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 +

硬件需求：CPU>=2c ,內存>=2G

環境角色

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