4.2 集群部署 - kubeadm

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2023-12-01

Kubernetes 一键部署脚本（使用 docker 运行时）

# on master
git clone https://github.com/feiskyer/ops
cd ops
kubernetes/install-kubernetes.sh
# 记住控制台输出的 TOEKN 和 MASTER 地址，在其他 Node 安装时会用到
# on node
git clone https://github.com/feiskyer/ops
cd ops
export TOKEN=xxxxx
export MASTER_IP=xx.xx.xx.xx
kubernetes/add-docker-node.sh

以下是详细的安装步骤。

初始化系统

所有机器都需要初始化 docker 和 kubelet。

ubuntu

# for ubuntu 16.04+
apt-get update && apt-get install -y apt-transport-https
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
cat <<EOF> /etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF
apt-get update
# Install docker if you don't have it already.
apt-get install -y docker.io
apt-get install -y kubelet kubeadm kubectl kubernetes-cni
systemctl enable docker && systemctl start docker
systemctl enable kubelet

centos

cat <<EOF> /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://yum.kubernetes.io/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
       https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF
setenforce 0
yum install -y docker kubelet kubeadm kubectl kubernetes-cni
systemctl enable docker && systemctl start docker
systemctl enable kubelet

国内用户也可以使用阿里云的镜像来安装

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=0
EOF

安装 master

# --api-advertise-addresses <ip-address>
# for flannel, setup --pod-network-cidr 10.244.0.0/16
kubeadm init --pod-network-cidr 10.244.0.0/16 --kubernetes-version latest
# enable schedule pods on the master
export KUBECONFIG=/etc/kubernetes/admin.conf
# for v1.5-, use kubectl taint nodes --all dedicated-
kubectl taint nodes --all node-role.kubernetes.io/master:NoSchedule-

如果需要修改 kubernetes 服务的配置选项，则需要创建一个 MasterConfiguration 配置文件，其格式为

apiVersion: kubeadm.k8s.io/v1alpha1
kind: MasterConfiguration
api:
  advertiseAddress: <address|string>
  bindPort: <int>
etcd:
  endpoints:
  - <endpoint1|string>
  - <endpoint2|string>
  caFile: <path|string>
  certFile: <path|string>
  keyFile: <path|string>
networking:
  dnsDomain: <string>
  serviceSubnet: <cidr>
  podSubnet: <cidr>
kubernetesVersion: <string>
cloudProvider: <string>
authorizationModes:
- <authorizationMode1|string>
- <authorizationMode2|string>
token: <string>
tokenTTL: <time duration>
selfHosted: <bool>
apiServerExtraArgs:
  <argument>: <value|string>
  <argument>: <value|string>
controllerManagerExtraArgs:
  <argument>: <value|string>
  <argument>: <value|string>
schedulerExtraArgs:
  <argument>: <value|string>
  <argument>: <value|string>
apiServerCertSANs:
- <name1|string>
- <name2|string>
certificatesDir: <string>

比如

# cat kubeadm.yml
kind: MasterConfiguration
apiVersion: kubeadm.k8s.io/v1alpha1
kubernetesVersion: "stable"
apiServerCertSANs: []
controllerManagerExtraArgs:
  horizontal-pod-autoscaler-use-rest-clients: "true"
  horizontal-pod-autoscaler-sync-period: "10s"
  node-monitor-grace-period: "10s"
  feature-gates: "AllAlpha=true"
  enable-dynamic-provisioning: "true"
apiServerExtraArgs:
  runtime-config: "api/all=true"
  feature-gates: "AllAlpha=true"
networking:
  podSubnet: "10.244.0.0/16"

