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k8s是什么意思？
kubernetes簡稱K8s，是一個開源的，用于管理云平臺中多個主機上的容器化的應用，Kubernetes的目標是讓部署容器化的應用簡單并且高效（powerful）,Kubernetes提供了應用部署，規劃，更新，維護的一種機制。
在Kubernetes中，我們可以創建多個容器，每個容器里面運行一個應用實例，然后通過內置的負載均衡策略，實現對這一組應用實例的管理、發現、訪問，而這些細節都不需要運維人員去進行復雜的手工配置和處理。
kubernetes（K8s）特點：
可移植: 支持公有云，私有云，混合云，多重云（multi-cloud）
可擴展: 模塊化，插件化，可掛載，可組合
自動化: 自動部署，自動重啟，自動復制，自動伸縮/擴展
kubeadm部署k8s集群（k8s部署）：
kubernetes（k8s）三種部署方式
minikube
Minikube是一種可以在本地快速運行單點Kubernetes的工具，僅用于嘗試Kubernetes或日常開發的用戶。
kubeadm
Kubeadm也是提供kubeadm的工具 init和kubeadm join，用于快速部署Kubernetes集群。
二進制包推薦，從官方下載發行版的二進制包，手動部署每個組件，形成Kubernetes集群。
安裝kubeadm環境準備
以下操作,在三臺節點都執行
2.2.1 環境需求
環境：centos 7.4 +
環境角色
| IP | 角色 | 安裝軟件 |
|---|---|---|
| 10.0.0.100 | k8s-Master | kube-apiserver kube-schduler kube-controller-manager docker flannel kubelet |
| 10.0.0.101 | k8s-node01 | kubelet kube-proxy docker flannel |
| 10.0.0.102 | k8s-node02 | kubelet kube-proxy docker flannel |
1、關閉防火墻及selinux
systemctl stop firewalld && systemctl disable firewalld
sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config && setenforce 0
2、關閉 swap 分區
swapoff -a # 臨時
sed -i '/ swap / s/^(.*)$/#1/g' /etc/fstab #永久
3、分別在10.0.0.100、10.0.0.101、10.0.0.102上設置主機名及配置hosts
hostnamectl set-hostname k8s-master
hostnamectl set-hostname k8s-node01
hostnamectl set-hostname k8s-node02
4、在所有主機上上添加如下命令
cat >> /etc/hosts << EOF
10.0.0.100 k8s-master
10.0.0.101 k8s-node01
10.0.0.102 k8s-node02
EOF
5、內核調整,將橋接的IPv4流量傳遞到iptables的鏈
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system
6、設置系統時區并同步時間服務器
yum install -y ntpdate
ntpdate time.windows.com
2.2.4 docker 安裝
wget https://06)">mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
yum -y install docker-ce-18.06.1.ce-3.el7
systemctl enable docker && systemctl start docker
docker --version
Docker version 18.06.1-ce, build e68fc7a
2.2.5 添加kubernetes YUM軟件源
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
2.2.6 安裝kubeadm,kubelet和kubectl
2.2.6上所有主機都需要操作
yum install -y kubelet-1.15.0 kubeadm-1.15.0 kubectl-1.15.0
systemctl enable kubelet
如果遇到下面情況
清除yum 緩存，然后再執行安裝命令
yum clean all
如果還不行，則直接安裝最新版的
yum makecache fast
yum install -y kubelet kubeadm kubectl
2.3 部署Kubernetes Master
只需要在Master 節點執行，這里的apiserve需要修改成自己的master地址
[root@k8s-master ~]#
kubeadm init
--apiserver-advertise-address=10.0.0.100
--image-repository registry.aliyuncs.com/google_containers
--kubernetes-version v1.15.0
--service-cidr=10.1.0.0/16
--pod-network-cidr=10.244.0.0/16
由于默認拉取鏡像地址k8s.gcr.io國內無法訪問，這里指定阿里云鏡像倉庫地址。
輸出結果則為成功:
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 10.0.0.100:6443 --token fylid0.3udi31k2aw9zvjtc
--discovery-token-ca-cert-hash sha256:3fbb4b58eccff32668473b99cc3b0c64964f1363c93d7c6a8f502d43d34718d3
根據輸出提示操作：
[root@k8s-master ~]# mkdir -p $HOME/.kube
[root@k8s-master ~]# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
[root@k8s-master ~]# sudo chown (id -u):(id -g) $HOME/.kube/config
重新生成新的token（初次不執行）
默認token的有效期為24小時，當過期之后，該token就不可用了，
如果后續有nodes節點加入，解決方法如下：
重新生成新的token
kubeadm token create
[root@k8s-master ~]# kubeadm token create
0w3a92.ijgba9ia0e3scicg
[root@k8s-master ~]# kubeadm token list
