使用kubeadm安裝k8s-1.11版本多主高可用

實驗環境說明

實驗架構圖

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
複製代碼

實驗使用的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 複製代碼

安裝配置docker

v1.11.0版本推薦使用docker v17.03, v1.11,v1.12,v1.13, 也可以使用，再高版本的docker可能無法正常使用。 測試發現17.09無法正常使用，不能使用資源限制(內存CPU)

如下操作在所有節點操作

安裝docker

# 卸載安裝指定版本docker-ce
yum remove -y docker-ce docker-ce-selinux container-selinux
yum install -y --setopt=obsoletes=0 \
docker-ce-17.03.1.ce-1.el7.centos \
docker-ce-selinux-17.03.1.ce-1.el7.centos
複製代碼

啓動docker

systemctl enable docker && systemctl restart docker
複製代碼

安裝 kubeadm, kubelet 和 kubectl

如下操作在所有節點操作

使用阿里鏡像安裝

# 配置源
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

# 安裝
yum install -y kubelet kubeadm kubectl ipvsadm
複製代碼

配置系統相關參數

# 臨時禁用selinux # 永久關閉 修改/etc/sysconfig/selinux文件設置
sed -i 's/SELINUX=permissive/SELINUX=disabled/' /etc/sysconfig/selinux
setenforce 0

# 臨時關閉swap # 永久關閉 註釋/etc/fstab文件裏swap相關的行
swapoff -a # 開啓forward # Docker從1.13版本開始調整了默認的防火牆規則 # 禁用了iptables filter表中FOWARD鏈 # 這樣會引起Kubernetes集羣中跨Node的Pod無法通信

iptables -P FORWARD ACCEPT

# 配置轉發相關參數，否則可能會出錯
cat <<EOF > /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
vm.swappiness=0
EOF
sysctl --system

# 加載ipvs相關內核模塊 # 如果重新開機，需要重新加載
modprobe ip_vs
modprobe ip_vs_rr
modprobe ip_vs_wrr
modprobe ip_vs_sh
modprobe nf_conntrack_ipv4
lsmod | grep ip_vs
複製代碼

配置hosts解析

如下操作在所有節點操作

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
複製代碼

配置haproxy代理和keepalived

如下操作在節點lab1,lab2,lab3操作

# 拉取haproxy鏡像
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

# 啓動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

# 查看日誌
docker logs my-haproxy

# 瀏覽器查看狀態
http://11.11.11.111:1080/haproxy-status
http://11.11.11.112:1080/haproxy-status

# 拉取keepalived鏡像
docker pull osixia/keepalived:1.4.4

# 啓動 # 載入內核相關模塊
lsmod | grep ip_vs
modprobe ip_vs

# 啓動keepalived # eth1爲本次實驗11.11.11.0/24網段的所在網卡
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

# 查看日誌 # 會看到兩個成爲backup 一個成爲master
docker logs k8s-keepalived

# 此時會配置 11.11.11.110 到其中一臺機器 # ping測試
ping -c4 11.11.11.110

# 如果失敗後清理後，重新實驗
docker rm -f k8s-keepalived
ip a del 11.11.11.110/32 dev eth1
複製代碼

配置啓動kubelet

如下操作在所有節點操作

# 配置kubelet使用國內pause鏡像 # 配置kubelet的cgroups # 獲取docker的cgroups
DOCKER_CGROUPS=$(docker info | grep 'Cgroup' | cut -d' ' -f3)
echo $DOCKER_CGROUPS
cat >/etc/sysconfig/kubelet<<EOF
KUBELET_EXTRA_ARGS="--cgroup-driver=$DOCKER_CGROUPS --pod-infra-container-image=registry.cn-hangzhou.aliyuncs.com/google_containers/pause-amd64:3.1"
EOF

