Kubernetes集群组件介绍
Master组件
- kube-apiserver
- Kubernetes API, 集群的统一入口,各组件协调者,以RESTful API提供接口服务,所有对象资源的增删改查和监听操作都交给APIServer处理后再提交给Etcd存储。
- kube-controller-manager
- 处理集群中常规后台任务,一个资源对应一个控制器,而ControllerManager就是负责管理这些控制器的。
- kube-scheduler
- 根据调度算法为新创建的Pod选择一个Node节点,可以任意部署,可以部署在同一个节点上,也可以部署在不同的节点上。
- etcd
- 分布式键值存储系统。用于保存集群状态数据,比如Pod、Service等对象信息。
Node组件
- kubelet
- kubelet是Master在Node节点上的Agent,管理本机运行容器的生命周期,比如创建容器、Pod挂载数据卷、下载secret、获取容器和节点状态等工作。kubelet将每个Pod转换成一组容器。
- kube-proxy
- 在Node节点上实现Pod网络代理,维护网络规则和四层负载均衡工作。
- docker或rocket
- 容器引擎,运行容器。
Kubernetes 核心概念
- Pod
- 最小部署单元
- 一组容器的集合
- 一个Pod中的容器共享网络命名空间
- Pod是短暂的
- Controllers
- ReplicaSet :确保预期的Pod副本数量
- Deployment :无状态应用部署
- StatefulSet :有状态应用部署
- DaemonSet :确保所有Node运行同一个Pod
- Job :一次性任务
- Cronjob :定时任务
更高级层次对象,部署和管理Pod
- Service
- 防止Pod失联
- 定义一组Pod的访问策略
- Label :标签,附加到某个资源上,用于关联对象、查询和筛选
- Namespaces:命名空间,将对象逻辑上隔离
- Annotations :注释
kubernetes 官方提供的三种部署方式
- minikube
Minikube是一个工具,可以在本地快速运行一个单点的Kubernetes,仅用于尝试Kubernetes或日常开发的用户使用。部署地址:https://kubernetes.io/docs/setup/minikube/
- kubeadm
Kubeadm也是一个工具,提供kubeadm init和kubeadm join,用于快速部署Kubernetes集群。部署地址:https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm/
- 二进制包
推荐,从官方下载发行版的二进制包,手动部署每个组件,组成Kubernetes集群。下载地址:https://github.com/kubernetes/kubernetes/releases
安装kubeadm环境准备
以下操作在三节点都执行
环境需求
环境:centos 7.4 +
硬件需求:CPU>=2c ,内存>=2G
配置base源、epel源
环境角色
IP | 角色 | 安装软件 |
---|---|---|
10.4.7.106 | k8s-Master | kube-apiserver kube-schduler kube-controller-manager docker flannel kubelet |
10.4.7.107 | k8s-node01 | kubelet kube-proxy docker flannel |
10.4.7.108 | k8s-node01 | kubelet kube-proxy docker flannel |
环境初始化
1、关闭防火墙、selinux
关闭防火墙:
systemctl stop firewalld
systemctl disable firewalld
关闭selinux
永久关闭命令:
sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config
grep SELINUX=disabled /etc/selinux/config
临时关闭命令:
setenforce 0
getenforce
2、关闭swap分区
swapoff -a # 临时
sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab #永久
3、分别在每台机器配置主机名和hosts解析
10.4.7.106 master
10.4.7.107 node1
10.4.7.108 node2
4、内核调整,将桥接的IPv4流量传递到iptables的链
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF
sysctl --system
5、设置系统时区并同步时间服务器
yum install -y ntpdate
ntpdate time.windows.com
6、docker安装
yum install -y yum-utils device-mapper-persistent-data lvm2
yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
yum makecache fast
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
7、添加kubernetes YUM软件源
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
setenforce 0
yum install -y kubelet-1.15.0 kubeadm-1.15.0 kubectl-1.15.0
systemctl enable kubelet
8、配置docker并重启
vim /etc/docker/daemon.json
{
"registry-mirrors": ["https://tghecaz8.mirror.aliyuncs.com"],
"exec-opts": ["native.cgroupdriver=systemd"]
}
9、部署Kubernetes Master
kubeadm init --apiserver-advertise-address=10.4.7.103 --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
10、根据输出提示操作
[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
加入Kubernetes Node
在两个node节点执行
使用kubeadm join 注册Node节点到Matser
kubeadm join 的内容,在上面kubeadm init 已经生成好了
