K8s深入了解
Ingress控制器介绍
1.没有ingress之前，pod对外提供服务只能通过NodeIP:NodePort的形式，但是这种形式有缺点，一个节点上的PORT不能重复利用。比如某个服务占用了80，那么其他服务就不能在用这个端口了。
2.NodePort是4层代理，不能解析7层的http，不能通过域名区分流量
3.为了解决这个问题，我们需要用到资源控制器叫Ingress，作用就是提供一个统一的访问入口。工作在7层
4.虽然我们可以使用nginx/haproxy来实现类似的效果，但是传统部署不能动态的发现我们新创建的资源，必须手动修改配置文件并重启。
5.适用于k8s的ingress控制器主流的有ingress-nginx和traefik
6.ingress-nginx == nginx + go --> deployment部署
7.traefik有一个UI界面
安装部署traefik
1.traefik_dp.yaml
kind: Deployment
apiVersion: apps/v1
metadata:
name: traefik-ingress-controller
namespace: kube-system
labels:
k8s-app: traefik-ingress-lb
spec:
replicas: 1
selector:
matchLabels:
k8s-app: traefik-ingress-lb
template:
metadata:
labels:
k8s-app: traefik-ingress-lb
name: traefik-ingress-lb
spec:
serviceAccountName: traefik-ingress-controller
terminationGracePeriodSeconds: 60
tolerations:
- operator: "Exists"
nodeSelector:
kubernetes.io/hostname: node1
containers:
- image: traefik:v1.7.17
name: traefik-ingress-lb
ports:
- name: http
containerPort: 80
hostPort: 80
- name: admin
containerPort: 8080
args:
- --api
- --kubernetes
- --logLevel=INFO
2.traefik_rbac.yaml
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: traefik-ingress-controller
namespace: kube-system
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: traefik-ingress-controller
rules:
- apiGroups:
- ""
resources:
- services
- endpoints
- secrets
verbs:
- get
- list
- watch
- apiGroups:
- extensions
resources:
- ingresses
verbs:
- get
- list
- watch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: traefik-ingress-controller
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: traefik-ingress-controller
subjects:
- kind: ServiceAccount
name: traefik-ingress-controller
namespace: kube-system
3.traefik_svc.yaml
kind: Service
apiVersion: v1
metadata:
name: traefik-ingress-service
namespace: kube-system
spec:
selector:
k8s-app: traefik-ingress-lb
ports:
- protocol: TCP
port: 80
name: web
- protocol: TCP
port: 8080
name: admin
type: NodePort
4.应用资源配置
kubectl create -f ./
5.查看并访问
kubectl -n kube-system get svc
创建traefik的web-ui的ingress规则
1.类比nginx:
upstream traefik-ui {
server traefik-ingress-service:8080;
}
server {
location / {
proxy_pass http://traefik-ui;
include proxy_params;
}
}
2.ingress写法:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: traefik-ui
namespace: kube-system
spec:
rules:
- host: traefik.ui.com
http:
paths:
- path: /
backend:
serviceName: traefik-ingress-service
servicePort: 8080
3.访问测试：
traefik.ui.com
ingress实验
1.实验目标
未使用ingress之前只能通过IP+端口访问：
tomcat 8080
nginx 8090
使用ingress之后直接可以使用域名访问：
traefik.nginx.com:80 --> nginx 8090
traefik.tomcat.com:80 --> tomcat 8080
2.创建2个pod和svc
mysql-dp.yaml
mysql-svc.yaml
tomcat-dp.yaml
tomcat-svc.yaml
nginx-dp.yaml
nginx-svc-clusterip.yaml
3.创建ingress控制器资源配置清单并应用
cat >nginx-ingress.yaml <<EOF
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: traefik-nginx
namespace: default
spec:
rules:
- host: traefik.nginx.com
http:
paths:
- path: /
