--- url: /diary/k8s/02/index.md description: Kubernetes 学习笔记第二篇，在 CentOS 7 裸机上搭建生产级 K8S 集群，包括 master 和 worker 节点配置。 --- ## 前言 ### 主节点组件 * docker（或其他容器） * kubectl * kubeadm ### 工作节点组件 * docker * kubectl ## 生产环境搭建 本次使用3台虚拟机模拟节点，以`centOs7`系统做演示 1. 初始(所有节点)，操作为三台机器共同操作，将3台虚拟机分别命名为 * master `192.168.171.130` * node1 `192.168.171.131` * node2 `192.168.171.132` 2. 修改3台机器的hosts ```shell vim /etc/hosts #加入以下内容 192.168.171.130 master 192.168.171.131 node1 192.168.171.132 node2 ``` 3. 设置SELinux ```shell #将 SELinux 设置为 permissive 模式（相当于将其禁用） sudo setenforce 0 sudo sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config #或者直接禁用 setenforce 0 sed -i --follow-symlinks 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/sysconfig/selinux ``` 4. 关闭swap 需关闭swap，否则 kubelet 无法正常工作 ```shell swapoff -a yes | cp /etc/fstab /etc/fstab_bak cat /etc/fstab_bak |grep -v swap > /etc/fstab ``` 5. 添加k8s安装源 ```shell # 添加 k8s 安装源 cat < kubernetes.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 mv kubernetes.repo /etc/yum.repos.d/ ``` 6. 添加docker安装源 ```shell # 添加 Docker 安装源 yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo ``` 7. 安装所需组件 ```shell yum install -y kubelet kubeadm kubectl docker-ce #设置开机启动 systemctl enable kubelet systemctl start kubelet systemctl enable docker systemctl start docker ``` 8. 修改docker配置 > \[!warning] > 必须修改`docker`配置，否则`kubelet` 无法正常工作 ```shell # kubernetes 官方推荐 docker 等使用 systemd 作为 cgroupdriver，否则 kubelet 启动不了 cat < daemon.json { "exec-opts": ["native.cgroupdriver=systemd"], "registry-mirrors": ["https://ud6340vz.mirror.aliyuncs.com"] } EOF mv daemon.json /etc/docker/ ``` ### 初始化集群（master） #### 初始化 ```shell kubeadm init --image-repository=registry.aliyuncs.com/google_containers --pod-network-cidr 10.244.0.0/16 ``` * 成功后提示类似如下，其中`kubeadm join xxx` 需保存起来 ```shell Then you can join any number of worker nodes by running the following on each as root: kubeadm join 192.168.171.130:6443 --token eez76b.z8xu5q1510sps4vv \ --discovery-token-ca-cert-hash sha256:038b319037ec6ec9a1daf1a81f9e7fd762 a5427a63aedadd71ac7aee49b6eb7a ``` * 如果`kubeadm join xxx` 丢失，可以重新获取： ```shell kubeadm token create --print-join-command ``` * 如果初始化失败，则可以进行重置，然后再初始化： ```shell kubeadm reset kubeadm init --image-repository=registry.aliyuncs.com/google_containers --pod-network-cidr 10.244.0.0/16 ``` #### 复制授权文件 ```shell # 复制授权文件，以便 kubectl 可以有权限访问集群 mkdir -p $HOME/.kube cp -i /etc/kubernetes/admin.conf $HOME/.kube/config chown $(id -u):$(id -g) $HOME/.kube/config ``` #### 安装网络插件 > \[!warning] > 必须安装网络插件，否则node的`STATUS`是 `NotReady` > \[!warning] > 在安装网络之前，集群 DNS (CoreDNS) 将不会启动。 > \[!warning] > 注意你的 Pod 网络最好不与任何主机网络重叠 网络插件可以[参考](https://kubernetes.io/zh/docs/concepts/cluster-administration/networking/#how-to-implement-the-kubernetes-networking-model) ```shell #Flannel ## Flannel 是一个非常简单的能够满足 Kubernetes 所需要的覆盖网络。 kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml ``` * 如果下载失败，可以使用以下文件直接安装 ```yml :collapsed-lines --- 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 ``` 保存为`kube-flannel.yml` 文件，并运行以下命令： ```shell [root@master .kube]# kubectl apply -f kube-flannel.yml Warning: policy/v1beta1 PodSecurityPolicy is deprecated in v1.21+, unavailable i n v1.25+ podsecuritypolicy.policy/psp.flannel.unprivileged created clusterrole.rbac.authorization.k8s.io/flannel created clusterrolebinding.rbac.authorization.k8s.io/flannel created serviceaccount/flannel created configmap/kube-flannel-cfg created daemonset.apps/kube-flannel-ds created ``` ### 加入集群（node） 分别在`node1` 和 `node2` 上加入集群 #### 加入命令 ```shell kubeadm join 192.168.171.130:6443 --token eez76b.z8xu5q1510sps4vv \ --discovery-token-ca-cert-hash sha256:038b319037ec6ec9a1daf1a81f9e7fd762 a5427a63aedadd71ac7aee49b6eb7a ``` ### 查看集群（master） ```shell [root@master .kube]# kubectl get nodes NAME STATUS ROLES AGE VERSION master Ready control-plane,master 56m v1.23.1 node1 Ready 52m v1.23.1 node2 Ready 50m v1.23.1 ```