Kubernetes 部署

Posted Mar 17, 2021

By Cc 12 min read

Kubernetes 搭建

准备

在搭建 Kubernetes 之前，您需要先准备一些必要的配置和工具，包括：

至少三个节点：用于部署 Kubernetes 集群的主机。一般情况下，建议使用至少三个物理或虚拟机来搭建 Kubernetes 集群，以确保高可用性和容错性。
操作系统：Kubernetes 支持多种操作系统，例如 Ubuntu、CentOS 等。建议使用最新版本的操作系统，并按照官方文档进行配置。
容器运行时：Kubernetes 支持多种容器运行时，如 Docker、Containerd、CRI-O 等。建议使用 Docker 作为容器运行时。
Kubernetes 工具集：Kubernetes 提供了一些工具，例如 kubeadm、kubectl 和 kubelet 等，用于搭建、管理和监控 Kubernetes 集群。
网络插件：Kubernetes 需要一个网络插件来处理容器网络通信。常见的网络插件有 Calico、Flannel 和 Weave Net 等。

接下来是 Kubernetes 的搭建步骤：

在每个节点上安装 Docker 和 Kubernetes 工具集。
使用 kubeadm 工具初始化 Kubernetes 控制节点，并创建一个 Kubernetes 集群。
添加更多的节点到 Kubernetes 集群中。
安装和配置网络插件，以实现容器网络通信。
部署应用程序和服务到 Kubernetes 集群中，并通过 kubectl 命令进行管理和监控。

最低配置

Kubernetes 的硬件要求主要由 Master 节点和 Node 节点的配置决定。以下是 Kubernetes 推荐的最低硬件配置：

Master 节点：
- CPU：至少 2 核心
- 内存：至少 2 GB RAM
- 磁盘空间：至少 20 GB
Node 节点：
- CPU：至少 2 核心
- 内存：至少 2 GB RAM
- 磁盘空间：至少 20 GB

需要注意的是，以上硬件配置只是 Kubernetes 的最低要求，如果您希望集群具有更好的性能和可靠性，可以考虑增加 CPU、内存和磁盘空间等资源。

搭建前 master/node

在部署 Kubernetes 集群之前，您需要进行一些节点的预配置工作。下面是一些常见的命令，用于关闭防火墙、Swap 分区、SELinux，并修改主机名：

关闭防火墙：

# CentOS 7/8
systemctl stop firewalld
systemctl disable firewalld

# Ubuntu 16.04/18.04/20.04
ufw disable

关闭 Swap 分区（建议在所有节点上执行）：

        
swapoff -a
sed -i '/ swap / s/^/#/' /etc/fstab

关闭 SELinux：

        
setenforce 0
sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

修改主机名（每个节点都要执行）：
1 hostnamectl set-hostname <NEW_HOSTNAME>

查看查询系统基本信息

        
      
uname -a #  查看版本当前操作系统内核信息
cat /proc/version # 查看当前系统版本信息
cat /etc/issue # 查看版本当前操作系统发行版本信息
cat /etc/redhat-release # 查看版本当前操作系统发行版本信息
cat /proc/cpuinfo  # OR lscpu 查看CPU相关信息，包括型号、主频、内核信息
getconf LONG_BIT # 看版本说明当前CPU运行在32bit模式下， 但不代表CPU不支持64bit
hostname # 查看服务器名称

# 查看网络信息
cat /etc/sysconfig/network-scripts/ifcfg-ens*
cat /etc/sysconfig/network-scripts/ifcfg-lo
ifconfig

lsblk # 查看磁盘信息 - 列出所有可用块设备的信息，而且还能显示他们之间的依赖关系，但是它不会列出RAM盘的信息
fdisk -l # 观察硬盘实体使用情况，也可对硬盘分区
df -k # df -k # 用于显示磁盘分区上的可使用的磁盘空

env # 查看环境变量
iptables -L # 查看防火墙设置
route -n # 查看路由表
swapon -s # 查看所有交换分区
w # 查看活动用户
last # 查看用户登录信息

搭建前准备（master/node）

关闭防火墙

systemctl stop firewalld
systemctl disable firewalld
systemctl status firewalld # 查看下状态

警用 Swp

vim /etc/fstab
# 注释 swap 行
swapoff -a

关闭 selinux

        
      
sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config # 永久关闭

修改主机名

        
      
hostnamectl set-hostname master # 永久生效 但需要重启
hostnamectl set-hostname nodeOne # 永久生效 但需要重启
hostnamectl set-hostname nodeTwo # 永久生效 但需要重启
reboot # 重启

