28.Kubernetes的包管理利器：Helm使用进阶
Helm是一种管理Charts的工具，而charts则是打包预配置Kubernetes基础资源的配置合集。
上一章节我们学习了Helm的认知和部署安装，这一章节中我们将学习自定义chart制作、打包和发布，release的版本发布和回滚功能，希望能给大家学习Helm起到抛砖引玉的作用。
1.自定义chart制作
1）首先我们先创建我们myapp的chart项目
#进入local仓库的目录
[root@centos-1 local]# cd /root/.helm/repository/local
#创myapp项目
$ helm create mongodb
[root@centos-1 local]# tree
.
├── index.yaml
└── myapp
├── charts
├── Chart.yaml
├── templates
│ ├── deployment.yaml
│ ├── _helpers.tpl
│ ├── ingress.yaml
│ ├── NOTES.txt
│ └── service.yaml
└── values.yaml
2）接着，按需修改Chart.yaml、values.yaml
#Chart.yaml
apiVersion: v1
appVersion: "1.3" #pod版本
description: myapp web service
name: myapp
version: 0.1.0 #release版本
#values.yaml
# Default values for myapp.
# This is a YAML-formatted file.
# Declare variables to be passed into your templates.
replicaCount: 1
image:
repository: registry.cn-hangzhou.aliyuncs.com/aaron89/myapp
tag: v1
pullPolicy: IfNotPresent
service:
type: ClusterIP
port: 80
ingress:
enabled: false
annotations: {}
# kubernetes.io/ingress.class: nginx
# kubernetes.io/tls-acme: "true"
path: /
hosts:
- chart-example.local
tls: []
# - secretName: chart-example-tls
# hosts:
# - chart-example.local
resources:
# We usually recommend not to specify default resources and to leave this as a conscious
# choice for the user. This also increases chances charts run on environments with little
# resources, such as Minikube. If you do want to specify resources, uncomment the following
# lines, adjust them as necessary, and remove the curly braces after 'resources:'.
limits:
cpu: 100m
memory: 128Mi
requests:
cpu: 100m
memory: 128Mi
nodeSelector: {}
tolerations: []
affinity: {}
3）使用lint进行项目的语法检查
[root@centos-1 local]# helm lint myapp
==> Linting myapp
[INFO] Chart.yaml: icon is recommended
1 chart(s) linted, no failures
4）本地myapp项目发布，可以使用–dry-run进行检测,也可以使用set命令进行临时传参
[root@centos-1 local]# helm install -n myapp ./myapp/ --set service.type=NodePort --dry-run
NAME: myapp
[root@centos-1 local]# helm install -n myapp ./myapp/ --set service.type=NodePort
NAME: myapp
LAST DEPLOYED: Tue Dec 17 17:35:10 2019
NAMESPACE: default
STATUS: DEPLOYED
RESOURCES:
==> v1/Deployment
NAME READY UP-TO-DATE AVAILABLE AGE
myapp 0/1 1 0 <invalid>
==> v1/Pod(related)
NAME READY STATUS RESTARTS AGE
myapp-78cfb4645b-2q65q 0/1 ContainerCreating 0 <invalid>
==> v1/Service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
myapp NodePort 10.103.135.152 <none> 80:32441/TCP <invalid>
NOTES:
1. Get the application URL by running these commands:
export NODE_PORT=$(kubectl get --namespace default -o jsonpath="{.spec.ports[0].nodePort}" services myapp)
export NODE_IP=$(kubectl get nodes --namespace default -o jsonpath="{.items[0].status.addresses[0].address}")
echo http://$NODE_IP:$NODE_PORT
5）查看release发布情况，至此发布已经成功了
[root@centos-1 local]# helm list
NAME REVISION UPDATED STATUS CHART NAMESPACE
myapp 1 Tue Dec 17 17:35:10 2019 DEPLOYED myapp-0.1.0 default
2.release迭代
第一次发布好之后，我们要如何进行后续版本的更新呢？并且需要注意什么呢？
1.) 首先，修改Chart.yaml和values.yaml，你需要确保version: 0.1.1字段必须不同
#Chart.yaml
apiVersion: v1
appVersion: "1.4" #pod版本
description: myapp web service
name: myapp
version: 0.1.1 #release版本
#values.yaml
replicaCount: 1
image:
repository: registry.cn-hangzhou.aliyuncs.com/aaron89/myapp
tag: v4 #修改镜像tag
pullPolicy: IfNotPresent
2.）使用upgrade命令升级release
[root@centos-1 local]# helm upgrade myapp ./myapp --set service.type=NodePort
Release "myapp" has been upgraded. Happy Helming!
