centos7使用kubeadm配置高可用k8s集群

时间：2022-06-01 20:48:49
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2018.08.12 09:06* 字数 464 阅读 88评论 0喜欢 0

简介

使用kubeadm配置多master节点，实现高可用。

安装

实验环境说明

实验架构图
lab1: etcd master haproxy keepalived 11.11.11.111

lab2: etcd master haproxy keepalived 11.11.11.112

lab3: etcd master haproxy keepalived 11.11.11.113

lab4: node  11.11.11.114

lab5: node  11.11.11.115

lab6: node  11.11.11.116

vip(loadblancer ip): 11.11.11.110
实验使用的Vagrantfile 
# -*- mode: ruby -*-

# vi: set ft=ruby :

ENV["LC_ALL"] = "en_US.UTF-8"

Vagrant.configure("2") do |config|

    (1..6).each do |i|

      config.vm.define "lab#{i}" do |node|

        node.vm.box = "centos-7.4-docker-17"

        node.ssh.insert_key = false

        node.vm.hostname = "lab#{i}"

        node.vm.network "private_network", ip: "11.11.11.11#{i}"

        node.vm.provision "shell",

          inline: "echo hello from node #{i}"

        node.vm.provider "virtualbox" do |v|

          v.cpus = 2

          v.customize ["modifyvm", :id, "--name", "lab#{i}", "--memory", "2048"]

        end

      end

    end

end

在所有机器上安装kubeadm

参考之前的文章《centos7安装kubeadm》

配置所有节点的kubelet

# 配置kubelet使用国内可用镜像

# 修改/etc/systemd/system/kubelet.service.d/10-kubeadm.conf

# 添加如下配置

Environment="KUBELET_EXTRA_ARGS=--pod-infra-container-image=registry.cn-shanghai.aliyuncs.com/gcr-k8s/pause-amd64:3.0"

# 使用命令

sed -i '/ExecStart=$/i Environment="KUBELET_EXTRA_ARGS=--pod-infra-container-image=registry.cn-shanghai.aliyuncs.com/gcr-k8s/pause-amd64:3.0"'  /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

# 重新载入配置

systemctl daemon-reload

配置所有节点的hosts

cat >>/etc/hosts<<EOF

11.11.11.111 lab1

11.11.11.112 lab2

11.11.11.113 lab3

11.11.11.114 lab4

11.11.11.115 lab5

11.11.11.116 lab6

EOF

启动etcd集群

在lab1,lab2,lab3节点上启动etcd集群

# lab1

docker stop etcd && docker rm etcd

rm -rf /data/etcd

mkdir -p /data/etcd

docker run -d \

--restart always \

-v /etc/etcd/ssl/certs:/etc/ssl/certs \

-v /data/etcd:/var/lib/etcd \

-p 2380:2380 \

-p 2379:2379 \

--name etcd \

registry.cn-hangzhou.aliyuncs.com/google_containers/etcd-amd64:3.1.12 \

etcd --name=etcd0 \

--advertise-client-urls=http://11.11.11.111:2379 \

--listen-client-urls=http://0.0.0.0:2379 \

--initial-advertise-peer-urls=http://11.11.11.111:2380 \

--listen-peer-urls=http://0.0.0.0:2380 \

--initial-cluster-token=9477af68bbee1b9ae037d6fd9e7efefd \

--initial-cluster=etcd0=http://11.11.11.111:2380,etcd1=http://11.11.11.112:2380,etcd2=http://11.11.11.113:2380 \