backend:
serviceName: nginx-service
servicePort: 80
EOF
cat >tomcat-ingress.yaml<<EOF
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: traefik-tomcat
namespace: default
spec:
rules:
- host: traefik.tomcat.com
http:
paths:
- path: /
backend:
serviceName: myweb
servicePort: 8080
EOF
kubectl apply -f nginx-ingress.yaml
kubectl apply -f tomcat-ingress.yaml
4.查看创建的资源
kubectl get svc
kubectl get ingresses
kubectl describe ingresses traefik-nginx
kubectl describe ingresses traefik-tomcat
5.访问测试
traefik.nginx.com
traefik.tomcat.com
数据持久化
Volume介绍
Volume是Pad中能够被多个容器访问的共享目录
Kubernetes中的Volume不Pad生命周期相同，但不容器的生命周期丌相关
Kubernetes支持多种类型的Volume，并且一个Pod可以同时使用任意多个Volume
Volume类型包括:
- EmptyDir：Pod分配时创建， K8S自动分配，当Pod被移除数据被清空。用于临时空间等。
- hostPath：为Pod上挂载宿主机目录。用于持久化数据。
- nfs：挂载相应磁盘资源。
EmptyDir实验
cat >emptyDir.yaml <<EOF
apiVersion: v1
kind: Pod
metadata:
name: busybox-empty
spec:
containers:
- name: busybox-pod
image: busybox
volumeMounts:
- mountPath: /data/busybox/
name: cache-volume
command: ["/bin/sh","-c","while true;do echo $(date) >> /data/busybox/index.html;sleep 3;done"]
volumes:
- name: cache-volume
emptyDir: {}
EOF
hostPath实验
1.发现的问题：
- 目录必须存在才能创建
- POD不固定会创建在哪个Node上，数据不统一
2.type类型说明
https://kubernetes.io/docs/concepts/storage/volumes/#hostpath
DirectoryOrCreate 目录不存在就自动创建
Directory 目录必须存在
FileOrCreate 文件不存在则创建
File 文件必须存在
3.根据Node标签选择POD创建在指定的Node上
方法1: 直接选择Node节点名称
apiVersion: v1
kind: Pod
metadata:
name: busybox-nodename
spec:
nodeName: node2
containers:
- name: busybox-pod
image: busybox
volumeMounts:
- mountPath: /data/pod/
name: hostpath-volume
command: ["/bin/sh","-c","while true;do echo $(date) >> /data/pod/index.html;sleep 3;done"]
volumes:
- name: hostpath-volume
hostPath:
path: /data/node/
type: DirectoryOrCreate
方法2: 根据Node标签选择Node节点
kubectl label nodes node3 disktype=SSD
apiVersion: v1
kind: Pod
metadata:
name: busybox-nodename
spec:
nodeSelector:
disktype: SSD
containers:
- name: busybox-pod
image: busybox
volumeMounts:
- mountPath: /data/pod/
name: hostpath-volume
command: ["/bin/sh","-c","while true;do echo $(date) >> /data/pod/index.html;sleep 3;done"]
volumes:
- name: hostpath-volume
hostPath:
path: /data/node/
type: DirectoryOrCreate
4.实验-编写mysql的持久化deployment
apiVersion: apps/v1
kind: Deployment
metadata:
name: mysql-dp
namespace: default
spec:
selector:
matchLabels:
app: mysql
replicas: 1
template:
metadata:
name: mysql-pod
namespace: default
labels:
app: mysql
spec:
containers:
- name: mysql-pod
image: mysql:5.7
ports:
- name: mysql-port
containerPort: 3306
env:
- name: MYSQL_ROOT_PASSWORD
value: "123456"
volumeMounts:
- mountPath: /var/lib/mysql
name: mysql-volume
volumes:
- name: mysql-volume
hostPath:
path: /data/mysql
type: DirectoryOrCreate
nodeSelector:
disktype: SSD
PV和PVC
1.master节点安装nfs
yum install nfs-utils -y
mkdir /data/nfs-volume -p
vim /etc/exports
/data/nfs-volume 10.0.0.0/24(rw,async,no_root_squash,no_all_squash)
systemctl start rpcbind
