kubeadm 部署 k8s

打算将自己的小项目搬到K8S上，学习了一波，顺便做一下笔记，方便之后查阅。

环境准备：
centos 7.8，	2*2核CPU，  2G内存
node2：192.168.157.137			作为master节点
node3：192.168.157.138			作为work节点

保证集群内所有机器可以互相ping通
保证机器可以连接外网（非必要，可以连接本地docker仓库）

# 没有特殊说明就是在所有机器上都执行。

1. 禁止swap分区
	swapoff -a		# 临时关闭

	vim /etc/fstab		# 永久关闭，需要重启机器
	# /dev/mapper/centos-swap  swap  swap  defaults  0 0		# 注释掉

	echo vm.swappiness=0  >> /etc/sysctl.conf

# 如上图，swap关闭


2. 关闭防火墙，selinux，配置hosts文件，设置ntp时间同步


3. 设置网桥参数：
	vim /etc/sysctl.d/k8s.conf
	net.bridge.bridge-nf-call-ip6tables = 1
	net.bridge.bridge-nf-call-iptables = 1

	sysctl --system		# 配置内核参数（加载网桥参数）


4. 安装docker：
	yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo		# 获取阿里云docker镜像

	yum -y install docker-ce-19.03.13

	vim /etc/docker/daemon.json		# 为了加快镜像下载速度
	{
	 	"registry-mirrors": ["https://registry.docker-cn.com"]
	 	// 科大镜像：  https://docker.mirrors.ustc.edu.cn/
	}
	
	systemc enable docker
	systemc start docker


5. 添加阿里云K8S的yum源
	[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

# 其它yum源我也使用阿里的了
cd /etc/yum.repos.d
wget http://mirrors.aliyun.com/repo/epel-7.repo
wget http://mirrors.aliyun.com/repo/Centos-7.repo


6. 安装kubeadm，kubelet，kubectl：  （在github上找的release版本，1.21.2下载镜像有那么一丢丢麻烦。先用1.20.8这个版本）
	# kubeadm：管理集群的脚本
	# kubelet：用于启动pod和容器
	# kubectl：K8S命令行工具

	yum -y install kubelet-1.20.8 kubeadm-1.20.8 kubectl-1.20.8

	systemctl enable kubelet

	# 踩坑：千万不要 start，不然在init的时候会报错，init会自动启动kubelet


7. 初始化master	（master上执行）
kubeadm init \	
--kubernetes-version=v1.20.8 \		# K8S版本
--apiserver-advertise-address=192.168.157.137 \		# master ip地址
--image-repository=registry.cn-hangzhou.aliyuncs.com/google_containers \		# 镜像仓库 阿里云的
--service-cidr=10.96.0.0/12 \
--pod-network-cidr=10.244.0.0/16		# flannel默认网段

# 执行这条命令就是到对应的仓库中下载相关的镜像，执行完毕之后的镜像如下图所示：

# 初始化之后会生成对应命令，在work节点上执行第二个红色箭头指向的命令，就可以将wokr节点加入到集群中了。

# 复制配置文件		init成功之后也有提示
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

kubectl get nodes	# 查询集群节点信息

补充一下：也可以采用配置文件的方式初始化集群
kubeadm config print init-defaults > k8s-init.yml
kubeadm init --config=k8s-init.yml		# 配置文件按需修改。


8. 将work节点加入到集群中 （work节点上执行）
# 这条命令在work节点上执行就可以将节点加入到集群
kubeadm join 192.168.157.137:6443 --token tlkqrd.z2lrv6tgwdwyj5w4 \
--discovery-token-ca-cert-hash sha256:334f3f80b5e2a0ca6a63209bad8a110ebd8988db12cde92fe98618e69ce90728

# 最终结果如下，node3是work节点

# 状态status是NotReady，还需要进行网络的配置


9. 配置网络flannel
	# 配置文件不太好找
	kubectl apply -f kube-flannel.yml			# 根据文件创建pod，稍等一会儿

	kubectl get namespaces		# 查看所有的namespace
	kubectl get pods -n kube-system	# 查看对应namespace对应的pod


贴一下  kube-flannel.yml	 相关配置，不然下次不好找了

---
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:v0.13.0
        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: quay.io/coreos/flannel:v0.13.0
        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
        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

关于master的高可用，用到的时候再补充吧。

参考：https://kubernetes.io/zh/docs/reference/setup-tools/kubeadm/