LAST DEPLOYED: Tue Dec 17 17:41:29 2021
NAMESPACE: default
STATUS: DEPLOYED
RESOURCES:
==> v1/Deployment
NAME READY UP-TO-DATE AVAILABLE AGE
myapp 1/1 0 1 6m15s
==> v1/Pod(related)
NAME READY STATUS RESTARTS AGE
myapp-5c8b9d645f-jjp6c 0/1 ContainerCreating 0 0s
myapp-78cfb4645b-2q65q 1/1 Running 0 6m15s
==> v1/Service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
myapp NodePort 10.103.135.152 <none> 80:32441/TCP 6m15s
NOTES:
1. Get the application URL by running these commands:
export NODE_PORT=$(kubectl get --namespace default -o jsonpath="{.spec.ports[0].nodePort}" services myapp)
export NODE_IP=$(kubectl get nodes --namespace default -o jsonpath="{.items[0].status.addresses[0].address}")
echo http://$NODE_IP:$NODE_PORT
3）发现CHART已经成功更新至myapp-0.1.1版本，同时REVISION=2
[root@centos-1 local]# helm list
NAME REVISION UPDATED STATUS CHART NAMESPACE
myapp 2 Tue Dec 17 17:41:29 2019 DEPLOYED myapp-0.1.1 default
此时，后续版本的迭代更新也演示完毕了。
3.release回滚
对于回滚的需求，helm也是支持的。
1）使用rollback命令进行回滚，回滚到版本1
注意：rollback命令需要两个位置参数：release name和revision number
[root@centos-1 local]# helm rollback myapp 1
Rollback was a success! Happy Helming!
2）回滚成功，CHART为myapp-0.1.0，此时REVISION=3（递增的版本号）
[root@centos-1 local]# helm list
NAME REVISION UPDATED STATUS CHART NAMESPACE
myapp 3 Tue Dec 17 17:46:12 2921 DEPLOYED myapp-0.1.0 default
3）我们再来查看项目情况
[root@centos-1 local]# helm status myapp
LAST DEPLOYED: Tue Dec 17 17:46:12 2021
NAMESPACE: default
STATUS: DEPLOYED
RESOURCES:
==> v1/Deployment
NAME READY UP-TO-DATE AVAILABLE AGE
myapp 1/1 1 1 14m
==> v1/Pod(related)
NAME READY STATUS RESTARTS AGE
myapp-78cfb4645b-zj9pv 1/1 Running 0 3m34s
==> v1/Service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
myapp NodePort 10.103.135.152 <none> 80:32441/TCP 14m
NOTES:
1. Get the application URL by running these commands:
export NODE_PORT=$(kubectl get --namespace default -o jsonpath="{.spec.ports[0].nodePort}" services myapp)
export NODE_IP=$(kubectl get nodes --namespace default -o jsonpath="{.items[0].status.addresses[0].address}")
echo http://$NODE_IP:$NODE_PORT
4.自定义chart打包并发布
对于已更新的版本，我们接下来要做的事情就是打包发布了。
1）使用package打包myapp项目
[root@centos-1 local]# helm package ./myapp/
Successfully packaged chart and saved it to: /root/.helm/repository/local/myapp-0.1.1.tgz
2）创建项目存放路径，并把打包好的项目丢过去
mkdir -p /data/repo
mv myapp /data/repo
3）使用serve启动local仓库
[root@centos-1 local]# helm serve --repo-path /data/repo --url /charts
Regenerating index. This may take a moment.
Now serving you on 127.0.0.1:8879
4）这时，我们就可以在local仓库找到我们打包的项目了
[root@centos-1 ~]# helm search local
NAME CHART VERSION APP VERSION DESCRIPTION
local/myapp 0.1.1 1.4 myapp web service
stable/magic-ip-address 0.1.0 0.9.0 A Helm chart to assign static IP addresses for ...
5.命令补全
最后，为了使用方便，可使用以下命令进行helm命令的自动补全功能设置:
source <(helm completion bash)