ubuntu18.04 搭建k8s

需求：

• 搭建k8s 为后续自动部署做准备

进程：

• 安装至少两个ubuntu18.04系统（一个master 一到多个 node）

• 每个系统上都要装上docker 和 kubernetes

• 安装docker

sudo su
apt-get update

#安装相关插件
apt-get install apt-transport-https ca-certificates curl gnupg lsb-release software-properties-common -y

#获取docker 对应的key 
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
#修改源
add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
         $(lsb_release -cs) \
         stable"
apt-get update

#安装docker 及相关部件
apt-get install docker-ce docker-ce-cli containerd.io -y

#查看docker 是否安装正常
docker --version

#启动docker 并设置开机自启
sudo systemctl daemon-reload && sudo systemctl restart docker && sudo systemctl enable docker

• 安装kubernetes

#基于上面安装的插件，可以直接获取kubernetes 的key
curl https://mirrors.aliyun.com/kubernetes/apt/doc/apt-key.gpg | apt-key add -

cat </etc/apt/sources.list.d/kubernetes.list
deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main
EOF

#查看一下是否成功
cat /etc/apt/sources.list.d/kubernetes.list

apt-get update
#安装kubernetes 及相关部件
apt-get install -y kubelet=1.19.2-00 kubeadm=1.19.2-00 kubectl=1.19.2-00 kubernetes-cni

#启动并设置开机自启
sudo systemctl enable kubelet && systemctl start kubelet

#查看是否成功
kubectl version

• 启动 kubernetes 可能会失败需要关闭 Swap

sudo swapoff -a #暂时关闭
nano /etc/fstab #永久关闭，注释掉swap那一行，推荐永久关闭

• 如果装了 selinux 需要关闭

setenforce 0 #临时

• 关闭防火墙

#查看防火墙状态如果是inactive 可以跳过
ufw status #查看防火墙状态
ufw disable #关闭防火墙

• 配置iptables

#配置之前可以先查看一下本地配置是不是好的如果本身就正常可以跳过
#sysctl net.ipv4.ip_forward
#sysctl net.bridge.bridge-nf-call-ip6tables
#sysctl net.bridge.bridge-nf-call-iptables

cat >> /etc/sysctl.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF
sysctl -p                                            #执行此命令生效配置

• 初始化master

# --pod-network-cidr pod 的网段
# --apiserver-advertise-address master 的ip
#记得替换成自己的
kubeadm init --image-repository registry.cn-hangzhou.aliyuncs.com/google_containers --pod-network-cidr=192.168.197.0/16 --apiserver-advertise-address=192.168.197.135

#init 成功后最后会有一段话返回
Your Kubernetes control-plane has initialized successfully!

#你需要在普通权限下运行以下命令
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

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/

#你可以把node 通过以下命令挂到master 下
Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 192.168.197.135:6443 --token hbbn5i.u6fqjr0phforyr2q \
    --discovery-token-ca-cert-hash sha256:e3f40cb90a3d791deaf6b6606ec500cffc8b48d0351b085cd0d4f74a6ce0e794

• 配置flannel 通信

#两个文件在末尾
kubectl create -f kube-flannel-rbac.yml
kubectl create -f kube-flannel.yml

#上面两条有时候不需要 master 和 node 都需要哦
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

• 将node 挂到 master 上

#如果之前join 过需要先resert
kubeadm reset

#如果上面那个join 忘了可以重新生成token
kubeadm token create --print-join-command

#然后再node 上运行返回的 内容

• 在node 上运行可能会失败报错The connection to the server localhost:8080 was refused - did you specify the right host or port?

• 在master 里找到文件 /etc/kubernetes/admin.conf 拷贝到node 下

echo "export KUBECONFIG=/etc/kubernetes/admin.conf" >> /etc/profile
source /etc/profile

• 重新运行join

• 查看node 的状态

kubectl get nodes

• 返回的状态都为Ready 表示创建完成

拓展：

• kube-flannel-rbac.yml

---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: flannel
rules:
  - apiGroups:
      - ""
    resources:
      - pods
    verbs:
      - get
  - apiGroups:
      - ""
    resources:
      - nodes
    verbs:
      - list
      - watch
  - apiGroups:
      - ""
    resources:
      - nodes/status
    verbs:
      - patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: flannel
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: flannel
subjects:
- kind: ServiceAccount
  name: flannel
  namespace: kube-system

• kube-flannel.yml

---
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
- apiGroups:
  - "networking.k8s.io"
  resources:
  - clustercidrs
  verbs:
  - list
  - watch
---
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: docker.io/flannel/flannel-cni-plugin:v1.1.2
       #image: docker.io/rancher/mirrored-flannelcni-flannel-cni-plugin:v1.1.2
        command:
        - cp
        args:
        - -f
        - /flannel
        - /opt/cni/bin/flannel
        volumeMounts:
        - name: cni-plugin
          mountPath: /opt/cni/bin
      - name: install-cni
        image: docker.io/flannel/flannel:v0.20.2
       #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: docker.io/flannel/flannel:v0.20.2
       #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"
        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