Kubernetes
10/25/26About 7 min
Namespace
名称空间用来隔离资源
kubectl create ns hello
kubectl delete ns helloapiVersion: v1
kind: Namespace
metadata:
name: helloPod
运行中的一组容器，Pod是kubernetes中应用的最小单位.
kubectl run mynginx --image=nginx# 查看default名称空间的Pod
kubectl get pod
# 描述
kubectl describe pod 你自己的Pod名字
# 删除
kubectl delete pod Pod名字
# 查看Pod的运行日志
kubectl logs Pod名字# 每个Pod - k8s都会分配一个ip
kubectl get pod -o wide
# 使用Pod的ip+pod里面运行容器的端口kubectl apply -f pod.yml
kubectl delete -f pod.yml
curl 192.168.169.136
# 集群中的任意一个机器以及任意的应用都能通过Pod分配的ip来访问这个PodapiVersion: v1
kind: Pod
metadata:
labels:
run: mynginx
name: mynginx
# namespace: default
spec:
containers:
- image: nginx
name: mynginxapiVersion: v1
kind: Pod
metadata:
labels:
run: myapp
name: myapp
spec:
containers:
- image: nginx
name: nginx
- image: tomcat:8.5.68
name: tomcatDeployment
控制Pod，使Pod拥有多副本，自愈，扩缩容等能力
# 清除所有Pod，比较下面两个命令有何不同效果？
kubectl run mynginx --image=nginxkubectl create deployment mytomcat --image=tomcat:8.5.68
# 自愈能力
kubectl get deploy多副本
kubectl create deployment my-dep --image=nginx --replicas=3
kubectl delete deploy my-depapiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: my-dep
name: my-dep
spec:
replicas: 3
selector:
matchLabels:
app: my-dep
template:
metadata:
labels:
app: my-dep
spec:
containers:
- image: nginx
name: nginx扩缩容
kubectl scale --replicas=5 deployment/my-dep
kubectl edit deployment my-dep
#修改 replicas自愈&故障转移
- 停机
- 删除Pod
- 容器崩溃
- ....
滚动更新
kubectl set image deployment/my-dep nginx=nginx:1.16.1 --record
kubectl rollout status deployment/my-dep# 修改
kubectl edit deployment/my-dep版本回退
#历史记录
kubectl rollout history deployment/my-dep#查看某个历史详情
kubectl rollout history deployment/my-dep --revision=2#回滚(回到上次)
kubectl rollout undo deployment/my-dep#回滚(回到指定版本)
kubectl rollout undo deployment/my-dep --to-revision=2更多：
除了Deployment，k8s还有StatefulSet、DaemonSet、Job等类型资源。我们都称为工作负载。
有状态应用使用 StatefulSet 部署，无状态应用使用 Deployment 部署
https://kubernetes.io/zh/docs/concepts/workloads/controllers/
Service
将一组 Pods 公开为网络服务的抽象方法。
#暴露Deploy, port为service端口,target port为pod端口
kubectl expose deployment my-dep --port=8000 --target-port=80
kubectl get service
curl <service ip>:8000
# 在pod中用服务名.名称空间.svc 的域名访问
curl my-dep.default.svc:8000
# 使用标签检索Pod
kubectl get pod -l app=my-depapiVersion: v1
kind: Service
metadata:
labels:
app: my-dep
name: my-dep
spec:
selector:
app: my-dep
ports:
- port: 8000
protocol: TCP
targetPort: 80ClusterIP
# 等同于没有--type的
kubectl expose deployment my-dep --port=8000 --target-port=80 --type=ClusterIPapiVersion: v1
kind: Service
metadata:
labels:
app: my-dep
name: my-dep
spec:
ports:
- port: 8000
protocol: TCP
targetPort: 80
selector:
app: my-dep
type: ClusterIPNodePort
kubectl expose deployment my-dep --port=8000 --target-port=80 --type=NodePort
kubectl get service
curl <集群内ip>:8000
# NodePort范围在 30000-32767 之间
curl <master节点公网ip>:30562apiVersion: v1
kind: Service
metadata:
labels:
app: my-dep
name: my-dep
spec:
ports:
- port: 8000
protocol: TCP
targetPort: 80
selector:
app: my-dep
type: NodePortIngress
安装
wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.47.0/deploy/static/provider/baremetal/deploy.yaml#修改镜像