修改hosts
1 vim /etc/hosts

安装 docker 20.10.1 （master/node）

        
      
#!/bin/bash

yum remove runc -y
yum install container-selinux yum-utils ipvsadm -y
rpm -ivh https://mirrors.aliyun.com/docker-ce/linux/centos/7/x86_64/stable/Packages/containerd.io-1.4.3-3.1.el7.x86_64.rpm
yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
yum clean all
yum makecache
yum install docker-ce docker-ce-cli -y

mkdir -p /data/docker /data/kubelet  /etc/docker /data/kubelet/plugins/nasplugin.csi.alibabacloud.com
touch  /etc/docker/daemon.json

cat > /etc/docker/daemon.json <<EOF
{
    "data-root": "/data/docker",
    "registry-mirrors": [
        "https://6mrynkvw.mirror.aliyuncs.com"
    ],
    "exec-opts": ["native.cgroupdriver=systemd"],
    "log-driver": "json-file",
    "log-opts": {
        "max-size": "100m"
    },
    "storage-driver": "overlay2",
    "storage-opts": [
        "overlay2.override_kernel_check=true"
            ]
    }
EOF
systemctl enable docker && systemctl start docker

设置阿里云 yum 软件源（master/node）

        
      
cat > /etc/yum.repos.d/kubernetes.repo << EOF
[k8s]
name=k8s
enabled=1
gpgcheck=0
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
EOF

安装 kubeadm、kubelet、kubectl （master/node）

        
 yum install -y kubelet-1.19.2 kubectl-1.19.2 kubeadm-1.19.2
 systemctl enable kubelet

kubernetes init （master）

        
      
 echo "1" >/proc/sys/net/bridge/bridge-nf-call-iptables
 kubeadm init \
  --apiserver-advertise-address=172.13.8.15 \
  --image-repository registry.aliyuncs.com/google_containers \
  --kubernetes-version v1.19.2 \
  --service-cidr=10.1.0.0/16 \
  --pod-network-cidr=10.244.0.0/16

成功信息

        
      
[bootstrap-token] configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[bootstrap-token] Creating the "cluster-info" ConfigMap in the "kube-public" namespace
[kubelet-finalize] Updating "/etc/kubernetes/kubelet.conf" to point to a rotatable kubelet client certificate and key
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy

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

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 172.13.8.15:6443 --token etvpqx.urx0nmbm4w4wwmt9 \
    --discovery-token-ca-cert-hash sha256:744f6cd77ba585411ddde4a8ed181859c17643df0c90ba4ec7eb859b69875bcd

输入创建测试是否 OK（master/node）

        
      
  scp admin.conf root@172.13.8.17:/etc/kubernetes
  scp admin.conf root@172.13.8.16:/etc/kubernetes
  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

  kubectl get nodes  # 测试

安装网络插件

        
      
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml # 会提示报错，修改hosts
# 追加hosts
# 199.232.28.133 raw.githubusercontent.com

node 加入 master 集群中

        
      
# 在成功init 成功之后输出的内容
kubeadm join 172.13.8.15:6443 --token etvpqx.urx0nmbm4w4wwmt9 \
    --discovery-token-ca-cert-hash sha256:744f6cd77ba585411ddde4a8ed181859c17643df0c90ba4ec7eb859b69875bcd

后记

kubeadm init 之后没有来得及记录 join 信息

        
      
#再生成一个token即可
kubeadm token create --print-join-command
#下在的命令可以查看历史的token
kubeadm token list

node join 失败后重新 join

        
      
#先执行
kubeadm -y reset
#再执行
kubeadm join  xx.....

重启 kubelet

systemctl daemon-reload
systemctl restart kubelet

维护

ROLES 为 none

kubectl label node nodeone node-role.kubernetes.io/worker=worker
kubectl label node nodetwo node-role.kubernetes.io/worker=worker

Error

/proc/sys/net/bridge/bridge-nf-call-iptables contents are not set to 1

        
      
echo "1" >/proc/sys/net/bridge/bridge-nf-call-iptables # 解决方法

插件`yml`

kube-flannel.yml

        
      
---
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

DevOps, Kubernetes

LinuxTool Kubernetes

This post is licensed under CC BY 4.0 by the author.