TOKEN TTL EXPIRES USAGES DESCRIPTION EXTRA GROUPS
0w3a92.ijgba9ia0e3scicg 23h 2019-09-08T22:02:40+08:00 authentication,signing system:bootstrappers:kubeadm:default-node-token
t0ehj8.k4ef3gq0icr3etl0 22h 2019-09-08T20:58:34+08:00 authentication,signing The default bootstrap token generated by 'kubeadm init'. system:bootstrappers:kubeadm:default-node-token
[root@k8s-master ~]#
獲取ca證書sha256編碼hash值
[root@k8s-master ~]# openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'
ce07a7f5b259961884c55e3ff8784b1eda6f8b5931e6fa2ab0b30b6a4234c09a
節點加入集群
[root@k8s-node01 ~]# kubeadm join --token aa78f6.8b4cafc8ed26c34f --discovery-token-ca-cert-hash sha256:0fd95a9bc67a7bf0ef42da968a0d55d92e52898ec37c971bd77ee501d845b538 10.0.0.100:6443 --skip-preflight-chec
2.4 加入Kubernetes Node
在兩個Node 節點執行
使用kubeadm join 注冊Node節點到Matser
kubeadm join 的內容，在上面kubeadm init 已經生成好了
[root@k8s-node01 ~]# kubeadm join 10.0.0.100:6443 --token fylid0.3udi31k2aw9zvjtc
--discovery-token-ca-cert-hash sha256:3fbb4b58eccff32668473b99cc3b0c64964f1363c93d7c6a8f502d43d34718d3
輸出內容則為成功：
[preflight] Running pre-flight checks
[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.15" ConfigMap in the kube-system namespace
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Activating the kubelet service
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
This node has joined the cluster:
- Certificate signing request was sent to apiserver and a response was received.
- The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
2.5 安裝網絡插件
只需要在Master 節點執行
[root@k8s-master ~]# wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
修改鏡像地址：(有可能默認不能拉取，確保能夠訪問到quay.io這個registery,否則修改如下內容)
[root@k8s-master ~]# vim kube-flannel.yml
進入編輯，把106行，120行的內容，替換如下image，替換之后查看如下為正確
[root@k8s-master ~]# cat -n kube-flannel.yml|grep lizhenliang/flannel:v0.11.0-amd64
172 image: lizhenliang/flannel:v0.11.0-amd64
186 image: lizhenliang/flannel:v0.11.0-amd64
[root@k8s-master ~]# kubectl apply -f kube-flannel.yml
[root@k8s-master ~]# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-bccdc95cf-b9pz7 1/1 Running 0 10m
coredns-bccdc95cf-dfb58 1/1 Running 0 10m
etcd-k8s-master 1/1 Running 0 9m47s
kube-apiserver-k8s-master 1/1 Running 0 9m49s
kube-controller-manager-k8s-master 1/1 Running 0 9m46s
kube-flannel-ds-amd64-5lqjb 1/1 Running 0 2m6s
kube-flannel-ds-amd64-jvvpx 0/1 Init:0/1 0 2m6s
kube-proxy-hjwzg 1/1 Running 0 10m
kube-proxy-rxm2g 1/1 Running 0 6m51s
kube-scheduler-k8s-master 1/1 Running 0 9m41s
2.6 查看集群node狀態
查看集群的node狀態，安裝完網絡工具之后，只有顯示如下狀態，所有節點全部都Ready好了之后才能繼續后面的操作
[root@k8s-master ~]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master Ready master 37m v1.15.0
k8s-node01 Ready 5m22s v1.15.0
k8s-node02 Ready 5m18s v1.15.0
[root@k8s-node01 ~]# kubectl get pod -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-bccdc95cf-6pdgv 1/1 Running 0 80m
coredns-bccdc95cf-f845x 1/1 Running 0 80m
etcd-k8s-master 1/1 Running 0 80m
kube-apiserver-k8s-master 1/1 Running 0 79m
kube-controller-manager-k8s-master 1/1 Running 0 80m
kube-flannel-ds-amd64-chpz8 1/1 Running 0 70m
kube-flannel-ds-amd64-jx56v 1/1 Running 0 70m
kube-flannel-ds-amd64-tsgvv 1/1 Running 0 70m