vi deploy.yaml
#将image的值改为如下值：
registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/ingress-nginx-controller:v0.46.0# 检查安装的结果
kubectl get pod,svc -n ingress-nginx# 最后别忘记把svc暴露的端口要放行使用
测试环境
应用如下yaml，准备好测试环境
apiVersion: apps/v1
kind: Deployment
metadata:
name: hello-server
spec:
replicas: 2
selector:
matchLabels:
app: hello-server
template:
metadata:
labels:
app: hello-server
spec:
containers:
- name: hello-server
image: registry.cn-hangzhou.aliyuncs.com/lfy_k8s_images/hello-server
ports:
- containerPort: 9000
---
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: nginx-demo
name: nginx-demo
spec:
replicas: 2
selector:
matchLabels:
app: nginx-demo
template:
metadata:
labels:
app: nginx-demo
spec:
containers:
- image: nginx
name: nginx
---
apiVersion: v1
kind: Service
metadata:
labels:
app: nginx-demo
name: nginx-demo
spec:
selector:
app: nginx-demo
ports:
- port: 8000
protocol: TCP
targetPort: 80
---
apiVersion: v1
kind: Service
metadata:
labels:
app: hello-server
name: hello-server
spec:
selector:
app: hello-server
ports:
- port: 8000
protocol: TCP
targetPort: 9000域名访问
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: ingress-host-bar
spec:
ingressClassName: nginx
rules:
- host: "hello.atguigu.com"
http:
paths:
- pathType: Prefix
path: "/"
backend:
service:
name: hello-server
port:
number: 8000
- host: "demo.atguigu.com"
http:
paths:
- pathType: Prefix
path: "/nginx" # 把请求会转给下面的服务，下面的服务一定要能处理这个路径，不能处理就是404
backend:
service:
name: nginx-demo ## java，比如使用路径重写，去掉前缀nginx
port:
number: 8000路径重写
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$2
name: ingress-host-bar
spec:
ingressClassName: nginx
rules:
- host: "hello.atguigu.com"
http:
paths:
- pathType: Prefix
path: "/"
backend:
service:
name: hello-server
port:
number: 8000
- host: "demo.atguigu.com"
http:
paths:
- pathType: Prefix
path: "/nginx(/|$)(.*)" # 把请求会转给下面的服务，下面的服务一定要能处理这个路径，不能处理就是404
backend:
service:
name: nginx-demo ## java，比如使用路径重写，去掉前缀nginx
port:
number: 8000流量限制
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: ingress-limit-rate
annotations:
nginx.ingress.kubernetes.io/limit-rps: "1"
spec:
ingressClassName: nginx
rules:
- host: "haha.atguigu.com"
http:
paths:
- pathType: Exact
path: "/"
backend:
service:
name: nginx-demo
port:
number: 8000存储抽象
环境准备
所有节点
#所有机器安装
yum install -y nfs-utils主节点
#nfs主节点
echo "/nfs/data/ *(insecure,rw,sync,no_root_squash)" > /etc/exports
mkdir -p /nfs/data
systemctl enable rpcbind --now
systemctl enable nfs-server --now
#配置生效
exportfs -r从节点
# master节点ip
showmount -e 172.31.0.4
#执行以下命令挂载 nfs 服务器上的共享目录到本机路径 /root/nfsmount
mkdir -p /nfs/data
mount -t nfs 172.31.0.4:/nfs/data /nfs/data
# 写入一个测试文件
echo "hello nfs server" > /nfs/data/test.txt原生方式数据挂载
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: nginx-pv-demo
name: nginx-pv-demo
spec:
replicas: 2
selector:
matchLabels:
app: nginx-pv-demo
template:
metadata:
labels:
app: nginx-pv-demo
spec:
containers:
- image: nginx
name: nginx
volumeMounts:
- name: html
mountPath: /usr/share/nginx/html
volumes:
- name: html
nfs:
server: 172.31.0.4
