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Pod是kubernetes的最小管理单元,在kubernetes中,按照pod的创建方式可以将其分为两类:
Pod控制器是管理pod的中间层,使用Pod控制器之后,只需要告诉Pod控制器,想要多少个什么样的Pod就可以了,它会创建出满足条件的Pod并确保每一个Pod资源处于用户期望的目标状态。如果Pod资源在运行中出现故障,它会基于指定策略重新编排Pod。
在kubernetes中,有很多类型的pod控制器,每种都有自己的适合的场景,常见的有下面这些:
ReplicationController:比较原始的pod控制器,已经被废弃,由ReplicaSet替代
ReplicaSet:保证副本数量一直维持在期望值,并支持pod数量扩缩容,镜像版本升级
Deployment:通过控制ReplicaSet来控制Pod,并支持滚动升级、回退版本
Horizontal Pod Autoscaler:可以根据集群负载自动水平伸缩调整Pod的数量,实现削峰填谷
DaemonSet:在集群中的指定Node上运行且仅运行一个副本,一般用于守护进程类的任务
Job:它创建出来的pod只要完成任务就立即退出,不需要重启或重建,用于执行一次性任务
Cronjob:它创建的Pod负责周期性任务控制,不需要持续后台运行
StatefulSet:管理有状态应用
ReplicaSet的主要作用是保证一定数量
的pod正常运行,它会持续监听
这些Pod的运行状态,一旦Pod发生故障,就会重启或重建。同时它还支持对pod数量的扩缩容和镜像版本的升降级
。
ReplicaSet的资源清单:
apiVersion: apps/v1 # 版本号 kind: ReplicaSet # 类型 metadata: # 元数据 name: # rs名称 namespace: # 所属命名空间 labels: #标签 controller: rs spec: # 详情描述 replicas: 3 # 副本数量 selector: # 选择器,通过它指定该控制器管理哪些pod matchLabels: # Labels匹配规则 app: nginx-pod matchExpressions: # Expressions匹配规则 - {key: app, operator: In, values: [nginx-pod]} template: # 模板,当副本数量不足时,会根据下面的模板创建pod副本 metadata: labels: app: nginx-pod spec: containers: - name: nginx image: nginx:1.17.1 ports: - containerPort: 80
看看spec里的几个属性:
replicas:指定副本数量,其实就是当前rs创建出来的pod的数量,默认为1
selector:选择器,它的作用是建立pod控制器和pod之间的关联关系,采用的Label Selector机制
template:模板,就是当前控制器创建pod所使用的模板板,里面其实就是前一章学过的pod的定义
创建pc-replicaset.yaml文件:
apiVersion: apps/v1 kind: ReplicaSet metadata: name: pc-replicaset namespace: dev spec: replicas: 3 selector: matchLabels: app: nginx-pod template: metadata: labels: app: nginx-pod spec: containers: - name: nginx image: nginx:1.17.1
创建RS:
[root@k8s-master01 ~] kubectl create -f pc-replicaset.yaml
replicaset.apps/pc-replicaset created
# 查看rs
# DESIRED:期望副本数量
# CURRENT:当前副本数量
# READY:已经准备好提供服务的副本数量
[root@k8s-master01 ~] kubectl get rs pc-replicaset -n dev -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES SELECTOR
pc-replicaset 3 3 3 22s nginx nginx:1.17.1 app=nginx-pod
查看一下创建出来的三个pod:
# 查看当前控制器创建出来的pod
# 这里发现控制器创建出来的pod的名称是在控制器名称后面拼接了-xxxxx随机码
[root@k8s-master01 ~] kubectl get pod -n dev
NAME READY STATUS RESTARTS AGE
pc-replicaset-6vmvt 1/1 Running 0 54s
pc-replicaset-fmb8f 1/1 Running 0 54s
pc-replicaset-snrk2 1/1 Running 0 54s
方式一:edit 编辑配置
# 编辑rs的副本数量,修改spec:replicas: 6即可
[root@k8s-master01 ~] kubectl edit rs pc-replicaset -n dev
replicaset.apps/pc-replicaset edited
# 查看pod
[root@k8s-master01 ~] kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-replicaset-6vmvt 1/1 Running 0 114m
pc-replicaset-cftnp 1/1 Running 0 10s
pc-replicaset-fjlm6 1/1 Running 0 10s
pc-replicaset-fmb8f 1/1 Running 0 114m
pc-replicaset-s2whj 1/1 Running 0 10s
pc-replicaset-snrk2 1/1 Running 0 114m
方式二:
scale指令
# 使用scale命令实现扩缩容, 后面--replicas=n直接指定目标数量即可
[root@k8s-master01 ~] kubectl scale rs pc-replicaset --replicas=2 -n dev
replicaset.apps/pc-replicaset scaled
# 命令运行完毕,立即查看,发现已经有4个开始准备退出了
[root@k8s-master01 ~] kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-replicaset-6vmvt 0/1 Terminating 0 118m
pc-replicaset-cftnp 0/1 Terminating 0 4m17s
pc-replicaset-fjlm6 0/1 Terminating 0 4m17s
pc-replicaset-fmb8f 1/1 Running 0 118m
pc-replicaset-s2whj 0/1 Terminating 0 4m17s
pc-replicaset-snrk2 1/1 Running 0 118m
#稍等片刻,就只剩下2个了
[root@k8s-master01 ~] kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-replicaset-fmb8f 1/1 Running 0 119m
pc-replicaset-snrk2 1/1 Running 0 119m
方式一:edit
# 编辑rs的容器镜像 - image: nginx:1.17.2
[root@k8s-master01 ~] kubectl edit rs pc-replicaset -n dev
replicaset.apps/pc-replicaset edited
# 再次查看,发现镜像版本已经变更了
[root@k8s-master01 ~] kubectl get rs -n dev -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES ...
pc-replicaset 2 2 2 140m nginx nginx:1.17.2 ...