systemctl start nfs
showmount -e 127.0.0.1
2.所有node节点安装nfs
yum install nfs-utils.x86_64 -y
showmount -e 10.0.0.11
3.编写并创建nfs-pv资源
cat >nfs-pv.yaml <<EOF
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv01
spec:
capacity:
storage: 5Gi
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Recycle
storageClassName: nfs
nfs:
path: /data/nfs-volume/mysql
server: 10.0.0.11
EOF
kubectl create -f nfs-pv.yaml
kubectl get persistentvolume
3.创建mysql-pvc
cat >mysql-pvc.yaml <<EOF
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: mysql-pvc
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
storageClassName: nfs
EOF
kubectl create -f mysql-pvc.yaml
kubectl get pvc
4.创建mysql-deployment
cat >mysql-dp.yaml <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
name: mysql
spec:
replicas: 1
selector:
matchLabels:
app: mysql
template:
metadata:
labels:
app: mysql
spec:
containers:
- name: mysql
image: mysql:5.7
ports:
- containerPort: 3306
env:
- name: MYSQL_ROOT_PASSWORD
value: "123456"
volumeMounts:
- name: mysql-pvc
mountPath: /var/lib/mysql
- name: mysql-log
mountPath: /var/log/mysql
volumes:
- name: mysql-pvc
persistentVolumeClaim:
claimName: mysql-pvc
- name: mysql-log
hostPath:
path: /var/log/mysql
nodeSelector:
disktype: SSD
EOF
kubectl create -f mysql-dp.yaml
kubectl get pod -o wide
5.测试方法
1.创建nfs-pv
2.创建mysql-pvc
3.创建mysql-deployment并挂载mysq-pvc
4.登陆到mysql的pod里创建一个数据库
5.将这个pod删掉，因为deployment设置了副本数，所以会自动再创建一个新的pod
6.登录这个新的pod，查看刚才创建的数据库是否依然能看到
7.如果仍然能看到，则说明数据是持久化保存的
6.accessModes字段说明
ReadWriteOnce 单路读写
ReadOnlyMany 多路只读
ReadWriteMany 多路读写
resources 资源的限制，比如至少5G
7.volumeName精确匹配
#capacity 限制存储空间大小
#reclaim policy pv的回收策略
#retain pv被解绑后上面的数据仍保留
#recycle pv上的数据被释放
#delete pvc和pv解绑后pv就被删除
备注：用户在创建pod所需要的存储空间时，前提是必须要有pv存在
才可以，这样就不符合自动满足用户的需求，而且之前在k8s 9.0
版本还可删除pv，这样造成数据不安全性
configMap资源
1.为什么要用configMap？
将配置文件和POD解耦
2.congiMap里的配置文件是如何存储的？
键值对
key:value
文件名:配置文件的内容
3.configMap支持的配置类型
直接定义的键值对
基于文件创建的键值对
4.configMap创建方式
命令行
资源配置清单
5.configMap的配置文件如何传递到POD里
变量传递
数据卷挂载
6.命令行创建configMap
kubectl create configmap --help
kubectl create configmap nginx-config --from-literal=nginx_port=80 --from-literal=server_name=nginx.cookzhang.com
kubectl get cm
kubectl describe cm nginx-config
7.POD环境变量形式引用configMap
kubectl explain pod.spec.containers.env.valueFrom.configMapKeyRef
cat >nginx-cm.yaml <<EOF
apiVersion: v1
kind: Pod
metadata:
name: nginx-cm
spec:
containers:
- name: nginx-pod
image: nginx:1.14.0
ports:
- name: http
containerPort: 80
env:
- name: NGINX_PORT
valueFrom:
configMapKeyRef:
name: nginx-config
key: nginx_port
- name: SERVER_NAME
valueFrom:
configMapKeyRef:
name: nginx-config
key: server_name
EOF
kubectl create -f nginx-cm.yaml
8.查看pod是否引入了变量
[root@node1 ~/confimap]# kubectl exec -it nginx-cm /bin/bash
root@nginx-cm:~# echo ${NGINX_PORT}
80
root@nginx-cm:~# echo ${SERVER_NAME}
nginx.cookzhang.com
root@nginx-cm:~# printenv |egrep "NGINX_PORT|SERVER_NAME"
NGINX_PORT=80
SERVER_NAME=nginx.cookzhang.com
