   node-2   <none>           <none>
kube-proxy-crklz                 1/1     Running   0          35m   192.168.202.75   node-5   <none>           <none>
kube-proxy-mb6n8                 1/1     Running   0          35m   192.168.202.73   node-3   <none>           <none>
kube-proxy-pwt6m                 1/1     Running   0          46m   192.168.202.71   node-1   <none>           <none>
kube-proxy-sdvnj                 1/1     Running   0          35m   192.168.202.74   node-4   <none>           <none>
kube-scheduler-node-1            1/1     Running   0          46m   192.168.202.71   node-1   <none>           <none>

[root@node-1 ~]# kubectl get daemonsets.apps -A
NAMESPACE     NAME              DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR            AGE
kube-system   kube-flannel-ds   5         5         5       5            5           <none>                   17m
kube-system   kube-proxy        5         5         5       5            5           kubernetes.io/os=linux   47m

[root@node-1 ~]# kubectl get service -A
NAMESPACE     NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)                  AGE
default       kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP                  47m
kube-system   kube-dns     ClusterIP   10.96.0.10   <none>        53/UDP,53/TCP,9153/TCP   47m

# 修改为ipvs模式
[root@node-1 ~]# kubectl edit configmap kube-proxy -n kube-system

   minSyncPeriod: 0s
      scheduler: ""
      syncPeriod: 30s
    kind: KubeProxyConfiguration
    metricsBindAddress: 127.0.0.1:10249
    mode: "ipvs"                          # 修改此处
    nodePortAddresses: null
 
# 删除所有kube-proxy的pod
[root@node-1 ~]# for i in `kubectl get pods -n kube-system | grep kube-proxy | awk '{print $1}'`; do kubectl delete pod $i -n kube-system ;done
pod "kube-proxy-8qzg8" deleted
pod "kube-proxy-crklz" deleted
pod "kube-proxy-mb6n8" deleted
pod "kube-proxy-pwt6m" deleted
pod "kube-proxy-sdvnj" deleted
[root@node-1 ~]# kubectl get pods -n kube-system | grep kube-proxy
kube-proxy-7ng6v                 1/1     Running   0          18s
kube-proxy-fvkgv                 1/1     Running   0          13s
kube-proxy-gvr7t                 1/1     Running   0          11s
kube-proxy-j4wxh                 1/1     Running   0          17s
kube-proxy-jqpn9                 1/1     Running   0          3s
[root@node-1 ~]# kubectl logs -n kube-system kube-proxy-7ng6v
I0304 01:15:04.995911       1 server_others.go:258] Using ipvs Proxier.

# 验证
[root@node-1 ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.96.0.1:443 rr
  -> 192.168.202.71:6443          Masq    1      0          0
TCP  10.96.0.10:53 rr
  -> 10.244.1.2:53                Masq    1      0          0
  -> 10.244.3.2:53                Masq    1      0          0
TCP  10.96.0.10:9153 rr
  -> 10.244.1.2:9153              Masq    1      0          0
  -> 10.244.3.2:9153              Masq    1      0          0
UDP  10.96.0.10:53 rr
  -> 10.244.1.2:53                Masq    1      0          0
  -> 10.244.3.2:53                Masq    1      0          0

参考：

https://www.cnblogs.com/276815076/p/4673607.html

https://blog.csdn.net/CEVERY/article/details/109104447

https://blog.csdn.net/weixin_42914965/article/details/106213069