方式二:
set image
kubectl set image rs rs名称 容器=镜像版本 -n namespace
[root@k8s-master01 ~] kubectl set image rs pc-replicaset nginx=nginx:1.17.1 -n dev
replicaset.apps/pc-replicaset image updated
# 再次查看,发现镜像版本已经变更了
[root@k8s-master01 ~] kubectl get rs -n dev -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES ...
pc-replicaset 2 2 2 145m nginx nginx:1.17.1 ...
使用kubectl delete命令会删除此RS以及它管理的Pod
# 在kubernetes删除RS前,会将RS的replicasclear调整为0,等待所有的Pod被删除后,在执行RS对象的删除
[root@k8s-master01 ~] kubectl delete rs pc-replicaset -n dev
replicaset.apps "pc-replicaset" deleted
[root@k8s-master01 ~] kubectl get pod -n dev -o wide
No resources found in dev namespace.
仅删除控制器RS,不删除下辖的pod,添加–cascade=false选项,即关闭级联(不推荐)
[root@k8s-master01 ~] kubectl delete rs pc-replicaset -n dev --cascade=false
replicaset.apps "pc-replicaset" deleted
[root@k8s-master01 ~] kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-replicaset-cl82j 1/1 Running 0 75s
pc-replicaset-dslhb 1/1 Running 0 75s
使用yaml删除
[root@k8s-master01 ~] kubectl delete -f pc-replicaset.yaml
replicaset.apps "pc-replicaset" deleted
在V1.2版本开始,引入了Deployment控制器,它并不直接管理pod,而是Deployment管理ReplicaSet,ReplicaSet管理Pod。
Deployment功能比RS更强大:
Deployment的资源清单文件:
apiVersion: apps/v1 # 版本号 kind: Deployment # 类型 metadata: # 元数据 name: # rs名称 namespace: # 所属命名空间 labels: #标签 controller: deploy spec: # 详情描述 replicas: 3 # 副本数量 revisionHistoryLimit: 3 # 保留历史版本的数量,方便以后回退。默认是10 paused: false # 暂停部署,默认是false。即创建出deploy后立即开始搞pod progressDeadlineSeconds: 600 # 部署超时时间(s),默认是600 strategy: # 策略 type: RollingUpdate # 滚动更新策略 rollingUpdate: # 滚动更新 maxSurge: 30% # 最大额外可以存在的副本数,可以为百分比,也可以为整数 maxUnavailable: 30% # 最大不可用状态的 Pod 的最大值,可以为百分比,也可以为整数 selector: # 选择器,通过它指定该控制器管理哪些pod matchLabels: # Labels匹配规则 app: nginx-pod matchExpressions: # Expressions匹配规则 - {key: app, operator: In, values: [nginx-pod]} template: # 模板,当副本数量不足时,会根据下面的模板创建pod副本 metadata: labels: app: nginx-pod spec: containers: - name: nginx image: nginx:1.17.1 ports: - containerPort: 80
pc-deployment.yaml,内容:
apiVersion: apps/v1 kind: Deployment metadata: name: pc-deployment namespace: dev spec: replicas: 3 selector: matchLabels: app: nginx-pod template: metadata: labels: app: nginx-pod spec: containers: - name: nginx image: nginx:1.17.1
创建:
kubectl create -f pc-deployment.yaml
通过scale指令:
# 变更副本数量为5个 [root@k8s-master01 ~] kubectl scale deploy pc-deployment --replicas=5 -n dev deployment.apps/pc-deployment scaled # 查看deployment [root@k8s-master01 ~] kubectl get deploy pc-deployment -n dev NAME READY UP-TO-DATE AVAILABLE AGE pc-deployment 5/5 5 5 2m # 查看pod [root@k8s-master01 ~] kubectl get pods -n dev NAME READY STATUS RESTARTS AGE pc-deployment-6696798b78-d2c8n 1/1 Running 0 4m19s pc-deployment-6696798b78-jxmdq 1/1 Running 0 94s pc-deployment-6696798b78-mktqv 1/1 Running 0 93s pc-deployment-6696798b78-smpvp 1/1 Running 0 4m19s pc-deployment-6696798b78-wvjd8 1/1 Running 0 4m19s
通过edit
# 编辑deployment的副本数量,修改spec:replicas: 4即可
[root@k8s-master01 ~] kubectl edit deploy pc-deployment -n dev
deployment.apps/pc-deployment edited
# 查看pod
[root@k8s-master01 ~] kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-deployment-6696798b78-d2c8n 1/1 Running 0 5m23s
pc-deployment-6696798b78-jxmdq 1/1 Running 0 2m38s
