kubeadm 搭建 K8s

kubeadm 搭建 K8s

本篇主要记录一下 使用 kubeadm 搭建 k8s 详细过程 ,环境使用 VirtualBox 构建的3台虚拟机

1.环境准备

  • 操作系统:Centos7 (CentOS Linux release 7.9.2009)
  • Master 主节点: 1台 虚拟机
  • Node 计算节点: 2台 虚拟机
  • K8s version:v1.23.5 (选的较新的版本)
  • Docker version:20.10.14

虚拟机创建我就不详细展开了

2.虚拟机网络配置(保证能访问外网)

虚拟机网卡 选择的是 1.网络地址转换NAT (主要用来访问外网的) 2.仅主机网络 (主要用来宿主机访问虚拟机的)

把对应的 ip 设置如下

kube-master 192.168.56.20

kube-node-1 192.168.56.21

kube-node-2 192.168.56.22

2.1 3台虚拟机 静态ip配置

cat /etc/sysconfig/network-scripts/ifcfg-enp0s3

TYPE="Ethernet"
PROXY_METHOD="none"
BROWSER_ONLY="no"
BOOTPROTO="none" #关闭
DEFROUTE="yes"
IPV4_FAILURE_FATAL="no"
IPV6INIT="yes"
IPV6_AUTOCONF="yes"
IPV6_DEFROUTE="yes"
IPV6_FAILURE_FATAL="no"
IPV6_ADDR_GEN_MODE="stable-privacy"
NAME="enp0s3"
UUID="35eac2d4-234d-4859-848e-ed2a30a64a81"
DEVICE="enp0s3"
#添加部分 
IPADDR="10.0.2.20"
PREFIX="24"
GATEWAY="10.0.2.2"
DNS1="10.0.2.3"
DNS2="114.114.114.114"
ONBOOT="yes"

cat /etc/sysconfig/network-scripts/ifcfg-enp0s8

TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=static #修改为 static 静态ip
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=enp0s8
UUID=d06bac6d-294f-4bfe-bf08-5cb65c0a431f
DEVICE=enp0s8
#新增部分
IPADDR=192.168.56.20
PREFIX=24
ONBOOT=yes

2.2 虚拟机hosts 配置

在 3台虚拟机 /etc/hosts 中配置 如下

192.168.56.20	kube-master
192.168.56.21	kube-node-1
192.168.56.22	kube-node-2

image-20220415170426999

3.k8s 基础环境设置

3.1 yum 换源(可选)

yum -y install wget

cd /etc/yum.repos.d
mv CentOS-Base.repo CentOS-Base.repo.bak
wget -O CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
yum clean all
yum makecache #重新生成缓存

3.2 关闭 selinux

setenforce 0 #临时关闭
sed -i "s/SELINUX=enforcing/SELINUX=disabled/g" /etc/selinux/config #永久关闭

3.3 关闭swap分区或禁用swap文件

swapoff -a
# 注释掉关于swap分区的行
yes | cp /etc/fstab /etc/fstab_bak
cat /etc/fstab_bak |grep -v swap > /etc/fstab

3.4 允许iptables 检查桥接流量

cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
br_netfilter
EOF

cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

sudo sysctl --system

3.5 关闭防火墙

systemctl stop firewalld
systemctl disable firewalld

3.6 /proc/sys/net/ipv4/ip_forward

echo 1 > /proc/sys/net/ipv4/ip_forward

4.kubectl、kubeadm、kubelet的安装

注意 先换源 https://developer.aliyun.com/mirror/kubernetes?spm=a2c6h.13651102.0.0.64be1b11iddYWH 阿里换源文档

4.1 添加Kubernetes的alibaba yum源

cat <<EOF > /etc/yum.repos.d/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

yum install -y kubelet kubeadm kubectl


4.2 安装 kubelet kubeadm kubectl

yum install -y kubelet kubeadm kubectl 
systemctl enable kubelet && systemctl start kubelet 

由于官网未开放同步方式, 可能会有索引gpg检查失败的情况, 这时请用 yum install -y --nogpgcheck kubelet kubeadm kubectl 安装

4.3 启动kubelet 服务

systemctl enable kubelet && systemctl start kubelet

此时执行systemctl status kubelet查看服务状态,此时肯定有错误(因为我们还未进行初始化操作),错误可使用journalctl -xe查看错误信息。

5.Docker 安装和配置

Docker centos 安装文档 地址 https://docs.docker.com/engine/install/centos/

5.1 Docker 安装

sudo yum install -y yum-utils

sudo yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo
    
    
sudo yum install docker-ce docker-ce-cli containerd.io 
# 也可以安装其他版本 yum list docker-ce --showduplicates | sort -r  
# sudo yum install docker-ce-<VERSION_STRING> docker-ce-cli-<VERSION_STRING> containerd.io

#启动docker
sudo systemctl enable docker && systemctl start docker 

5.2 Docker 镜像源更换

sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://9xxxx1clo.mirror.aliyuncs.com"] #请更换自己的 阿里云镜像地址
}
EOF

5.3 Docker 配置cgroup-driver

由于 cgroup-driver ,默认docker 是 cgroupfs ,而k8s 默认是 systemd,所以需要设置 docker 的 cgroup 为 systemd

推荐使用方式二进行修改

#查看cgroup-driver

 docker info | grep -i cgroup
# 方式一 追加 --exec-opt native.cgroupdriver=systemd 参数
 sed -i "s#^ExecStart=/usr/bin/dockerd.*#ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock --exec-opt native.cgroupdriver=systemd#g" /usr/lib/systemd/system/docker.service
 
 systemctl daemon-reload # 重新加载服务
 systemctl enable docker # 启用docker服务(开机自起)
 systemctl restart docker # 启动docker服务