--initial-cluster-state=new \

--auto-tls \

--peer-auto-tls \

--data-dir=/var/lib/etcd

# lab2

docker stop etcd && docker rm etcd

rm -rf /data/etcd

mkdir -p /data/etcd

docker run -d \

--restart always \

-v /etc/etcd/ssl/certs:/etc/ssl/certs \

-v /data/etcd:/var/lib/etcd \

-p 2380:2380 \

-p 2379:2379 \

--name etcd \

registry.cn-hangzhou.aliyuncs.com/google_containers/etcd-amd64:3.1.12 \

etcd --name=etcd1 \

--advertise-client-urls=http://11.11.11.112:2379 \

--listen-client-urls=http://0.0.0.0:2379 \

--initial-advertise-peer-urls=http://11.11.11.112:2380 \

--listen-peer-urls=http://0.0.0.0:2380 \

--initial-cluster-token=9477af68bbee1b9ae037d6fd9e7efefd \

--initial-cluster=etcd0=http://11.11.11.111:2380,etcd1=http://11.11.11.112:2380,etcd2=http://11.11.11.113:2380 \

--initial-cluster-state=new \

--auto-tls \

--peer-auto-tls \

--data-dir=/var/lib/etcd

# lab3

docker stop etcd && docker rm etcd

rm -rf /data/etcd

mkdir -p /data/etcd

docker run -d \

--restart always \

-v /etc/etcd/ssl/certs:/etc/ssl/certs \

-v /data/etcd:/var/lib/etcd \

-p 2380:2380 \

-p 2379:2379 \

--name etcd \

registry.cn-hangzhou.aliyuncs.com/google_containers/etcd-amd64:3.1.12 \

etcd --name=etcd2 \

--advertise-client-urls=http://11.11.11.113:2379 \

--listen-client-urls=http://0.0.0.0:2379 \

--initial-advertise-peer-urls=http://11.11.11.113:2380 \

--listen-peer-urls=http://0.0.0.0:2380 \

--initial-cluster-token=9477af68bbee1b9ae037d6fd9e7efefd \

--initial-cluster=etcd0=http://11.11.11.111:2380,etcd1=http://11.11.11.112:2380,etcd2=http://11.11.11.113:2380 \

--initial-cluster-state=new \

--auto-tls \

--peer-auto-tls \

--data-dir=/var/lib/etcd

# 验证查看集群

docker exec -ti etcd ash

etcdctl member list

etcdctl cluster-health

exit

在第一台master节点初始化

# 生成token

# 保留token后面还要使用

token=$(kubeadm token generate)

echo $token

# 生成配置文件

cat >kubeadm-master.config<<EOF

apiVersion: kubeadm.k8s.io/v1alpha1

kind: MasterConfiguration

kubernetesVersion: v1.10.1

#imageRepository: registry.cn-shanghai.aliyuncs.com/gcr-k8s

imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers

api:

  advertiseAddress: 11.11.11.111

apiServerExtraArgs:

  endpoint-reconciler-type: lease

controllerManagerExtraArgs:

  node-monitor-grace-period: 10s

  pod-eviction-timeout: 10s

networking:

  podSubnet: 192.168.0.0/16

etcd:

  endpoints:

  - "http://11.11.11.111:2379"

  - "http://11.11.11.112:2379"

  - "http://11.11.11.113:2379"

apiServerCertSANs:

- "lab1"

- "lab2"

- "lab3"

- "11.11.11.111"

- "11.11.11.112"

- "11.11.11.113"

- "11.11.11.110"

- "127.0.0.1"

token: $token

tokenTTL: "0"

featureGates:

  CoreDNS: true

EOF

# 初始化

kubeadm init --config kubeadm-master.config

systemctl enable kubelet

# 保存初始化完成之后的join命令

# 如果丢失可以使用命令"kubeadm token list"获取

# kubeadm join 11.11.11.111:6443 --token nevmjk.iuh214fc8i0k3iue --discovery-token-ca-cert-hash sha256:0e4f738348be836ff810bce754e059054845f44f01619a37b817eba83282d80f

# 配置kubectl使用

mkdir -p $HOME/.kube

sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

sudo chown $(id -u):$(id -g) $HOME/.kube/config

# 安装网络插件

# 下载配置

mkdir flannel && cd flannel

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

# 修改配置

# 此处的ip配置要与上面kubeadm的pod-network一致

  net-conf.json: |

    {

      "Network": "192.168.0.0/16",

      "Backend": {

        "Type": "vxlan"