# 啓動
systemctl daemon-reload
systemctl enable kubelet && systemctl restart kubelet
複製代碼

配置master

配置第一個master節點

如下操作在lab1節點操作

# 1.11 版本 centos 下使用 ipvs 模式會出問題 # 參考 https://github.com/kubernetes/kubernetes/issues/65461 # 生成配置文件
CP0_IP="11.11.11.111"
CP0_HOSTNAME="lab1"
cat >kubeadm-master.config<<EOF
apiVersion: kubeadm.k8s.io/v1alpha2
kind: MasterConfiguration
kubernetesVersion: v1.11.0
imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers

apiServerCertSANs:
- "lab1"
- "lab2"
- "lab3"
- "11.11.11.111"
- "11.11.11.112"
- "11.11.11.113"
- "11.11.11.110"
- "127.0.0.1"

api:
 advertiseAddress: $CP0_IP
 controlPlaneEndpoint: 11.11.11.110:8443

etcd:
 local:
 extraArgs:
 listen-client-urls: "https://127.0.0.1:2379,https://$CP0_IP:2379"
 advertise-client-urls: "https://$CP0_IP:2379"
 listen-peer-urls: "https://$CP0_IP:2380"
 initial-advertise-peer-urls: "https://$CP0_IP:2380"
 initial-cluster: "$CP0_HOSTNAME=https://$CP0_IP:2380"
 serverCertSANs:
 - $CP0_HOSTNAME
 - $CP0_IP
 peerCertSANs:
 - $CP0_HOSTNAME
 - $CP0_IP

controllerManagerExtraArgs:
 node-monitor-grace-period: 10s
 pod-eviction-timeout: 10s

networking:
 podSubnet: 10.244.0.0/16
 
kubeProxy:
 config:
 # mode: ipvs
 mode: iptables
EOF

# 提前拉取鏡像 # 如果執行失敗 可以多次執行
kubeadm config images pull --config kubeadm-master.config

# 初始化 # 注意保存返回的 join 命令
kubeadm init --config kubeadm-master.config

# 打包ca相關文件上傳至其他master節點 cd /etc/kubernetes && tar cvzf k8s-key.tgz admin.conf pki/ca.* pki/sa.* pki/front-proxy-ca.* pki/etcd/ca.*
scp k8s-key.tgz lab2:~/
scp k8s-key.tgz lab3:~/
ssh lab2 'tar xf k8s-key.tgz -C /etc/kubernetes/'
ssh lab3 'tar xf k8s-key.tgz -C /etc/kubernetes/' 複製代碼

配置第二個master節點

如下操作在lab2節點操作

# 1.11 版本 centos 下使用 ipvs 模式會出問題 # 參考 https://github.com/kubernetes/kubernetes/issues/65461 # 生成配置文件
CP0_IP="11.11.11.111"
CP0_HOSTNAME="lab1"
CP1_IP="11.11.11.112"
CP1_HOSTNAME="lab2"
cat >kubeadm-master.config<<EOF
apiVersion: kubeadm.k8s.io/v1alpha2
kind: MasterConfiguration
kubernetesVersion: v1.11.0
imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers

apiServerCertSANs:
- "lab1"
- "lab2"
- "lab3"
- "11.11.11.111"
- "11.11.11.112"
- "11.11.11.113"
- "11.11.11.110"
- "127.0.0.1"

api:
 advertiseAddress: $CP1_IP
 controlPlaneEndpoint: 11.11.11.110:8443

etcd:
 local:
 extraArgs:
 listen-client-urls: "https://127.0.0.1:2379,https://$CP1_IP:2379"
 advertise-client-urls: "https://$CP1_IP:2379"
 listen-peer-urls: "https://$CP1_IP:2380"
 initial-advertise-peer-urls: "https://$CP1_IP:2380"
 initial-cluster: "$CP0_HOSTNAME=https://$CP0_IP:2380,$CP1_HOSTNAME=https://$CP1_IP:2380"
 initial-cluster-state: existing
 serverCertSANs:
 - $CP1_HOSTNAME
 - $CP1_IP
 peerCertSANs:
 - $CP1_HOSTNAME
 - $CP1_IP

controllerManagerExtraArgs:
 node-monitor-grace-period: 10s
 pod-eviction-timeout: 10s

networking:
 podSubnet: 10.244.0.0/16
 
kubeProxy:
 config:
 # mode: ipvs
 mode: iptables
EOF

# 配置kubelet
kubeadm alpha phase certs all --config kubeadm-master.config
kubeadm alpha phase kubelet config write-to-disk --config kubeadm-master.config
kubeadm alpha phase kubelet write-env-file --config kubeadm-master.config
kubeadm alpha phase kubeconfig kubelet --config kubeadm-master.config
systemctl restart kubelet