kube-proxy-d5b7l 1/1 Running 0 80m
kube-proxy-f7v46 1/1 Running 0 75m
kube-proxy-wqhsj 1/1 Running 0 78m
kube-scheduler-k8s-master 1/1 Running 0 80m
kubernetes-dashboard-8499f49758-6f6ct 1/1 Running 0 42m
只有全部都為1/1則可以成功執行后續步驟，如果flannel需檢查網絡情況，重新進行如下操作
kubectl delete -f kube-flannel.yml
然后重新wget，然后修改鏡像地址，然后
kubectl apply -f kube-flannel.yml
2.7 創建一個nignx
在Kubernetes集群中創建一個pod，然后暴露端口，驗證是否正常訪問：
[root@k8s-master ~]# kubectl create deployment nginx --image=nginx
deployment.apps/nginx created
[root@k8s-master ~]# kubectl expose deployment nginx --port=80 --type=NodePort
service/nginx exposed
[root@k8s-master ~]# kubectl get pods,svc
NAME READY STATUS RESTARTS AGE
pod/nginx-554b9c67f9-wf5lm 1/1 Running 0 24s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.1.0.1 443/TCP 39m
service/nginx NodePort 10.1.224.251 80:32039/TCP 9s
訪問地址：http://NodeIP:Port ,此例就是：http://10.0.0.101:32039
2.8 部署 Dashboard
[root@k8s-master ~]# wget https://raw.githubusercontent.com/kubernetes/dashboard/v1.10.1/src/deploy/recommended/kubernetes-dashboard.yaml
[root@k8s-master ~]# vim kubernetes-dashboard.yaml
修改內容：
109 spec:
110 containers:
111 - name: kubernetes-dashboard
112 image: lizhenliang/kubernetes-dashboard-amd64:v1.10.1 # 修改此行
......
157 spec:
158 type: NodePort # 增加此行
159 ports:
160 - port: 443
161 targetPort: 8443
162 nodePort: 30001 # 增加此行
163 selector:
164 k8s-app: kubernetes-dashboard
[root@k8s-master ~]# kubectl apply -f kubernetes-dashboard.yaml
[root@k8s-master ~]# kubectl get pod -n kube-system
[root@k8s-master ~]# kubectl get pods,svc -n kube-system
在火狐瀏覽器訪問(google受信任問題不能訪問)地址： https://10.0.0.101:30001
創建service account并綁定默認cluster-admin管理員集群角色：
[root@k8s-master ~]# kubectl create serviceaccount dashboard-admin -n kube-system
[root@k8s-master ~]# kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin
[root@k8s-master ~]# kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')
2.9 解決其他瀏覽器不能訪問的問題
[root@k8s-master ~]# cd /etc/kubernetes/pki/
[root@k8s-master pki]# mkdir ui
[root@k8s-master pki]# cp apiserver.crt ui/
[root@k8s-master pki]# cp apiserver.key ui/
[root@k8s-master pki]# cd ui/
[root@k8s-master ui]# mv apiserver.crt dashboard.pem
[root@k8s-master ui]# mv apiserver.key dashboard-key.pem
[root@k8s-master ui]# kubectl delete secret kubernetes-dashboard-certs -n kube-system
[root@k8s-master ui]# kubectl create secret generic kubernetes-dashboard-certs --from-file=./ -n kube-system
[root@k8s-master]# vim kubernetes-dashboard.yaml
#回到這個yaml的路徑下修改
修改dashboard-controller.yaml 文件，在args下面增加證書兩行
- --tls-key-file=dashboard-key.pem
- --tls-cert-file=dashboard.pem
[root@k8s-master ~]kubectl apply -f kubernetes-dashboard.yaml
[root@k8s-master ~]# kubectl create serviceaccount dashboard-admin -n kube-system
serviceaccount/dashboard-admin created
[root@k8s-master ~]# kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin
--serviceaccount=kube-system:dashboard-admin
[root@k8s-master ~]# kubectl describe secrets -n kube-system $(kubectl -n kube-system get secret | awk '/dashboard-admin/{print $1}')
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審核編輯 黃宇
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