pc-deployment-6696798b78-smpvp 1/1 Running 0 5m23s
pc-deployment-6696798b78-wvjd8 1/1 Running 0 5m23s
deploy支持两种更新策略:
strategy:指定新的Pod替换旧的Pod的策略, 支持两个属性:
type:指定策略类型,支持两种策略
Recreate:在创建出新的Pod之前会先杀掉所有已存在的Pod
RollingUpdate:滚动更新,就是杀死一部分,就启动一部分,在更新过程中,存在两个版本Pod
-----
rollingUpdate:当type为RollingUpdate时生效,用于为RollingUpdate设置参数,支持两个属性:
maxUnavailable:用来指定在升级过程中不可用Pod的最大数量,默认为25%。即滚动过程中,有8个,则先干掉2个
maxSurge: 用来指定在升级过程中可以超过期望的Pod的最大数量,默认为25%。
重建更新:
编辑pc-deployment.yaml:
spec:
strategy: # 策略
type: Recreate # 重建更新
更新镜像
# 变更镜像
[root@k8s-master01 ~] kubectl set image deployment pc-deployment nginx=nginx:1.17.2 -n dev
deployment.apps/pc-deployment image updated
-w 观察镜像升级过程中pod的状态:
[root@k8s-master01 ~] kubectl get pods -n dev -w NAME READY STATUS RESTARTS AGE pc-deployment-5d89bdfbf9-65qcw 1/1 Running 0 31s pc-deployment-5d89bdfbf9-w5nzv 1/1 Running 0 31s pc-deployment-5d89bdfbf9-xpt7w 1/1 Running 0 31s pc-deployment-5d89bdfbf9-xpt7w 1/1 Terminating 0 41s pc-deployment-5d89bdfbf9-65qcw 1/1 Terminating 0 41s pc-deployment-5d89bdfbf9-w5nzv 1/1 Terminating 0 41s pc-deployment-675d469f8b-grn8z 0/1 Pending 0 0s pc-deployment-675d469f8b-hbl4v 0/1 Pending 0 0s pc-deployment-675d469f8b-67nz2 0/1 Pending 0 0s pc-deployment-675d469f8b-grn8z 0/1 ContainerCreating 0 0s pc-deployment-675d469f8b-hbl4v 0/1 ContainerCreating 0 0s pc-deployment-675d469f8b-67nz2 0/1 ContainerCreating 0 0s pc-deployment-675d469f8b-grn8z 1/1 Running 0 1s pc-deployment-675d469f8b-67nz2 1/1 Running 0 1s pc-deployment-675d469f8b-hbl4v 1/1 Running 0 2s
可以看到所有pod被同时删掉并重建。
滚动更新:
编辑pc-deployment.yaml:
spec:
strategy: # 策略
type: RollingUpdate # 滚动更新策略
rollingUpdate:
maxSurge: 25%
maxUnavailable: 25%
升级镜像:
[root@k8s-master01 ~] kubectl set image deployment pc-deployment nginx=nginx:1.17.3 -n dev
deployment.apps/pc-deployment image updated
-w观察升级过程:
[root@k8s-master01 ~] kubectl get pods -n dev -w NAME READY STATUS RESTARTS AGE pc-deployment-c848d767-8rbzt 1/1 Running 0 31m pc-deployment-c848d767-h4p68 1/1 Running 0 31m pc-deployment-c848d767-hlmz4 1/1 Running 0 31m pc-deployment-c848d767-rrqcn 1/1 Running 0 31m pc-deployment-966bf7f44-226rx 0/1 Pending 0 0s pc-deployment-966bf7f44-226rx 0/1 ContainerCreating 0 0s pc-deployment-966bf7f44-226rx 1/1 Running 0 1s pc-deployment-c848d767-h4p68 0/1 Terminating 0 34m pc-deployment-966bf7f44-cnd44 0/1 Pending 0 0s pc-deployment-966bf7f44-cnd44 0/1 ContainerCreating 0 0s pc-deployment-966bf7f44-cnd44 1/1 Running 0 2s pc-deployment-c848d767-hlmz4 0/1 Terminating 0 34m pc-deployment-966bf7f44-px48p 0/1 Pending 0 0s pc-deployment-966bf7f44-px48p 0/1 ContainerCreating 0 0s pc-deployment-966bf7f44-px48p 1/1 Running 0 0s pc-deployment-c848d767-8rbzt 0/1 Terminating 0 34m pc-deployment-966bf7f44-dkmqp 0/1 Pending 0 0s pc-deployment-966bf7f44-dkmqp 0/1 ContainerCreating 0 0s pc-deployment-966bf7f44-dkmqp 1/1 Running 0 2s pc-deployment-c848d767-rrqcn 0/1 Terminating 0 34m # 至此,新版本的pod创建完毕,就版本的pod销毁完毕
可以看到中间过程是滚动进行的,也就是边销毁边创建。过程图示:
上面更新镜像从1.17.1到1.17.2再到1.17.3时,查看RS的变化:
[root@k8s-master01 ~] kubectl get rs -n dev
NAME DESIRED CURRENT READY AGE
pc-deployment-6696798b78 0 0 0 7m37s
pc-deployment-6696798b11 0 0 0 5m37s
pc-deployment-c848d76789 4 4 4 72s
可以看到,旧版本RS下pod数量已经为0了,但RS并没有被删掉,这也是deploy支持版本回退的关键所在!!
