集群信息
节点规划
部署k8s集群的节点按照用途可以划分为如下2类角色:
- master:集群的master节点,集群的初始化节点,基础配置不低于2C4G
- slave:集群的slave节点,可以多台,基础配置不低于2C4G
本例为了演示slave节点的添加,会部署一台master+2台slave,节点规划如下:
| 主机名 | 节点ip | 角色 | 部署组件 |
|---|
| k8s-master | 172.21.51.143 | master | etcd, kube-apiserver, kube-controller-manager, kubectl, kubeadm, kubelet, kube-proxy, flannel |
| k8s-slave1 | 172.21.51.67 | slave | kubectl, kubelet, kube-proxy, flannel |
| k8s-slave2 | 172.21.51.68 | slave | kubectl, kubelet, kube-proxy, flannel |
组件版本
| 组件 | 版本 | 说明 |
|---|
| CentOS | 7.9.2009 | |
| Kernel | Linux 3.10.0-1127.10.1.el7.x86_64 | |
| etcd | 3.4.13-0 | 使用Pod方式部署,默认数据挂载到本地路径 |
| coredns | 1.7.0 | |
| kubeadm | v1.21.5 | |
| kubectl | v1.21.5 | |
| kubelet | v1.21.5 | |
| kube-proxy | v1.21.5 | |
| flannel | v0.11.0 | |
安装前准备
设置hosts解析
操作节点:所有节点(k8s-master,k8s-slave)均需执行
- 修改hostname hostname必须只能包含小写字母、数字、","、"-",且开头结尾必须是小写字母或数字
$ hostnamectl set-hostname k8s-master
$ hostnamectl set-hostname k8s-slave1
$ hostnamectl set-hostname k8s-slave2
$ cat >>/etc/hosts<<EOF
172.21.51.143 k8s-master
172.21.51.67 k8s-slave1
172.21.51.68 k8s-slave2
EOF
调整系统配置
操作节点: 所有的master和slave节点(k8s-master,k8s-slave)需要执行
本章下述操作均以k8s-master为例,其他节点均是相同的操作(ip和hostname的值换成对应机器的真实值)
如果节点间无安全组限制(内网机器间可以任意访问),可以忽略,否则,至少保证如下端口可通: k8s-master节点:TCP:6443,2379,2380,60080,60081UDP协议端口全部打开 k8s-slave节点:UDP协议端口全部打开
iptables -P FORWARD ACCEPT
swapoff -a
sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
sed -ri 's#(SELINUX=).*#\1disabled#' /etc/selinux/config
setenforce 0
systemctl disable firewalld && systemctl stop firewalld
cat <<EOF > /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward=1
vm.max_map_count=262144
EOF
modprobe br_netfilter
sysctl -p /etc/sysctl.d/k8s.conf
$ curl -o /etc/yum.repos.d/Centos-7.repo http://mirrors.aliyun.com/repo/Centos-7.repo
$ curl -o /etc/yum.repos.d/docker-ce.repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
$ cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=http://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=http://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg
http://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
$ yum clean all && yum makecache
安装docker
操作节点: 所有节点
$ yum list docker-ce --showduplicates | sort -r
$ yum install docker-ce-20.10.12 -y
$ mkdir -p /etc/docker
vi /etc/docker/daemon.json
{
"insecure-registries": [
"172.21.51.143:5000"
]
}
$ systemctl enable docker && systemctl start docker
初始化集群
安装 kubeadm, kubelet 和 kubectl
操作节点: 所有的master和slave节点(k8s-master,k8s-slave) 需要执行
$ yum install -y kubelet-1.21.5 kubeadm-1.21.5 kubectl-1.21.5 --disableexcludes=kubernetes
## 查看kubeadm 版本
$ kubeadm version
## 设置kubelet开机启动
$ systemctl enable kubelet
初始化配置文件
操作节点: 只在master节点(k8s-master)执行
$ kubeadm config print init-defaults > kubeadm.yaml
$ cat kubeadm.yaml
apiVersion: kubeadm.k8s.io/v1beta2
bootstrapTokens:
- groups:
- system:bootstrappers:kubeadm:default-node-token
token: abcdef.0123456789abcdef
ttl: 24h0m0s
usages:
- signing
- authentication
kind: InitConfiguration
localAPIEndpoint:
advertiseAddress: 172.21.51.143
bindPort: 6443
nodeRegistration:
criSocket: /var/run/dockershim.sock
name: k8s-master
taints: null
---
apiServer:
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns:
type: CoreDNS
etcd:
local:
dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: 1.21.5
networking:
dnsDomain: cluster.local
podSubnet: 10.244.0.0/16
serviceSubnet: 10.96.0.0/12
scheduler: {}
对于上面的资源清单的文档比较杂,要想完整了解上面的资源对象对应的属性,可以查看对应的 godoc 文档,地址: https://godoc.org/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta2。
提前下载镜像
操作节点:只在master节点(k8s-master)执行
$ kubeadm config images list --config kubeadm.yaml
registry.aliyuncs.com/google_containers/kube-apiserver:v1.21.5
registry.aliyuncs.com/google_containers/kube-controller-manager:v1.21.5
registry.aliyuncs.com/google_containers/kube-scheduler:v1.21.5
registry.aliyuncs.com/google_containers/kube-proxy:v1.21.5
registry.aliyuncs.com/google_containers/pause:3.4.1
registry.aliyuncs.com/google_containers/etcd:3.4.13-0
registry.aliyuncs.com/google_containers/coredns:v1.8.0
$ kubeadm config images pull --config kubeadm.yaml
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-apiserver:v1.21.5
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-controller-manager:v1.21.5
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-scheduler:v1.21.5
[config/images] Pulled registry.aliyuncs.com/google_containers/kube-proxy:v1.21.5
[config/images] Pulled registry.aliyuncs.com/google_containers/pause:3.4.1
[config/images] Pulled registry.aliyuncs.com/google_containers/etcd:3.4.13-0
[config/images] Pulled registry.aliyuncs.com/google_containers/coredns:v1.8.0
初始化master节点
操作节点:只在master节点(k8s-master)执行
$ kubeadm init --config kubeadm.yaml
若初始化成功后,最后会提示如下信息:
...