path: /nfs/data/nginx-pvPV&PVC
PV：持久卷（Persistent Volume），将应用需要持久化的数据保存到指定位置
PVC：持久卷申明（Persistent Volume Claim），申明需要使用的持久卷规格
创建pv池
#nfs主节点
mkdir -p /nfs/data/01
mkdir -p /nfs/data/02
mkdir -p /nfs/data/03创建PV
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv01-10m
spec:
capacity:
storage: 10M
accessModes:
- ReadWriteMany
storageClassName: nfs
nfs:
path: /nfs/data/01
server: 172.31.0.4
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv02-1gi
spec:
capacity:
storage: 1Gi
accessModes:
- ReadWriteMany
storageClassName: nfs
nfs:
path: /nfs/data/02
server: 172.31.0.4
---
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv03-3gi
spec:
capacity:
storage: 3Gi
accessModes:
- ReadWriteMany
storageClassName: nfs
nfs:
path: /nfs/data/03
server: 172.31.0.4PVC创建与绑定
创建PVC
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: nginx-pvc
spec:
accessModes:
- ReadWriteMany
resources:
requests:
storage: 200Mi
storageClassName: nfs创建Pod绑定PVC
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: nginx-deploy-pvc
name: nginx-deploy-pvc
spec:
replicas: 2
selector:
matchLabels:
app: nginx-deploy-pvc
template:
metadata:
labels:
app: nginx-deploy-pvc
spec:
containers:
- image: nginx
name: nginx
volumeMounts:
- name: html
mountPath: /usr/share/nginx/html
volumes:
- name: html
persistentVolumeClaim:
claimName: nginx-pvcConfigMap
抽取应用配置，并且可以自动更新
把之前的配置文件创建为配置集
# 创建配置，redis保存到k8s的etcd；
kubectl create cm redis-conf --from-file=redis.confapiVersion: v1
data: #data是所有真正的数据，key：默认是文件名 value：配置文件的内容
redis.conf: |
appendonly yes
kind: ConfigMap
metadata:
name: redis-conf
namespace: default创建Pod
apiVersion: v1
kind: Pod
metadata:
name: redis
spec:
containers:
- name: redis
image: redis
command:
- redis-server
- "/redis-master/redis.conf" #指的是redis容器内部的位置
ports:
- containerPort: 6379
volumeMounts:
- mountPath: /data
name: data
- mountPath: /redis-master
name: config
volumes:
- name: data
emptyDir: {}
- name: config
configMap:
name: redis-conf
items:
- key: redis.conf
path: redis.conf检查默认配置
kubectl exec -it redis -- redis-cli
127.0.0.1:6379> CONFIG GET appendonly
127.0.0.1:6379> CONFIG GET requirepass修改ConfigMap
apiVersion: v1
kind: ConfigMap
metadata:
name: example-redis-config
data:
redis-config: |
maxmemory 2mb
maxmemory-policy allkeys-lru检查配置是否更新
kubectl exec -it redis -- redis-cli
127.0.0.1:6379> CONFIG GET maxmemory
127.0.0.1:6379> CONFIG GET maxmemory-policy检查指定文件内容是否已经更新
修改了CM。Pod里面的配置文件会跟着变
配置值未更改，因为需要重新启动 Pod 才能从关联的 ConfigMap 中获取更新的值。
原因：我们的Pod部署的中间件自己本身没有热更新能力
Secret
Secret 对象类型用来保存敏感信息，例如密码、OAuth 令牌和 SSH 密钥。 将这些信息放在 secret 中比放在 Pod 的定义或者 容器镜像 中来说更加安全和灵活。
kubectl create secret docker-registry leifengyang-docker \
--docker-username=leifengyang \
--docker-password=Lfy123456 \
[email protected]
##命令格式
kubectl create secret docker-registry regcred \
--docker-server=<你的镜像仓库服务器> \
--docker-username=<你的用户名> \
--docker-password=<你的密码> \
--docker-email=<你的邮箱地址>apiVersion: v1
kind: Pod
metadata:
name: private-nginx
spec:
containers:
- name: private-nginx
image: leifengyang/guignginx:v1.0
imagePullSecrets:
- name: leifengyang-dockerkubectl exec $POD_NAME -- env