deployment支持版本升级过程中的暂停、继续以及版本回退 ⇒ kubectl rollout
- status 显示当前升级状态
- history 显示 升级历史记录
- pause 暂停版本升级过程
- resume 继续已经暂停的版本升级过程
- restart 重启版本升级过程
undo
回滚到上一级版本(可以使用--to-revision
回滚到指定版本)
查看当前升级版本的状态:
[root@k8s-master01 ~] kubectl rollout status deploy pc-deployment -n dev
deployment "pc-deployment" successfully rolled out
查看升级历史记录:
[root@k8s-master01 ~] kubectl rollout history deploy pc-deployment -n dev
deployment.apps/pc-deployment
REVISION CHANGE-CAUSE
1 kubectl create --filename=pc-deployment.yaml --record=true
2 kubectl create --filename=pc-deployment.yaml --record=true
3 kubectl create --filename=pc-deployment.yaml --record=true
# 可以发现有三次版本记录,说明完成过两次升级
版本回滚:
# 这里直接使用--to-revision=1回滚到了1版本, 如果省略这个选项,就是回退到上个版本,就是2版本
[root@k8s-master01 ~] kubectl rollout undo deployment pc-deployment --to-revision=1 -n dev
deployment.apps/pc-deployment rolled back
# 查看发现,通过nginx镜像版本可以发现到了第一版
[root@k8s-master01 ~] kubectl get deploy -n dev -o wide
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES
pc-deployment 4/4 4 4 74m nginx nginx:1.17.1
查看rs,可以看到第一版本的RS下有pod,其余RS下pod数量为0:
# 其实deployment之所以可是实现版本的回滚,就是通过记录下历史rs来实现的,
# 一旦想回滚到哪个版本,只需要将当前版本pod数量降为0,然后将回滚版本的pod提升为目标数量就可以了
[root@k8s-master01 ~] kubectl get rs -n dev
NAME DESIRED CURRENT READY AGE
pc-deployment-6696798b78 4 4 4 78m
pc-deployment-966bf7f44 0 0 0 37m
pc-deployment-c848d767 0 0 0 71m
在这里就是更新一部分pod为新版本,并小部分的用户请求路由到新版本的Pod应用,如果运行没问题,再将剩余的pod也升级更新。
更新deployment的版本,并配置暂停deployment
[root@k8s-master01 ~] kubectl set image deploy pc-deployment nginx=nginx:1.17.4 -n dev && kubectl rollout pause deployment pc-deployment -n dev
deployment.apps/pc-deployment image updated
deployment.apps/pc-deployment paused
观察更新状态:
[root@k8s-master01 ~] kubectl rollout status deploy pc-deployment -n dev
Waiting for deployment "pc-deployment" rollout to finish: 2 out of 4 new replicas have been updated...
监控更新的过程,可以看到已经新增了一个资源,但是并未按照预期的状态去删除一个旧的资源,就是因为使用了pause暂停命令
[root@k8s-master01 ~] kubectl get rs -n dev -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES
pc-deployment-5d89bdfbf9 3 3 3 19m nginx nginx:1.17.1
pc-deployment-675d469f8b 0 0 0 14m nginx nginx:1.17.2
pc-deployment-6c9f56fcfb 2 2 2 3m16s nginx nginx:1.17.4
[root@k8s-master01 ~] kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-deployment-5d89bdfbf9-rj8sq 1/1 Running 0 7m33s
pc-deployment-5d89bdfbf9-ttwgg 1/1 Running 0 7m35s
pc-deployment-5d89bdfbf9-v4wvc 1/1 Running 0 7m34s
pc-deployment-6c9f56fcfb-996rt 1/1 Running 0 3m31s
pc-deployment-6c9f56fcfb-j2gtj 1/1 Running 0 3m31s
流量转给新pod一点,发现没有问题,继续更新
[root@k8s-master01 ~] kubectl rollout resume deploy pc-deployment -n dev
deployment.apps/pc-deployment resumed
查看更新后的情况:
[root@k8s-master01 ~] kubectl get rs -n dev -o wide
NAME DESIRED CURRENT READY AGE CONTAINERS IMAGES
pc-deployment-5d89bdfbf9 0 0 0 21m nginx nginx:1.17.1
pc-deployment-675d469f8b 0 0 0 16m nginx nginx:1.17.2
pc-deployment-6c9f56fcfb 4 4 4 5m11s nginx nginx:1.17.4
[root@k8s-master01 ~] kubectl get pods -n dev
NAME READY STATUS RESTARTS AGE
pc-deployment-6c9f56fcfb-7bfwh 1/1 Running 0 37s
pc-deployment-6c9f56fcfb-996rt 1/1 Running 0 5m27s
pc-deployment-6c9f56fcfb-j2gtj 1/1 Running 0 5m27s
pc-deployment-6c9f56fcfb-rf84v 1/1 Running 0 37s
最后,删除deploy:
# 其下的rs和pod也将被删除
[root@k8s-master01 ~] kubectl delete -f pc-deployment.yaml
deployment.apps "pc-deployment" deleted
kubectl delete deployment pc-deployment -n dev
前面相对pod进行扩缩容,可以kubectl scale或者kubectl edit改副本数,但都得人为手动干预去改。想实现自动化—活儿多的时候多起几个pod,活儿少的时候少起几个pod的自动化动态扩缩容,得用HPA
HPA可以获取每个Pod利用率,然后和HPA中定义的指标进行对比,同时计算出需要伸缩的具体值,最后实现Pod的数量的调整。
metrics-server可以用来收集集群中的资源使用情况。
# 安装git
[root@k8s-master01 ~] yum install git -y
# 获取metrics-server, 注意使用的版本
[root@k8s-master01 ~] git clone -b v0.3.6 https://github.com/kubernetes-incubator/metrics-server
# 修改deployment, 注意修改的是镜像和初始化参数
[root@k8s-master01 ~] cd /root/metrics-server/deploy/1.8+/
[root@k8s-master01 1.8+] vim metrics-server-deployment.yaml
按图中添加下面选项
hostNetwork: true
image: registry.cn-hangzhou.aliyuncs.com/google_containers/metrics-server-amd64:v0.3.6
args:
- --kubelet-insecure-tls
- --kubelet-preferred-address-types=InternalIP,Hostname,InternalDNS,ExternalDNS,ExternalIP
改完配置文件后,开始安装:
# 安装metrics-server
[root@k8s-master01 1.8+] kubectl apply -f ./
# metrics-server在kube-system空间以pod的形式运行
[root@k8s-master01 1.8+] kubectl get pod -n kube-system|grep -i metrics
metrics-server-6b976979db-2xwbj 1/1 Running 0 90s
kubectl top
查看集群中node、pod等占用的资源大小:
[root@k8s-master01 1.8+] kubectl top node
NAME CPU(cores) CPU% MEMORY(bytes) MEMORY%
k8s-master01 289m 14% 1582Mi 54%
k8s-node01 81m 4% 1195Mi 40%
k8s-node02 72m 3% 1211Mi 41%
[root@k8s-master01 1.8+] kubectl top pod -n kube-system
NAME CPU(cores) MEMORY(bytes)
coredns-6955765f44-7ptsb 3m 9Mi
coredns-6955765f44-vcwr5 3m 8Mi
etcd-master 14m 145Mi
...
创建pc-hpa-deployment.yaml文件,创建deployment:
apiVersion: apps/v1 kind: Deployment metadata: name: nginx namespace: dev spec: strategy: # 策略 type: RollingUpdate # 滚动更新策略 replicas: 1 selector: matchLabels: app: nginx-pod template: metadata: labels: app: nginx-pod spec: containers: - name: nginx image: nginx:1.17.1 resources: # 资源配额 limits: # 限制资源(上限) cpu: "1" # CPU限制,单位是core数 requests: # 请求资源(下限) cpu: "100m" # CPU限制,单位是core数
创建deploy和service:
# 创建deployment
[root@k8s-master01 1.8+] kubectl apply -f pc-hpa-deployment.yaml
# 创建service
[root@k8s-master01 1.8+] kubectl expose deployment nginx --type=NodePort --port=80 -n dev
# type=NodePort 集群外IP也可以访问
查看:
[root@k8s-master01 1.8+]# kubectl get deployment,pod,svc -n dev
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/nginx 1/1 1 1 47s
NAME READY STATUS RESTARTS AGE
pod/nginx-7df9756ccc-bh8dr 1/1 Running 0 47s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/nginx NodePort 10.101.18.29 <none> 80:31830/TCP 35s
创建pc-hpa.yaml文件,内容如下:
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
name: pc-hpa
namespace: dev
spec:
minReplicas: 1 #最小pod数量
maxReplicas: 10 #最大pod数量
targetCPUUtilizationPercentage: 3 # CPU使用率指标,3%方便一会儿实验
scaleTargetRef: # 指定要控制的nginx信息
apiVersion: /v1
kind: Deployment
name: nginx # 要调整的是名字叫nginx的deploy下的pod
创建HPA:
[root@k8s-master01 1.8+] kubectl create -f pc-hpa.yaml
horizontalpodautoscaler.autoscaling/pc-hpa created
# 查看hpa,unknown是正在算
[root@k8s-master01 1.8+] kubectl get hpa -n dev
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
pc-hpa Deployment/nginx <unknown>/3% 1 10 1 62s
# 算出来了,没有任何的请求访问,0%
[root@k8s-master01 1.8+] kubectl get hpa -n dev
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