Your Kubernetes master 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 172.21.51.143:6443 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:1c4305f032f4bf534f628c32f5039084f4b103c922ff71b12a5f0f98d1ca9a4f
接下来按照上述提示信息操作,配置kubectl客户端的认证
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
**⚠️注意:**此时使用 kubectl get nodes查看节点应该处于notReady状态,因为还未配置网络插件
若执行初始化过程中出错,根据错误信息调整后,执行kubeadm reset后再次执行init操作即可
添加slave节点到集群中
操作节点:所有的slave节点(k8s-slave)需要执行 在每台slave节点,执行如下命令,该命令是在kubeadm init成功后提示信息中打印出来的,需要替换成实际init后打印出的命令。
kubeadm join 172.21.51.143:6443 --token abcdef.0123456789abcdef \
--discovery-token-ca-cert-hash sha256:1c4305f032f4bf534f628c32f5039084f4b103c922ff71b12a5f0f98d1ca9a4f
如果忘记添加命令,可以通过如下命令生成:
$ kubeadm token create --print-join-command
安装网络插件
操作节点:只在master节点(k8s-master)执行,CNI
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
- 修改配置,指定网卡名称,大概在文件的190行,添加一行配置:
$ vi kube-flannel.yml
...
containers:
- name: kube-flannel
image: rancher/mirrored-flannelcni-flannel:v0.16.1
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
- --iface=eth0 # 如果机器存在多网卡的话,指定内网网卡的名称,默认不指定的话会找第一块网卡
resources:
requests:
cpu: "100m"
...
# 先拉取镜像,此过程国内速度比较慢
$ docker pull rancher/mirrored-flannelcni-flannel:v0.16.1
# 执行flannel安装
$ kubectl apply -f kube-flannel.yml
调整证书过期
使用kubeadm安装的集群,证书默认有效期为1年,可以通过如下方式修改为10年。
$ cd /etc/kubernetes/pki
# 查看当前证书有效期
$ for i in $(ls *.crt); do echo "===== $i ====="; openssl x509 -in $i -text -noout | grep -A 3 'Validity' ; done
$ mkdir backup_key; cp -rp ./* backup_key/
$ git clone https://github.com/yuyicai/update-kube-cert.git
$ cd update-kube-cert/
$ bash update-kubeadm-cert.sh all
# 重建管理服务
$ kubectl -n kube-system delete po kube-apiserver-k8s-master kube-controller-manager-k8s-master kube-scheduler-k8s-master
验证集群
操作节点: 在master节点(k8s-master)执行
创建测试nginx服务
$ kubectl run test-nginx --image=nginx:alpine
查看pod是否创建成功,并访问pod ip测试是否可用
$ kubectl get po -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
test-nginx-5bd8859b98-5nnnw 1/1 Running 0 9s 10.244.1.2 k8s-slave1 <none> <none>
$ curl 10.244.1.2
...
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
ingress 部署
官方文档
$ wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.30.0/deploy/static/mandatory.yaml
## 或者使用myblog/deployment/ingress/mandatory.yaml
## 修改部署节点
$ grep -n5 nodeSelector mandatory.yaml
212- spec:
213- hostNetwork: true #添加为host模式
214- # wait up to five minutes for the drain of connections
215- terminationGracePeriodSeconds: 300
216- serviceAccountName: nginx-ingress-serviceaccount
217: nodeSelector:
218- ingress: "true" #替换此处,来决定将ingress部署在哪些机器
219- containers:
220- - name: nginx-ingress-controller
221- image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.30.0
222- args:
创建ingress
# 为k8s-master节点添加label
$ kubectl label node k8s-slave1 ingress=true
$ kubectl apply -f mandatory.yaml
设置kubectl自动补全
操作节点:k8s-master ,方便以后操作
$ yum install bash-completion -y
$ source /usr/share/bash-completion/bash_completion
$ source <(kubectl completion bash)
$ echo "source <(kubectl completion bash)" >> ~/.bashrc