K8S 学习笔记 02 裸机安装搭建K8S生产环境

约 1219 字大约 4 分钟

KubernetesCentOS集群搭建生产环境

次阅读

2023-03-20

⚠ 请注意，本文编写于 1115 天前，最后修改于 1115 天前，其中某些信息可能已经过时。

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

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

修改3台机器的hosts

vim /etc/hosts
#加入以下内容
192.168.171.130 master
192.168.171.131 node1
192.168.171.132 node2

设置SELinux

#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

关闭swap

需关闭swap，否则 kubelet 无法正常工作

swapoff -a
yes | cp /etc/fstab /etc/fstab_bak
cat /etc/fstab_bak |grep -v swap > /etc/fstab

添加k8s安装源

# 添加 k8s 安装源
cat <<EOF > 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/

添加docker安装源

# 添加 Docker 安装源
yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

安装所需组件

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

修改docker配置

注意

必须修改docker配置，否则kubelet 无法正常工作

# kubernetes 官方推荐 docker 等使用 systemd 作为 cgroupdriver，否则 kubelet 启动不了
cat <<EOF > 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

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

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：
```
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：

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

# 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

注意

必须安装网络插件，否则node的STATUS是 NotReady

注意

在安装网络之前，集群 DNS (CoreDNS) 将不会启动。

注意

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

#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

---
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：

[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

kubeadm join 192.168.171.130:6443 --token eez76b.z8xu5q1510sps4vv \
        --discovery-token-ca-cert-hash sha256:038b319037ec6ec9a1daf1a81f9e7fd762      a5427a63aedadd71ac7aee49b6eb7a

查看集群（master）

[root@master .kube]# kubectl get nodes
NAME     STATUS   ROLES                  AGE   VERSION
master   Ready    control-plane,master   56m   v1.23.1
node1    Ready    <none>                 52m   v1.23.1
node2    Ready    <none>                 50m   v1.23.1

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