Centos7.9使用kubeadm部署K8S 1.27.6集群环境（内网通过代理部署）

在内网借助代理服务器，使用kubeadm部署一个k8s集群，单master+2worker节点，K8S版本为1.27.6，使用containerd作为容器运行时。

1. 环境信息

• 操作系统：CentOS 7.9.2009
• 内存: 8GB
• CPU: 4
• 网络: 节点通过代理进行访问。

hostname	ip	备注
k8s-master1	10.210.10.201	master
k8s-node1	10.210.10.202	worker
k8s-node2	10.210.10.203	worker

2. 准备工作

2.1 配置网络代理

# 配置全局代理
export proxy=http://10.0.112.18:808
export all_proxy=$proxy
export no_proxy=localhost,10.0.0.0/8,192.168.0.0/16,172.16.0.0/12

# 持久化配置可以将上面配置写/etc/profile文件

在k8s初始化的时候，容器拉取镜像需要单独配置代理：

# docker代理
[root@k8s-master1 ~]# mkdir -p /etc/systemd/system/docker.service.d
[root@k8s-master1 ~]# cat /etc/systemd/system/docker.service.d/http-proxy.conf
[Service]
Environment="HTTP_PROXY=http://10.0.112.18:808"
Environment="HTTPS_PROXY=http://10.0.112.18:808"
Environment="NO_RPOXY=localhost,127.0.0.1"

# containerd代理
[root@k8s-master1 ~]# mkdir -p /etc/systemd/system/containerd.service.d
[root@k8s-master1 ~]# cat /etc/systemd/system/containerd.service.d/http-proxy.conf
[Service]
Environment="HTTP_PROXY=http://10.0.112.18:808"
Environment="HTTPS_PROXY=http://10.0.112.18:808"
Environment="NO_RPOXY=localhost,127.0.0.1"

说明:

K8S 1.24版本后启用了docker-shim容器运行时，本地安装的k8s版本为1.27.6，选用containd作为容器运行，可以只配置containerd的代理。由于每个节点都要运行容器，所以代理需要在每个节点都需要配置。

2.2 linux基础配置

以下操作在所有节点执行：

# 配置yum源
curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo
curl -o /etc/yum.repos.d/epel.repo https://mirrors.aliyun.com/repo/epel-7.repo

# 安装常用软件
yum install wget vim-enhanced net-tools

# 关闭防火墙
systemctl stop firewalld && systemctl disable firewalld

# 关闭 swap
swapoff -a && sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab

# 关闭 selinux
setenforce 0 && sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config

设置hosts：

# 设置主机名
hostnamectl set-hostname k8s-master1  # k8s-node1 / k8s-node2
hostname

# 配置 hosts
cat >> /etc/hosts << EOF
10.210.10.201 k8s-master1
10.210.10.202 k8s-node1
10.210.10.203 k8s-node2
EOF

由于环境在内网，没有ntp服务器。这里手动修改时间，也可以配置内部的ntp服务器。

# 设置时区
timedatectl set-timezone Asia/Shanghai

# 将系统时间改为utc时间（如果需要）。编辑下面文件，写入ZONE="Etc/UTC"
vi /etc/sysconfig/clock

# 建立软连接
ln -sf /usr/share/zoneinfo/UTC /etc/localtime

# 设置系统时间为当前时间
date -s "2024-06-20 19:04:00"

# 同步硬件时间
hwclock --systohc

配置内核参数：

cat >/etc/modules-load.d/k8s.conf <<EOF
overlay
br_netfilter
EOF

modprobe overlay
modprobe br_netfilter


# 将桥接的IPv4流量传递到iptables的链
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward=1
EOF

sysctl --system  # 生效

# 通过运行以下指令确认 br_netfilter 和 overlay 模块被加载
lsmod | egrep 'overlay|br_netfilter'
# 确认sysctl配置中被设置为 1
sysctl net.bridge.bridge-nf-call-iptables net.bridge.bridge-nf-call-ip6tables net.ipv4.ip_forward

2.3 安装容器运行时

# 添加镜像源
curl https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -o /etc/yum.repos.d/docker-ce.repo

# 查看docker-ce的版本列表
yum list docker-ce --showduplicates | sort -r

# 删除 docker(如果有的话)
yum remove docker docker-client docker-client-latest docker-common docker-latest docker-latest-logrotate docker-logrotate docker-engin

# 安装必备工具
yum install -y yum-utils device-mapper-persistent-data lvm2

# 安装 docker和containerd
yum install -y docker-ce docker-ce-cli containerd.io docker-compose-plugin

# 生成并修改配置文件
cp /etc/containerd/config.toml /etc/containerd/config.toml.bak
containerd config default > /etc/containerd/config.toml
#修改
sed -i "s#registry.k8s.io/pause#registry.cn-hangzhou.aliyuncs.com/google_containers/pause#g" /etc/containerd/config.toml
sed -i "s#SystemdCgroup = false#SystemdCgroup = true#g" /etc/containerd/config.toml

# 将 containerd 加入开机自启
sudo systemctl enable --now containerd.service
# 启动 docker
sudo systemctl start docker.service
# 将 docker 加入开机自启
sudo systemctl enable docker.service
sudo systemctl enable docker.socket
sudo systemctl list-unit-files | grep docker


# 设置Docker加速
mkdir -p /etc/docker
cat > /etc/docker/daemon.json << EOF
{
  "registry-mirrors": ["https://wnsrsn9i.mirror.aliyuncs.com"],
  "exec-opts": ["native.cgroupdriver=systemd"]
}
EOF

# 重启配置生效
systemctl daemon-reload
systemctl restart docker
docker info
...
 Registry Mirrors:
  https://wnsrsn9i.mirror.aliyuncs.com/
...