然后，在初始化 master 的时候指定 kubeadm.yml 的路径：

kubeadm init --config ./kubeadm.yaml

配置 Network plugin

CNI bridge

mkdir -p /etc/cni/net.d
cat >/etc/cni/net.d/10-mynet.conf <<-EOF
{
    "cniVersion": "0.3.0",
    "name": "mynet",
    "type": "bridge",
    "bridge": "cni0",
    "isGateway": true,
    "ipMasq": true,
    "ipam": {
        "type": "host-local",
        "subnet": "10.244.0.0/16",
        "routes": [
            {"dst": "0.0.0.0/0"}
        ]
    }
}
EOF
cat >/etc/cni/net.d/99-loopback.conf <<-EOF
{
    "cniVersion": "0.3.0",
    "type": "loopback"
}
EOF

flannel

注意：需要 kubeadm init 时设置 --pod-network-cidr=10.244.0.0/16

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.9.1/Documentation/kube-flannel.yml

weave

kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d'n')"

calico

注意：需要 kubeadm init 时设置 --pod-network-cidr=192.168.0.0/16

kubectl apply -f https://docs.projectcalico.org/v3.0/getting-started/kubernetes/installation/hosted/kubeadm/1.7/calico.yaml

添加 Node

token=$(kubeadm token list | grep authentication,signing | awk '{print $1}')
kubeadm join --token $token ${master_ip}

跟 Master 一样，添加 Node 的时候也可以自定义 Kubernetes 服务的选项，格式为

apiVersion: kubeadm.k8s.io/v1alpha1
kind: NodeConfiguration
caCertPath: <path|string>
discoveryFile: <path|string>
discoveryToken: <string>
discoveryTokenAPIServers:
- <address|string>
- <address|string>
tlsBootstrapToken: <string>

在把 Node 加入集群的时候，指定 NodeConfiguration 配置文件的路径

kubeadm join --config ./nodeconfig.yml --token $token ${master_ip}

删除安装

kubeadm reset

动态升级

kubeadm v1.8 开始支持动态升级，升级步骤为

首先上传 kubeadm 配置，如 kubeadm config upload from-flags [flags]（使用命令行参数）或 kubeadm config upload from-file --config [config]（使用配置文件）
在 master 上检查新版本 kubeadm upgrade plan，当有新版本（如 v1.8.0）时，执行 kubeadm upgrade apply v1.8.0 升级控制平面
手动升级 CNI 插件（如果有新版本的话）
添加自动证书回滚的 RBAC 策略 kubectl create clusterrolebinding kubeadm:node-autoapprove-certificate-rotation --clusterrole=system:certificates.k8s.io:certificatesigningrequests:selfnodeclient --group=system:nodes
最后升级 kubelet

$ kubectl drain $HOST --ignore-daemonsets
# 升级软件包
$ apt-get update
$ apt-get upgrade
# CentOS 上面执行 yum 升级
# $ yum update
$ kubectl uncordon $HOST

手动升级

kubeadm v1.7 以及以前的版本不支持动态升级，但可以手动升级。

升级 Master

假设你已经有一个使用 kubeadm 部署的 Kubernetes v1.6 集群，那么升级到 v1.7 的方法为：

升级安装包 apt-get upgrade && apt-get update
重启 kubelet systemctl restart kubelet
删除 kube-proxy DaemonSet KUBECONFIG=/etc/kubernetes/admin.conf kubectl delete daemonset kube-proxy -n kube-system
kubeadm init —skip-preflight-checks —kubernetes-version v1.7.1
更新 CNI 插件

升级 Node

升级安装包 apt-get upgrade && apt-get update
重启 kubelet systemctl restart kubelet

安全选项

默认情况下，kubeadm 会开启 Node 客户端证书的自动批准，如果不需要的话可以选择关闭，关闭方法为

$ kubectl delete clusterrole kubeadm:node-autoapprove-bootstrap

关闭后，增加新的 Node 时，kubeadm join 会阻塞等待管理员手动批准，匹配方法为

$ kubectl get csr
NAME                                                   AGE       REQUESTOR                 CONDITION
node-csr-c69HXe7aYcqkS1bKmH4faEnHAWxn6i2bHZ2mD04jZyQ   18s       system:bootstrap:878f07   Pending
$ kubectl certificate approve node-csr-c69HXe7aYcqkS1bKmH4faEnHAWxn6i2bHZ2mD04jZyQ
certificatesigningrequest "node-csr-c69HXe7aYcqkS1bKmH4faEnHAWxn6i2bHZ2mD04jZyQ" approved
$ kubectl get csr
NAME                                                   AGE       REQUESTOR                 CONDITION
node-csr-c69HXe7aYcqkS1bKmH4faEnHAWxn6i2bHZ2mD04jZyQ   1m        system:bootstrap:878f07   Approved,Issued