# 方式二 修改docker配置文件
 vim /etc/docker/daemon.json
{
  "exec-opts": ["native.cgroupdriver=systemd"]
}

5.4 拉取k8s所需镜像

可以通过

kubeadm config images list 查看 所需的镜像

kubeadm config images list 

k8s.gcr.io/kube-apiserver:v1.23.5
k8s.gcr.io/kube-controller-manager:v1.23.5
k8s.gcr.io/kube-scheduler:v1.23.5
k8s.gcr.io/kube-proxy:v1.23.5
k8s.gcr.io/pause:3.6
k8s.gcr.io/etcd:3.5.1-0
k8s.gcr.io/coredns/coredns:v1.8.6

如果拉取不到镜像 可以通过 去 docker hub 上查找对应的 镜像

image-20220415171557414

docker pull k8simage/kube-apiserver:v1.23.5 
 
docker tag k8simage/kube-apiserver:v1.23.5 k8s.gcr.io/kube-apiserver:v1.23.5 #重新tag改成上面所需的镜像即可, 其他的都按照这样来

image-20220415172704185

Tips: 完成上面操作后 你可以通过 docker save 导出镜像,以后再用的时候 可以通过 docker image load < 进行离线加载镜像

#导出镜像 ,批量导出所有镜像

docker save $(docker images --format '{{.Repository}}:{{.Tag}}') -o k8s.images.tar 
#导入镜像 ,注意 是 < 不是 > 。。 > 后会导致tar 无法使用需要重新上传
docker image load < ...tar/zip 

6.kube-master 节点 初始化

我这里选的是 flannel 网络插件,先来看看 flannel 的配置文件

6.1 查看flannel 网络范围

flannel.yml https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml

不同的 网络插件 网络范围不同

image-20220415173212001

6.2 kubeadm init 初始化

kubeadm init --pod-network-cidr=10.244.0.0/16 \ #网卡插件的 网络范围  --apiserver-advertise-address=192.168.56.20 #master 的 ip 地址

等一会就会有如下结果

image-20220415173521177

可以把 kubeadm join 命令记下来 便于后面使用 保存输出中的kubeadm join部分内容,用于添加node节点,或者使用kubeadm token listkubeadm token create --print-join-command查看

执行后续步骤,可以看到提示

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

6.3 网络插件flannel 配置

前面提到了flannel 把对应的flannel.yml文件下载到服务器中,可以使用wget

可以看到 在没配置 flannel 的时候 coredns 一直是 pending 状态

image-20220414184915596

wget https://raw.githubusercontent.com/flannel-io/flannel/master/Documentation/kube-flannel.yml #可能会下载不到,文章最后我会提供内容,直接copy过去即可

#Tips: 可能需要指定一下网卡 ,在kube-flannel.yml中 - /opt/bin/flanneld args: 后面添加
#- --iface=enp0s8 # 需要指定网卡,否则可能k8s会导致使用错误的网卡 

kubectl apply -f kube-flannel.yml #应用该文件

image-20220414224216803

kubectl get pods --all-namespaces -o wide #查看是否安装成功,它会在 master 和 node 节点上都会自动部署

image-20220415175527461

最后通过 kubectl get nodes -o wide 查看 节点

7.kube-node 节点初始化

7.1 查看token

可以通过该命令进行查看 token

kubeadm token create --print-join-command

#kubeadm join kube-master:6443 --token ii5xyw.mywlktar1e8f60cu --discovery-token-ca-cert-hash sha256:358f92418178342f79aa7b049e6c18a423f0fb88186189142459016fe6efb8e7

7.2 node节点上 执行 kubeadmin join

kubeadm join kube-master:6443 --token ii5xyw.mywlktar1e8f60cu --discovery-token-ca-cert-hash sha256:358f92418178342f79aa7b049e6c18a423f0fb88186189142459016fe6efb8e7

7.3 在master 上查看结果

watch kubectl get nodes -o wide #可以通过watch 实时监听 加入情况

image-20220415180246749

至此使用 kubeadm 已经成功搭建k8s 集群

总结

本篇主要讲解了 如何使用 kubeadm 进行搭建 k8s 集群 ,搭建的是 k8s 较新版本 v1.23.5 版本,使用kubeadm 搭建相对来说还是比较简单的 。

k8s官网文档

https://kubernetes.io/zh/docs/setup/production-environment/tools/kubeadm/install-kubeadm/

阿里 k8s 更换镜像文档

https://developer.aliyun.com/mirror/kubernetes?spm=a2c6h.13651102.0.0.64be1b11iddYWH

Docker hub 地址

https://hub.docker.com/r/k8simage/

Docker 安装地址

https://docs.docker.com/engine/install/centos/

flannel.yml 文件

---
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: flannelcni/flannel-cni-plugin:v1.0.1 for ppc64le and mips64le (dockerhub limitations may apply)
        image: rancher/mirrored-flannelcni-flannel-cni-plugin:v1.0.1
        command:
        - cp
        args:
        - -f
        - /flannel
        - /opt/cni/bin/flannel
        volumeMounts:
        - name: cni-plugin
          mountPath: /opt/cni/bin
      - name: install-cni
       #image: flannelcni/flannel:v0.17.0 for ppc64le and mips64le (dockerhub limitations may apply)
        image: rancher/mirrored-flannelcni-flannel:v0.17.0
        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: flannelcni/flannel:v0.17.0 for ppc64le and mips64le (dockerhub limitations may apply)
        image: rancher/mirrored-flannelcni-flannel:v0.17.0
        command:
        - /opt/bin/flanneld
        args:
        #- --iface=enp0s8 # 需要指定网卡,否则可能会导致问题
        - --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
        - 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

欢迎大家访问 个人博客 Johnny小屋