2.4 安装 kubeadm、kubelet 和 kubectl

# 添加镜像源
cat > /etc/yum.repos.d/kubernetes.repo << EOF
[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
EOF

# 查看支持的版本
yum list kubelet --showduplicates | sort -r

# 安装
yum install -y kubelet-1.27.6 kubeadm-1.27.6 kubectl-1.27.6

# 配置kubelet服务自启动
systemctl enable kubelet

3. 部署k8s集群

初始化master：

# 提前拉取镜像
 kubeadm config images pull  --image-repository=registry.aliyuncs.com/google_containers

# 运行初始化命令，apiserver地址为master地址。pod网络设置为210.244.0.0/16
kubeadm init --image-repository=registry.aliyuncs.com/google_containers --kubernetes-version=v1.27.6 --apiserver-advertise-address=10.210.10.201 --pod-network-cidr=210.244.0.0/16
...
[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 10.210.10.201:6443 --token 3ravyv.7g7re8vu4xpuozmr \
        --discovery-token-ca-cert-hash sha256:cc5e30bae2b696a9d9d4535a31ed7b0dc53abe905b2ca7234336e7090f5f317a
...

# 初始化成功后，按照提示执行如下命令
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

# 查看节点列表，此时节点状态为NotReady
kubectl get nodes

初始化worker：

kubeadm join 10.210.10.201:6443 --token 3ravyv.7g7re8vu4xpuozmr \
        --discovery-token-ca-cert-hash sha256:cc5e30bae2b696a9d9d4535a31ed7b0dc53abe905b2ca7234336e7090f5f317a

master部署网络插件：

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl get pods -n kube-system  # 查看运行状态

如果无法下载，手动创建kube-flannel.yml，内容如下：

---
kind: Namespace
apiVersion: v1
metadata:
  name: kube-flannel
  labels:
    k8s-app: flannel
    pod-security.kubernetes.io/enforce: privileged
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  labels:
    k8s-app: flannel
  name: flannel
rules:
- apiGroups:
  - ""
  resources:
  - pods
  verbs:
  - get
- apiGroups:
  - ""
  resources:
  - nodes
  verbs:
  - get
  - list
  - watch
- apiGroups:
  - ""
  resources:
  - nodes/status
  verbs:
  - patch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  labels:
    k8s-app: flannel
  name: flannel
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: flannel
subjects:
- kind: ServiceAccount
  name: flannel
  namespace: kube-flannel
---
apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-app: flannel
  name: flannel
  namespace: kube-flannel
---
kind: ConfigMap
apiVersion: v1
metadata:
  name: kube-flannel-cfg
  namespace: kube-flannel
  labels:
    tier: node
    k8s-app: flannel
    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",
      "EnableNFTables": false,
      "Backend": {
        "Type": "vxlan"
      }
    }
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: kube-flannel-ds
  namespace: kube-flannel
  labels:
    tier: node
    app: flannel
    k8s-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: docker.io/flannel/flannel-cni-plugin:v1.4.1-flannel1
        command:
        - cp
        args:
        - -f
        - /flannel
        - /opt/cni/bin/flannel
        volumeMounts:
        - name: cni-plugin
          mountPath: /opt/cni/bin
      - name: install-cni
        image: docker.io/flannel/flannel:v0.25.4
        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: docker.io/flannel/flannel:v0.25.4
        command:
        - /opt/bin/flanneld
        args:
        - --ip-masq
        - --kube-subnet-mgr
        resources:
          requests:
            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

说明：

flannel.yaml中的"Network"指定的ip地址与kubeadm init初始化时指定的pod网络保持一致。

部署flannel会拉取两个镜像，国内网络环境有时候无法顺利拉取，可以从其他地方获取后离线导入当前环境：

[root@k8s-master1 ~]# docker images
REPOSITORY                              TAG               IMAGE ID       CREATED        SIZE
flannel/flannel                         v0.25.4           e6c43605b714   18 hours ago   81MB
flannel/flannel-cni-plugin              v1.4.1-flannel1   1e3c860c213d   7 weeks ago    10.3MB

说明：

本次安装容器同时安装了docker和containerd，但是k8s底层对接的是containerd，kubeadm初始化时会走containerd拉取镜像，所以网络代理要配置到containerd一侧。另外containerd底层有命名空间的概念，如果容器镜像采用离线导入的方式，需要指定命名空间，参考命令ctr -n=k8s.io images import xxx.tar