pc-hpa Deployment/nginx 0%/3% 1 10 1 62s
使用压测工具对service地址host:31830进行压测,然后通过控制台查看hpa和pod的变化。这里不用Jmeter,PostMan就能达到要求,我在hpa中设置的限值为3%,很容易达到:
hpa的变化:
[root@k8s-master01 ~] kubectl get hpa -n dev -w
NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE
pc-hpa Deployment/nginx 0%/3% 1 10 1 4m11s
pc-hpa Deployment/nginx 0%/3% 1 10 1 5m19s
pc-hpa Deployment/nginx 22%/3% 1 10 1 6m50s
pc-hpa Deployment/nginx 22%/3% 1 10 4 7m5s
pc-hpa Deployment/nginx 22%/3% 1 10 8 7m21s
pc-hpa Deployment/nginx 6%/3% 1 10 8 7m51s
pc-hpa Deployment/nginx 0%/3% 1 10 8 9m6s
pc-hpa Deployment/nginx 0%/3% 1 10 8 13m
pc-hpa Deployment/nginx 0%/3% 1 10 1 14m
deployment变化
[root@k8s-master01 ~] kubectl get deployment -n dev -w NAME READY UP-TO-DATE AVAILABLE AGE nginx 1/1 1 1 11m nginx 1/4 1 1 13m nginx 1/4 1 1 13m nginx 1/4 1 1 13m nginx 1/4 4 1 13m nginx 1/8 4 1 14m nginx 1/8 4 1 14m nginx 1/8 4 1 14m nginx 1/8 8 1 14m nginx 2/8 8 2 14m nginx 3/8 8 3 14m nginx 4/8 8 4 14m nginx 5/8 8 5 14m nginx 6/8 8 6 14m nginx 7/8 8 7 14m nginx 8/8 8 8 15m nginx 8/1 8 8 20m nginx 8/1 8 8 20m nginx 1/1 1 1 20m
pod变化:
[root@k8s-master01 ~] kubectl get pods -n dev -w NAME READY STATUS RESTARTS AGE nginx-7df9756ccc-bh8dr 1/1 Running 0 11m nginx-7df9756ccc-cpgrv 0/1 Pending 0 0s nginx-7df9756ccc-8zhwk 0/1 Pending 0 0s nginx-7df9756ccc-rr9bn 0/1 Pending 0 0s nginx-7df9756ccc-cpgrv 0/1 ContainerCreating 0 0s nginx-7df9756ccc-8zhwk 0/1 ContainerCreating 0 0s nginx-7df9756ccc-rr9bn 0/1 ContainerCreating 0 0s nginx-7df9756ccc-m9gsj 0/1 Pending 0 0s nginx-7df9756ccc-g56qb 0/1 Pending 0 0s nginx-7df9756ccc-sl9c6 0/1 Pending 0 0s nginx-7df9756ccc-fgst7 0/1 Pending 0 0s nginx-7df9756ccc-g56qb 0/1 ContainerCreating 0 0s nginx-7df9756ccc-m9gsj 0/1 ContainerCreating 0 0s nginx-7df9756ccc-sl9c6 0/1 ContainerCreating 0 0s nginx-7df9756ccc-fgst7 0/1 ContainerCreating 0 0s nginx-7df9756ccc-8zhwk 1/1 Running 0 19s nginx-7df9756ccc-rr9bn 1/1 Running 0 30s nginx-7df9756ccc-m9gsj 1/1 Running 0 21s nginx-7df9756ccc-cpgrv 1/1 Running 0 47s nginx-7df9756ccc-sl9c6 1/1 Running 0 33s nginx-7df9756ccc-g56qb 1/1 Running 0 48s nginx-7df9756ccc-fgst7 1/1 Running 0 66s nginx-7df9756ccc-fgst7 1/1 Terminating 0 6m50s nginx-7df9756ccc-8zhwk 1/1 Terminating 0 7m5s nginx-7df9756ccc-cpgrv 1/1 Terminating 0 7m5s nginx-7df9756ccc-g56qb 1/1 Terminating 0 6m50s nginx-7df9756ccc-rr9bn 1/1 Terminating 0 7m5s nginx-7df9756ccc-m9gsj 1/1 Terminating 0 6m50s nginx-7df9756ccc-sl9c6 1/1 Terminating 0 6m50s
想实现集群中的每一台(或指定)节点上都运行某个pod副本,就得用DS控制器。
一般适用于日志收集、节点监控等场景。也就是说,如果一个
Pod提供的功能是节点级别
的(每个节点都需要且只需要一个)。
且:
DaemonSet的资源清单文件:
apiVersion: apps/v1 # 版本号 kind: DaemonSet # 类型 metadata: # 元数据 name: # rs名称 namespace: # 所属命名空间 labels: #标签 controller: daemonset spec: # 详情描述 revisionHistoryLimit: 3 # 保留历史版本 updateStrategy: # 更新策略 type: RollingUpdate # 滚动更新策略 rollingUpdate: # 滚动更新 maxUnavailable: 1 # 最大不可用状态的 Pod 的最大值,可以为百分比,也可以为整数 selector: # 选择器,通过它指定该控制器管理哪些pod matchLabels: # Labels匹配规则 app: nginx-pod matchExpressions: # Expressions匹配规则 - {key: app, operator: In, values: [nginx-pod]} template: # 模板,当副本数量不足时,会根据下面的模板创建pod副本 metadata: labels: app: nginx-pod spec: containers: - name: nginx image: nginx:1.17.1 ports: - containerPort: 80
创建pc-daemonset.yaml:
apiVersion: apps/v1 kind: DaemonSet metadata: name: pc-daemonset namespace: dev spec: selector: matchLabels: app: nginx-pod template: metadata: labels: app: nginx-pod spec: containers: - name: nginx image: nginx:1.17.1
创建DS:
[root@k8s-master01 ~] kubectl create -f pc-daemonset.yaml
daemonset.apps/pc-daemonset created
查看DS和pod:发现在每个Node上都运行一个pod
[root@k8s-master01 ~] kubectl get ds -n dev -o wide
NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES
pc-daemonset 2 2 2 2 2 24s nginx nginx:1.17.1
# 查看pod,发现在每个Node上都运行一个pod
[root@k8s-master01 ~] kubectl get pods -n dev -o wide
NAME READY STATUS RESTARTS AGE IP NODE
pc-daemonset-9bck8 1/1 Running 0 37s 10.244.1.43 node1
pc-daemonset-k224w 1/1 Running 0 37s 10.244.2.74 node2
删除DS:
[root@k8s-master01 ~] kubectl delete -f pc-daemonset.yaml
daemonset.apps "pc-daemonset" deleted
kubectl delete ds pc-daemonset pc-daemonset -ndev
Job,主要用于负责
批量
处理(一次要处理指定数量任务)短暂的一次性
(每个任务仅运行一次就结束) 任务。
特点:
Job的资源清单文件:
apiVersion: batch/v1 # 版本号 kind: Job # 类型 metadata: # 元数据 name: # rs名称 namespace: # 所属命名空间 labels: #标签 controller: job spec: # 详情描述 completions: 1 # 指定job需要成功运行Pods的总次数。即一共要运行多少个一次性任务。默认值: 1 parallelism: 1 # 指定job在任一时刻并发运行Pods的数量。默认值: 1 activeDeadlineSeconds: 30 # 指定job可运行的时间期限,超过时间还未结束,系统将会尝试进行终止。 backoffLimit: 6 # 指定job失败后进行重试的次数。默认是6 manualSelector: true # 是否可以使用selector选择器选择pod,默认是false selector: # 选择器,通过它指定该控制器管理哪些pod matchLabels: # Labels匹配规则 app: counter-pod matchExpressions: # Expressions匹配规则 - {key: app, operator: In, values: [counter-pod]} template: # 模板,当副本数量不足时,会根据下面的模板创建pod副本 metadata: labels: app: counter-pod spec: restartPolicy: Never # 重启策略只能设置为Never或者OnFailure containers: - name: counter image: busybox:1.30 command: ["bin/sh","-c","for i in 9 8 7 6 5 4 3 2 1; do echo $i;sleep 2;done"]
如completions: 6 且 parallelism: 2,即有六个任务,每次并发执行两个,三轮就成功运行了。注意Job中重启策略只能设置为Never或者OnFailure
关于重启策略设置的说明:
如果指定为OnFailure,则job会在pod出现故障时重启容器,而不是创建pod,failed次数不变
如果指定为Never,则job会在pod出现故障时创建新的pod,并且故障pod不会消失,也不会重启,failed次数加1
如果指定为Always的话,就意味着一直重启,意味着job任务会重复去执行了,当然不对,所以不能设置为Always
job中的pod本来就是一次性的,任务跑完pod走人,设置成always,执行完任务的pod又会被再次重启,导致任务一直重复执行。
创建pc-job.yaml:
apiVersion: batch/v1 kind: Job metadata: name: pc-job namespace: dev spec: manualSelector: true selector: matchLabels: app: counter-pod template: metadata: labels: app: counter-pod spec: restartPolicy: Never containers: - name: counter image: busybox:1.30 command: ["bin/sh","-c","for i in 9 8 7 6 5 4 3 2 1; do echo $i;sleep 3;done"] # 倒计时功能
在容器中写个倒计时的小任务,创建job:
[root@k8s-master01 ~] kubectl create -f pc-job.yaml
job.batch/pc-job created
-w观察一下job状态的变化:
[root@k8s-master01 ~] kubectl get job -n dev -o wide -w
NAME COMPLETIONS DURATION AGE CONTAINERS IMAGES SELECTOR
pc-job 0/1 21s 21s counter busybox:1.30 app=counter-pod
pc-job 1/1 31s 79s counter busybox:1.30 app=counter-pod
# 即29秒后,成功一个任务/一个任务
通过观察pod状态可以看到,pod在运行完毕任务后,就会变成Completed状态
[root@k8s-master01 ~] kubectl get pods -n dev -w
NAME READY STATUS RESTARTS AGE
pc-job-rxg96 1/1 Running 0 29s
pc-job-rxg96 0/1 Completed 0 33s
修改pod的总数量和并发的数量:
# completions: 6 # 指定job需要成功运行Pods的次数为6 # parallelism: 3 # 指定job并发运行Pods的数量为3 # 然后重新运行job,观察效果,此时会发现,job会每次运行3个pod,总共执行了6个pod [root@k8s-master01 ~] kubectl get pods -n dev -w NAME READY STATUS RESTARTS AGE pc-job-684ft 1/1 Running 0 5s pc-job-jhj49 1/1 Running 0 5s pc-job-pfcvh 1/1 Running 0 5s pc-job-684ft 0/1 Completed 0 11s pc-job-v7rhr 0/1 Pending 0 0s pc-job-v7rhr 0/1 Pending 0 0s pc-job-v7rhr 0/1 ContainerCreating 0 0s pc-job-jhj49 0/1 Completed 0 11s pc-job-fhwf7 0/1 Pending 0 0s pc-job-fhwf7 0/1 Pending 0 0s pc-job-pfcvh 0/1 Completed 0 11s pc-job-5vg2j 0/1 Pending 0 0s pc-job-fhwf7 0/1 ContainerCreating 0 0s pc-job-5vg2j 0/1 Pending 0 0s pc-job-5vg2j 0/1 ContainerCreating 0 0s pc-job-fhwf7 1/1 Running 0 2s pc-job-v7rhr 1/1 Running 0 2s pc-job-5vg2j 1/1 Running 0 3s pc-job-fhwf7 0/1 Completed 0 12s pc-job-v7rhr 0/1 Completed 0 12s pc-job-5vg2j 0/1 Completed 0 12s
# 删除job
# 使用yaml文件删除资源,不用指定资源类型
[root@k8s-master01 ~] kubectl delete -f pc-job.yaml
job.batch "pc-job" deleted
立即执行
特定的时间点
去反复的运行
job任务。
CronJob的资源清单文件:
apiVersion: batch/v1beta1 # 版本号 kind: CronJob # 类型 metadata: # 元数据 name: # rs名称 namespace: # 所属命名空间 labels: #标签 controller: cronjob spec: # 详情描述 schedule: # cron格式的作业调度运行时间点,用于控制任务在什么时间执行 concurrencyPolicy: # 并发执行策略,用于定义前一次作业运行尚未完成时是否以及如何运行后一次的作业 failedJobHistoryLimit: # 为失败的任务执行保留的历史记录数,默认为1 successfulJobHistoryLimit: # 为成功的任务执行保留的历史记录数,默认为3 startingDeadlineSeconds: # 启动作业错误的超时时长 jobTemplate: # job控制器模板,用于为cronjob控制器生成job对象;下面其实就是job的定义 metadata: spec: completions: 1 parallelism: 1 activeDeadlineSeconds: 30 backoffLimit: 6 manualSelector: true selector: matchLabels: app: counter-pod matchExpressions: 规则 - {key: app, operator: In, values: [counter-pod]} template: metadata: labels: app: counter-pod spec: restartPolicy: Never containers: - name: counter image: busybox:1.30 command: ["bin/sh","-c","for i in 9 8 7 6 5 4 3 2 1; do echo $i;sleep 20;done"]
新参数解释:
schedule: cron表达式,用于指定任务的执行时间
*/1 * * * *
<分钟> <小时> <日> <月份> <星期>
分钟 值从 0 到 59.
小时 值从 0 到 23.
日 值从 1 到 31.
月 值从 1 到 12.
星期 值从 0 到 6, 0 代表星期日
多个时间可以用逗号隔开; 范围可以用连字符给出;*可以作为通配符; /表示每...
---------------------------------
concurrencyPolicy:
Allow: 允许Jobs并发运行(默认)
Forbid: 禁止并发运行,如果上一次运行尚未完成,则跳过下一次运行
Replace: 替换,取消当前正在运行的作业并用新作业替换它
创建pc-cronjob.yaml:
apiVersion: batch/v1beta1 kind: CronJob metadata: name: pc-cronjob namespace: dev labels: controller: cronjob spec: schedule: "*/1 * * * *" # 每分钟执行一次 jobTemplate: metadata: spec: template: spec: restartPolicy: Never containers: - name: counter image: busybox:1.30 command: ["bin/sh","-c","for i in 9 8 7 6 5 4 3 2 1; do echo $i;sleep 3;done"]
# 创建cronjob [root@k8s-master01 ~] kubectl create -f pc-cronjob.yaml cronjob.batch/pc-cronjob created # 查看cronjob [root@k8s-master01 ~] kubectl get cronjobs -n dev NAME SCHEDULE SUSPEND ACTIVE LAST SCHEDULE AGE pc-cronjob */1 * * * * False 0 <none> 6s # 查看job [root@k8s-master01 ~] kubectl get jobs -n dev NAME COMPLETIONS DURATION AGE pc-cronjob-1592587800 1/1 28s 3m26s pc-cronjob-1592587860 1/1 28s 2m26s # 一分钟后又开始新的job pc-cronjob-1592587920 1/1 28s 86s # 查看pod [root@k8s-master01 ~] kubectl get pods -n dev pc-cronjob-1592587800-x4tsm 0/1 Completed 0 2m24s pc-cronjob-1592587860-r5gv4 0/1 Completed 0 84s pc-cronjob-1592587920-9dxxq 1/1 Running 0 24s
# 删除cronjob
[root@k8s-master01 ~] kubectl delete -f pc-cronjob.yaml
cronjob.batch "pc-cronjob" deleted
到此,K8s常用的pod控制器结束。下一篇:Service
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