      }

    }

# 修改镜像

image: registry.cn-shanghai.aliyuncs.com/gcr-k8s/flannel:v0.10.0-amd64

# 启动

kubectl apply -f kube-flannel.yml

# 如果Node有多个网卡的话，参考flannel issues 39701，

# https://github.com/kubernetes/kubernetes/issues/39701

# 目前需要在kube-flannel.yml中使用--iface参数指定集群主机内网网卡的名称，

# 否则可能会出现dns无法解析。容器无法通信的情况，需要将kube-flannel.yml下载到本地，

# flanneld启动参数加上--iface=<iface-name>

    containers:

      - name: kube-flannel

        image: registry.cn-shanghai.aliyuncs.com/gcr-k8s/flannel:v0.10.0-amd64

        command:

        - /opt/bin/flanneld

        args:

        - --ip-masq

        - --kube-subnet-mgr

        - --iface=eth1

# 查看

kubectl get pods --namespace kube-system

kubectl get svc --namespace kube-system

# 设置master允许部署应用pod，参与工作负载，现在可以部署其他系统组件

# 如 dashboard, heapster, efk等

kubectl taint nodes --all node-role.kubernetes.io/master-

启动其他master节点

# 打包第一台master初始化之后的/etc/kubernetes/pki目录

cd /etc/kubernetes && tar czvf /root/pki.tgz pki/ && cd ~

# 上传到其他master的/etc/kubernetes目录下

tar xf pki.tgz -C /etc/kubernetes/

# 删除pki目录下的apiserver.crt 和 apiserver.key文件

rm -rf /etc/kubernetes/pki/{apiserver.crt,apiserver.key}

# 生成配置文件

# 使用和之前master一样的配置文件

# token保持一致

cat >kubeadm-master.config<<EOF

apiVersion: kubeadm.k8s.io/v1alpha1

kind: MasterConfiguration

kubernetesVersion: v1.10.1

#imageRepository: registry.cn-shanghai.aliyuncs.com/gcr-k8s

imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers

# 注意修改IP

api:

  advertiseAddress: 11.11.11.112

apiServerExtraArgs:

  endpoint-reconciler-type: lease

controllerManagerExtraArgs:

  node-monitor-grace-period: 10s

  pod-eviction-timeout: 10s

networking:

  podSubnet: 192.168.0.0/16

etcd:

  endpoints:

  - "http://11.11.11.111:2379"

  - "http://11.11.11.112:2379"

  - "http://11.11.11.113:2379"

apiServerCertSANs:

- lab1

- lab2

- lab3

- "11.11.11.111"

- "11.11.11.112"

- "11.11.11.113"

- "11.11.11.110"

- "127.0.0.1"

token: nevmjk.iuh214fc8i0k3iue

tokenTTL: "0"

featureGates:

  CoreDNS: true

EOF

# 初始化

kubeadm init --config kubeadm-master.config

systemctl enable kubelet

# 查看状态

kubectl get pod --all-namespaces -o wide | grep lab1

kubectl get pod --all-namespaces -o wide | grep lab2

kubectl get pod --all-namespaces -o wide | grep lab3

kubectl get nodes -o wide

配置haproxy代理和keepalived

在lab1,lab2,lab3节点上启动haproxy和keepalived

# 拉取haproxy镜像

docker pull haproxy:1.7.8-alpine

mkdir /etc/haproxy

cat >/etc/haproxy/haproxy.cfg<<EOF

global

  log 127.0.0.1 local0 err

  maxconn 50000

  uid 99

  gid 99

  #daemon

  nbproc 1

  pidfile haproxy.pid

defaults

  mode http

  log 127.0.0.1 local0 err

  maxconn 50000

  retries 3

  timeout connect 5s

  timeout client 30s

  timeout server 30s

  timeout check 2s

listen admin_stats

  mode http

  bind 0.0.0.0:1080

  log 127.0.0.1 local0 err

  stats refresh 30s

  stats uri     /haproxy-status

  stats realm   Haproxy\ Statistics

  stats auth    will:will

  stats hide-version

  stats admin if TRUE

frontend k8s-https

  bind 0.0.0.0:8443

  mode tcp

  #maxconn 50000

  default_backend k8s-https

backend k8s-https

  mode tcp

  balance roundrobin

  server lab1 11.11.11.111:6443 weight 1 maxconn 1000 check inter 2000 rise 2 fall 3

  server lab2 11.11.11.112:6443 weight 1 maxconn 1000 check inter 2000 rise 2 fall 3

  server lab3 11.11.11.113:6443 weight 1 maxconn 1000 check inter 2000 rise 2 fall 3