注意：
变量传递的形式，修改confMap的配置，POD内并不会生效
因为变量只有在创建POD的时候才会引用生效，POD一旦创建好，环境变量就不变了
8.文件形式创建configMap
创建配置文件：
cat >www.conf <<EOF
server {
listen 80;
server_name www.cookzy.com;
location / {
root /usr/share/nginx/html/www;
index index.html index.htm;
}
}
EOF
创建configMap资源：
kubectl create configmap nginx-www --from-file=www.conf=./www.conf
查看cm资源
kubectl get cm
kubectl describe cm nginx-www
编写pod并以存储卷挂载模式引用configMap的配置
cat >nginx-cm-volume.yaml <<EOF
apiVersion: v1
kind: Pod
metadata:
name: nginx-cm
spec:
containers:
- name: nginx-pod
image: nginx:1.14.0
ports:
- name: http
containerPort: 80
volumeMounts:
- name: nginx-www
mountPath: /etc/nginx/conf.d/
volumes:
- name: nginx-www
configMap:
name: nginx-www
items:
- key: www.conf
path: www.conf
EOF
测试：
1.进到容器内查看文件
kubectl exec -it nginx-cm /bin/bash
cat /etc/nginx/conf.d/www.conf
2.动态修改configMap
kubectl edit cm nginx-www
3.再次进入容器内观察配置会不会自动更新
cat /etc/nginx/conf.d/www.conf
nginx -T
安全认证和RBAC
API Server是访问控制的唯一入口
在k8s平台上的操作对象都要经历三种安全相关的操作
1.认证操作
http协议 token 认证令牌
ssl认证 kubectl需要证书双向认证
2.授权检查
RBAC 基于角色的访问控制
3.准入控制
进一步补充授权机制，一般在创建，删除，代理操作时作补充
k8s的api账户分为2类
1.实实在在的用户 人类用户 userAccount
2.POD客户端 serviceAccount 默认每个POD都有认真信息
RBAC就要角色的访问控制
你这个账号可以拥有什么权限
以traefik举例：
1.创建了账号 ServiceAccount:traefik-ingress-controller
2.创建角色 ClusterRole: traefik-ingress-controller
Role POD相关的权限
ClusterRole namespace级别操作
3.将账户和权限角色进行绑定 traefik-ingress-controller
RoleBinding
ClusterRoleBinding
4.创建POD时引用ServiceAccount
serviceAccountName: traefik-ingress-controller
注意！！！
kubeadm安装的k8s集群，证书默认只有1年
k8s dashboard
1.官方项目地址
https://github.com/kubernetes/dashboard
2.下载配置文件
wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-rc5/aio/deploy/recommended.yaml
3.修改配置文件
39 spec:
40 type: NodePort
41 ports:
42 - port: 443
43 targetPort: 8443
44 nodePort: 30000
4.应用资源配置
kubectl create -f recommended.yaml
5.创建管理员账户并应用
cat > dashboard-admin.yaml<<EOF
apiVersion: v1
kind: ServiceAccount
metadata:
name: admin-user
namespace: kubernetes-dashboard
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
name: admin-user
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: cluster-admin
subjects:
- kind: ServiceAccount
name: admin-user
namespace: kubernetes-dashboard
EOF
kubectl create -f dashboard-admin.yaml
6.查看资源并获取token
kubectl get pod -n kubernetes-dashboard -o wide
kubectl get svc -n kubernetes-dashboard
kubectl get secret -n kubernetes-dashboard
kubectl -n kubernetes-dashboard describe secret $(kubectl -n kubernetes-dashboard get secret | grep admin-user | awk '{print $1}')
7.浏览器访问
https://10.0.0.11:30000
google浏览器打不开就换火狐浏览器
黑科技
this is unsafe
研究的方向
0.namespace
1.ServiceAccount
2.Service
3.Secret
4.configMap
5.RBAC
6.Deployment
重启k8s二进制安装(kubeadm)需要重启组件
1.kube-apiserver
2.kube-proxy
3.kube-sechduler
4.kube-controller
5.etcd
6.coredns
7.flannel
8.traefik
9.docker
10.kubelet
掌握—》熟悉—》了解
- 掌握：倒背如流。
- 熟悉：正背如流。
- 了解：看到能够想起。
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