# 添加etcd到集羣中
CP0_IP="11.11.11.111"
CP0_HOSTNAME="lab1"
CP1_IP="11.11.11.112"
CP1_HOSTNAME="lab2"
KUBECONFIG=/etc/kubernetes/admin.conf kubectl exec -n kube-system etcd-${CP0_HOSTNAME} -- etcdctl --ca-file /etc/kubernetes/pki/etcd/ca.crt --cert-file /etc/kubernetes/pki/etcd/peer.crt --key-file /etc/kubernetes/pki/etcd/peer.key --endpoints=https://${CP0_IP}:2379 member add ${CP1_HOSTNAME} https://${CP1_IP}:2380
kubeadm alpha phase etcd local --config kubeadm-master.config

# 提前拉取鏡像 # 如果執行失敗 可以多次執行
kubeadm config images pull --config kubeadm-master.config

# 部署
kubeadm alpha phase kubeconfig all --config kubeadm-master.config
kubeadm alpha phase controlplane all --config kubeadm-master.config
kubeadm alpha phase mark-master --config kubeadm-master.config
複製代碼

配置第三個master節點

如下操作在lab3節點操作

# 1.11 版本 centos 下使用 ipvs 模式會出問題 # 參考 https://github.com/kubernetes/kubernetes/issues/65461 # 生成配置文件
CP0_IP="11.11.11.111"
CP0_HOSTNAME="lab1"
CP1_IP="11.11.11.112"
CP1_HOSTNAME="lab2"
CP2_IP="11.11.11.113"
CP2_HOSTNAME="lab3"
cat >kubeadm-master.config<<EOF
apiVersion: kubeadm.k8s.io/v1alpha2
kind: MasterConfiguration
kubernetesVersion: v1.11.0
imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers

apiServerCertSANs:
- "lab1"
- "lab2"
- "lab3"
- "11.11.11.111"
- "11.11.11.112"
- "11.11.11.113"
- "11.11.11.110"
- "127.0.0.1"

api:
 advertiseAddress: $CP2_IP
 controlPlaneEndpoint: 11.11.11.110:8443

etcd:
 local:
 extraArgs:
 listen-client-urls: "https://127.0.0.1:2379,https://$CP2_IP:2379"
 advertise-client-urls: "https://$CP2_IP:2379"
 listen-peer-urls: "https://$CP2_IP:2380"
 initial-advertise-peer-urls: "https://$CP2_IP:2380"
 initial-cluster: "$CP0_HOSTNAME=https://$CP0_IP:2380,$CP1_HOSTNAME=https://$CP1_IP:2380,$CP2_HOSTNAME=https://$CP2_IP:2380"
 initial-cluster-state: existing
 serverCertSANs:
 - $CP2_HOSTNAME
 - $CP2_IP
 peerCertSANs:
 - $CP2_HOSTNAME
 - $CP2_IP

controllerManagerExtraArgs:
 node-monitor-grace-period: 10s
 pod-eviction-timeout: 10s

networking:
 podSubnet: 10.244.0.0/16
 
kubeProxy:
 config:
 # mode: ipvs
 mode: iptables
EOF

# 配置kubelet
kubeadm alpha phase certs all --config kubeadm-master.config
kubeadm alpha phase kubelet config write-to-disk --config kubeadm-master.config
kubeadm alpha phase kubelet write-env-file --config kubeadm-master.config
kubeadm alpha phase kubeconfig kubelet --config kubeadm-master.config
systemctl restart kubelet

# 添加etcd到集羣中
CP0_IP="11.11.11.111"
CP0_HOSTNAME="lab1"
CP2_IP="11.11.11.113"
CP2_HOSTNAME="lab3"
KUBECONFIG=/etc/kubernetes/admin.conf kubectl exec -n kube-system etcd-${CP0_HOSTNAME} -- etcdctl --ca-file /etc/kubernetes/pki/etcd/ca.crt --cert-file /etc/kubernetes/pki/etcd/peer.crt --key-file /etc/kubernetes/pki/etcd/peer.key --endpoints=https://${CP0_IP}:2379 member add ${CP2_HOSTNAME} https://${CP2_IP}:2380
kubeadm alpha phase etcd local --config kubeadm-master.config