安装网络插件
只在master执行
wget https://raw.githubusercontent.com/coreos/flannel/a70459be0084506e4ec919aa1c114638878db11b/Documentation/kube-flannel.yml
kubectl apply -f kube-flannel.yml
查看进程
ps -ef|grep flannel
查看集群node状态
查看集群的node状态,安装完网络工具之后,只有显示如下状态,所有节点全部都Ready好了之后才能继续后面的操作
kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master Ready master 37m v1.15.0
k8s-node01 Ready <none> 5m22s v1.15.0
k8s-node02 Ready <none> 5m18s v1.15.0
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
只有全部都为1/1则可以成功执行后续步骤,如果flannel需检查网络情况,重新进行如下操作
测试Kubernetes集群
在Kubernetes集群中创建一个pod,然后暴露端口,验证是否正常访问:
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 <none> 443/TCP 39m
service/nginx NodePort 10.1.224.251 <none> 80:32039/TCP 9s
访问地址:http://NodeIP:Port
部署 Dashboard
wget https://raw.githubusercontent.com/kubernetes/dashboard/v1.10.1/src/deploy/recommended/kubernetes-dashboard.yaml
vim kubernetes-dashboard.yaml
修改内容:
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
kubectl apply -f kubernetes-dashboard.yaml
访问地址: https://NodeIP:30001
创建service account并绑定默认cluster-admin管理员集群角色:
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}')
Name: dashboard-admin-token-zbn9f
Namespace: kube-system
Labels: <none>
Annotations: kubernetes.io/service-account.name: dashboard-admin
kubernetes.io/service-account.uid: 40259d83-3b4f-4acc-a4fb-43018de7fc19
Type: kubernetes.io/service-account-token
Data
====
namespace: 11 bytes
token: eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.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.E0hGAkeQxd6K-YpPgJmNTv7Sn_P_nzhgCnYXGc9AeXd9k9qAcO97vBeOV-pH518YbjrOAx_D6CKIyP07aCi_3NoPlbbyHtcpRKFl-lWDPdg8wpcIefcpbtS6uCOrpaJdCJjWFcAEHdvcfmiFpdVVT7tUZ2-eHpRTUQ5MDPF-c2IOa9_FC9V3bf6XW6MSCZ_7-fOF4MnfYRa8ucltEIhIhCAeDyxlopSaA5oEbopjaNiVeJUGrKBll8Edatc7-wauUIJXAN-dZRD0xTULPNJ1BsBthGQLyFe8OpL5n_oiHM40tISJYU_uQRlMP83SfkOpbiOpzuDT59BBJB57OQtl3w
ca.crt: 1025 bytes
解决其他浏览器不能访问的问题
[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 #回到这个yaml的路径下修改
修改 dashboard-controller.yaml 文件,在args下面增加证书两行
- --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}')
Name: dashboard-admin-token-zbn9f
Namespace: kube-system
Labels: <none>
Annotations: kubernetes.io/service-account.name: dashboard-admin
kubernetes.io/service-account.uid: 40259d83-3b4f-4acc-a4fb-43018de7fc19
Type: kubernetes.io/service-account-token
Data
====
namespace: 11 bytes
token: eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.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.E0hGAkeQxd6K-YpPgJmNTv7Sn_P_nzhgCnYXGc9AeXd9k9qAcO97vBeOV-pH518YbjrOAx_D6CKIyP07aCi_3NoPlbbyHtcpRKFl-lWDPdg8wpcIefcpbtS6uCOrpaJdCJjWFcAEHdvcfmiFpdVVT7tUZ2-eHpRTUQ5MDPF-c2IOa9_FC9V3bf6XW6MSCZ_7-fOF4MnfYRa8ucltEIhIhCAeDyxlopSaA5oEbopjaNiVeJUGrKBll8Edatc7-wauUIJXAN-dZRD0xTULPNJ1BsBthGQLyFe8OpL5n_oiHM40tISJYU_uQRlMP83SfkOpbiOpzuDT59BBJB57OQtl3w
ca.crt: 1025 bytes
kubeadm配置集群的node节点执行kubectl命令
1、拷贝master的节点的admin.conf
2、在node节点执行
mkdir -p $HOME/.kube
执行cp -i PATH/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
3、已经可以执行kubectl命令