EOF

# 启动haproxy

docker run -d --name my-haproxy \

-v /etc/haproxy:/usr/local/etc/haproxy:ro \

-p 8443:8443 \

-p 1080:1080 \

--restart always \

haproxy:1.7.8-alpine

# 查看日志

docker logs my-haproxy

# 浏览器查看状态

http://11.11.11.111:1080/haproxy-status

http://11.11.11.112:1080/haproxy-status

# 拉取keepalived镜像

docker pull osixia/keepalived:1.4.4

# 启动

# 载入内核相关模块

lsmod | grep ip_vs

modprobe ip_vs

# 启动keepalived

# eth1为本次实验11.11.11.0/24网段的所在网卡

docker run --net=host --cap-add=NET_ADMIN \

-e KEEPALIVED_INTERFACE=eth1 \

-e KEEPALIVED_VIRTUAL_IPS="#PYTHON2BASH:['11.11.11.110']" \

-e KEEPALIVED_UNICAST_PEERS="#PYTHON2BASH:['11.11.11.111','11.11.11.112','11.11.11.113']" \

-e KEEPALIVED_PASSWORD=hello \

--name k8s-keepalived \

--restart always \

-d osixia/keepalived:1.4.4

# 查看日志

# 会看到两个成为backup 一个成为master

docker logs k8s-keepalived

# 此时会配置 11.11.11.110 到其中一台机器

# ping测试

ping -c4 11.11.11.110

# 如果失败后清理后，重新实验

docker rm -f k8s-keepalived

ip a del 11.11.11.110/32 dev eth1

# 修改~/.kube/config文件里ip和端口，然后使用kubectl测试

rm -rf .kube/cache .kube/http-cache

kubectl get pods -n kube-system -o wide

修改master节点相关组件配置指向vip

# lab1 lab2 lab3

sed -i 's@server: https://11.11.11.*:6443@server: https://11.11.11.110:8443@g' /etc/kubernetes/{admin.conf,kubelet.conf,scheduler.conf,controller-manager.conf}

# 重启kubelet

systemctl daemon-reload

systemctl restart kubelet docker

# 查看所有节点状态

kubectl get nodes -o wide

修改kube-proxy的配置

# 修改kube-proxy的配置指定vip

# 执行命令之后修改为 server: https://11.11.11.110:8443

kubectl edit -n kube-system configmap/kube-proxy

# 查看设置

kubectl get -n kube-system configmap/kube-proxy -o yaml

# 删除重建kube-proxy

kubectl get pods --all-namespaces -o wide | grep proxy

all_proxy_pods=$(kubectl get pods --all-namespaces -o wide | grep proxy | awk '{print $2}' | xargs)

echo $all_proxy_pods

kubectl delete pods $all_proxy_pods -n kube-system

kubectl get pods --all-namespaces -o wide | grep proxy

启动node节点

# 加入master节点

# 这个命令是之前初始化master完成时，输出的命令

kubeadm join 11.11.11.110:8443 --token nevmjk.iuh214fc8i0k3iue --discovery-token-ca-cert-hash sha256:0e4f738348be836ff810bce754e059054845f44f01619a37b817eba83282d80f

systemctl enable kubelet

修改node节点kubelet配置并重启

# 修改配置

sed -i 's@server: https://11.11.11.*:6443@server: https://11.11.11.110:8443@g' /etc/kubernetes/kubelet.conf