# 提前拉取鏡像 # 如果執行失敗 可以多次執行
kubeadm config images pull --config kubeadm-master.config

# 部署
kubeadm alpha phase kubeconfig all --config kubeadm-master.config
kubeadm alpha phase controlplane all --config kubeadm-master.config
kubeadm alpha phase mark-master --config kubeadm-master.config
複製代碼

配置使用kubectl

如下操作在任意master節點操作

rm -rf $HOME/.kube
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node節點
kubectl get nodes

# 只有網絡插件也安裝配置完成之後，才能會顯示爲ready狀態 # 設置master允許部署應用pod，參與工作負載，現在可以部署其他系統組件 # 如 dashboard, heapster, efk等
kubectl taint nodes --all node-role.kubernetes.io/master-

複製代碼

配置使用網絡插件

如下操作在任意master節點操作

# 下載配置
mkdir flannel && cd flannel
wget https://raw.githubusercontent.com/coreos/flannel/v0.10.0/Documentation/kube-flannel.yml

# 修改配置 # 此處的ip配置要與上面kubeadm的pod-network一致
 net-conf.json: |
 {
 "Network": "10.244.0.0/16",
 "Backend": {
 "Type": "vxlan"
 }
 }

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

# 如果Node有多個網卡的話，參考flannel issues 39701， # https://github.com/kubernetes/kubernetes/issues/39701 # 目前需要在kube-flannel.yml中使用--iface參數指定集羣主機內網網卡的名稱， # 否則可能會出現dns無法解析。容器無法通信的情況，需要將kube-flannel.yml下載到本地， # flanneld啓動參數加上--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

# 啓動
kubectl apply -f kube-flannel.yml

# 查看
kubectl get pods --namespace kube-system
kubectl get svc --namespace kube-system
複製代碼

配置node節點加入集羣

如下操作在所有node節點操作

# 此命令爲初始化master成功後返回的結果
kubeadm join 11.11.11.110:8443 --token yzb7v7.dy40mhlljt1d48i9 --discovery-token-ca-cert-hash sha256:61ec309e6f942305006e6622dcadedcc64420e361231eff23cb535a183c0e77a
複製代碼

基礎測試

測試容器間的通信和DNS

配置好網絡之後，kubeadm會自動部署coredns

如下測試可以在配置kubectl的節點上操作

啓動

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
複製代碼

查看狀態

kubectl get deploy
kubectl get pods
kubectl get svc
kubectl describe svc example-service
複製代碼

DNS解析

kubectl run curl --image=radial/busyboxplus:curl -i --tty
nslookup kubernetes
nslookup example-service
curl example-service
複製代碼

訪問測試

# 10.96.59.56 爲查看svc時獲取到的clusterip
curl "10.96.59.56:80" # 32223 爲查看svc時獲取到的 nodeport
http://11.11.11.112:32223/
http://11.11.11.113:32223/
複製代碼

清理刪除

kubectl delete svc example-service example-service-nodeport
kubectl delete deploy nginx curl
複製代碼

高可用測試

關閉任一master節點測試集羣是能否正常執行上一步的基礎測試，查看相關信息，不能同時關閉兩個節點，因爲3個節點組成的etcd集羣，最多只能有一個當機。

# 查看組件狀態
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

# 訪問測試
CURL_POD=$(kubectl get pods | grep curl | grep Running | cut -d ' ' -f1)
kubectl exec -ti $CURL_POD -- sh --tty
nslookup kubernetes
nslookup example-service
curl example-service
複製代碼

小技巧

忘記初始master節點時的node節點加入集羣命令怎麼辦

# 簡單方法
kubeadm token create --print-join-command

# 第二種方法
token=$(kubeadm token generate)
kubeadm token create $token --print-join-command --ttl=0

本文轉自掘金-使用kubeadm安裝k8s-1.11版本多主高可用