# 重启kubelet

systemctl daemon-reload

systemctl restart kubelet docker

# 查看所有节点状态

kubectl get nodes -o wide

禁止master节点发布应用

设置master不接受负载

# 查看状态

kubectl get nodes

# 设置

# kubectl patch node lab1 -p '{"spec":{"unschedulable":true}}'

kubectl taint nodes lab1 lab2 lab3 node-role.kubernetes.io/master=true:NoSchedule

# 查看状态

kubectl get nodes

测试

重建多个coredns副本

# 删除coredns的pods

kubectl get pods -n kube-system -o wide | grep coredns

all_coredns_pods=$(kubectl get pods -n kube-system -o wide | grep coredns | awk '{print $1}' | xargs)

echo $all_coredns_pods

kubectl delete pods $all_coredns_pods -n kube-system

# 修改副本数

# replicas: 3

# 可以修改为node节点的个数

kubectl edit deploy coredns -n kube-system

# 查看状态

kubectl get pods -n kube-system -o wide | grep coredns

基础测试

1. 启动

# 直接使用命令测试

kubectl run nginx --replicas=2 --image=nginx:alpine --port=80

kubectl expose deployment nginx --type=NodePort --name=example-service-nodeport

kubectl expose deployment nginx --name=example-service

# 使用配置文件测试

cat >example-nginx.yml<<EOF

apiVersion: extensions/v1beta1

kind: Deployment

metadata:

  name: nginx

spec:

  replicas: 2

  template:

    metadata:

      labels:

        app: nginx

    spec:

      restartPolicy: Always

      containers:

      - name: nginx

        image: nginx:alpine

        ports:

        - containerPort: 80

        livenessProbe:

          httpGet:

            path: /

            port: 80

          initialDelaySeconds: 10

          periodSeconds: 3

        readinessProbe:

          httpGet:

            path: /

            port: 80

          initialDelaySeconds: 10

          periodSeconds: 3

---

kind: Service

apiVersion: v1

metadata:

  name: example-service

spec:

    selector:

      app: nginx

    ports:

      - name: http

        port: 80

        targetPort: 80

---

kind: Service

apiVersion: v1

metadata:

  name: example-service-nodeport

spec:

    selector:

      app: nginx

    type: NodePort

    ports:

      - name: http-nodeport

        port: 80

        nodePort: 32223

EOF

kubectl apply -f example-nginx.yml

2. 查看状态

kubectl get deploy

kubectl get pods

kubectl get svc

kubectl describe svc example-service

3. DNS解析

kubectl run curl --image=radial/busyboxplus:curl -i --tty

nslookup kubernetes

nslookup example-service

curl example-service

# 如果时间过长会返回错误，可以使用如下方式再进入测试

curlPod=$(kubectl get pod | grep curl | awk '{print $1}')

kubectl exec -ti $curlPod -- sh

4. 访问测试

# 10.96.59.56 为查看svc时获取到的clusterip

curl "10.96.59.56:80"

# 32223 为查看svc时获取到的 nodeport

http://11.11.11.114:32223/

http://11.11.11.115:32223/

3. 清理删除

kubectl delete svc example-service example-service-nodeport

kubectl delete deploy nginx curl

高可用测试

关闭master节点测试集群是能否正常执行上一步的基础测试，查看相关信息，不能同时关闭lab1和lab2，因为上面有haproxy和keepalived服务

kubectl get pod --all-namespaces -o wide

kubectl get pod --all-namespaces -o wide | grep lab1

kubectl get pod --all-namespaces -o wide | grep lab2

kubectl get pod --all-namespaces -o wide | grep lab3

kubectl get nodes -o wide

kubectl get deploy

kubectl get pods

kubectl get svc

kubectl describe svc example-service

注意事项

  • 当直接把node节点关闭时，只有过了5分钟之后，上面的pod才会被检测到有问题，并迁移到其他节点

如果想快速迁移可以执行 kubectl delete node

也可以修改controller-manager的的pod-eviction-timeout参数，默认5m

node-monitor-grace-period参数，默认40s

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