Helm 介绍

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Helm 是一个 Kubernetes 应用的包管理工具

介绍

  • Charts: 是用来封装 Kubernetes 原生应用程序的 YAML 文件，可以定义应用程序的 metadata 等，便于应用程序分发
  • Repository: Charts 仓库，HTTP/s 服务
  • Release: Charts 在 Kubernetes 上的实例

helm 和 chart 的主要作用：

  • 应用程序打包
  • 版本管理
  • 依赖检查
  • 应用包分发

helm 软件市场

使用

helm create <chart-name>：创建新的 chart
helm dependency list <chart-name>：管理 chart 依赖
helm install <name> <chart-name>：安装 chart
helm lint <chart-name>：检查 chart 配置是否有误
helm list：列出所有 release
helm package <chart-name>：打包本地 chart
helm repo [list/...]：列出、增加、更新、删除 chart 仓库
helm rollback：回滚 release 到历史版本
helm pull：拉取远程 chart 到本地
helm search：使用关键词搜索 chart
helm uninstall：卸载 release
helm upgrade：升级 release
helm status <name>：查看已经安装 chart 的状态

创建 chart

helm create hugo-chart
  • chart 结构
# tree hugo-chart
hugo-chart
├── Chart.yaml                      # 该 Chart 版本信息
├── charts                          # 依赖chart（子chart）
├── templates                       # 该 chart 配置模板，用来渲染 kubernetes YAML
│   ├── NOTES.txt                   # 服务的连接信息
│   ├── _helpers.tpl                # 用于创建模板是的帮助类
│   ├── deployment.yaml             # kubernetes deployment 配置
│   ├── hpa.yaml                    # kubernetes autoscaling 配置
│   ├── ingress.yaml                # kubernetes ingress 配置
│   ├── service.yaml                # kubernetes service 配置
│   ├── serviceaccount.yaml         # kubernetes serviceaccount 配置
│   └── tests
│       └── test-connection.yaml    # helm 安装后测试
└── values.yaml                     # chart templates 中自定义配置的默认值

3 directories, 10 files

可以在templates目录加kubernetes其他对象的配置，比如ConfigMap、DaemonSet等 https://helm.sh/docs/chart_template_guide/getting_started/

安装

helm install [NAME] [CHART] [flags]

helm install --debug --dry-run hugo-chart ./hugo-chart
# 安装本地 chart
helm install -f mhugoalues.yaml hugo-chart ./hugo-chart
# 指定变量
helm install --set name=prod hugo-chart ./hugo-chart
# 指定变量的值为 string 类型
helm install --set-string long_int=1234567890 hugo-chart ./hugo-chart
# 指定引用的文件地址
helm install --set-file my_script=dothings.sh hugo-chart ./hugo-chart
# 同时指定多个变量
helm install --set foo=bar --set foo=newbar  hugo-chart ./hugo-chart
helm template hugo-chart-server hugo-chart --dry-run

helm dependency list

其中：

  • mhugoalues.yaml：自定义变量配置文件
  • hugo-chart：release 名称
  • ./hugo-chart：本地的 chart 目录

Helm chart 安装后会转化成 Kubernetes 中的资源对象，生成一个 chart release，可以使用 helm list 命令查看。

  • 取回
helm get manifest [name]

Demo

配置 repo 并搜索镜像

# helm version
version.BuildInfo{Version:"v3.4.1", GitCommit:"c4e74854886b2efe3321e185578e6db9be0a6e29", GitTreeState:"dirty", GoVersion:"go1.15.5"}

# helm repo add stable https://charts.helm.sh/stable
"stable" has been added to your repositories

# helm repo list
NAME  	URL
stable	https://charts.helm.sh/stable

# helm search repo stable
NAME                                 	CHART VERSION	APP VERSION            	DESCRIPTION
stable/acs-engine-autoscaler         	2.2.2        	2.1.1                  	DEPRECATED Scales worker nodes within agent pools

# helm search repo stable/mysql
8NAME            	CHART VERSION	APP VERSION	DESCRIPTION
stable/mysql    	1.6.9        	5.7.30     	DEPRECATED - Fast, reliable, scalable, and easy...
stable/mysqldump	2.6.2        	2.4.1      	DEPRECATED! - A Helm chart to help backup MySQL...

创建 nginx

# helm create nginx
Creating nginx
# helm package nginx
Successfully packaged chart and saved it to: /Users/xiexianbin/work/k8s/helm/nginx-0.1.0.tgz
# ll
total 8
drwxr-xr-x  7 xiexianbin  staff   224B Nov  1 11:39 nginx
-rw-r--r--  1 xiexianbin  staff   3.5K Nov  1 11:41 nginx-0.1.0.tgz
# helm install nginx-0.1.0.tgz --generate-name
NAME: nginx-0-1607398959
LAST DEPLOYED: Sun Nov  1 11:42:44 2020
NAMESPACE: default
STATUS: deployed
REVISION: 1
NOTES:
1. Get the application URL by running these commands:
  export POD_NAME=$(kubectl get pods --namespace default -l "app.kubernetes.io/name=nginx,app.kubernetes.io/instance=nginx-0-1607398959" -o jsonpath="{.items[0].metadata.name}")
  export CONTAINER_PORT=$(kubectl get pod --namespace default $POD_NAME -o jsonpath="{.spec.containers[0].ports[0].containerPort}")
  echo "Visit http://127.0.0.1:8080 to use your application"
  kubectl --namespace default port-forward $POD_NAME 8080:$CONTAINER_PORT
# export POD_NAME=$(kubectl get pods --namespace default -l "app.kubernetes.io/name=nginx,app.kubernetes.io/instance=nginx-0-1607398959" -o jsonpath="{.items[0].metadata.name}")
# export CONTAINER_PORT=$(kubectl get pod --namespace default $POD_NAME -o jsonpath="{.spec.containers[0].ports[0].containerPort}")
# echo "Visit http://127.0.0.1:8080 to use your application"
Visit http://127.0.0.1:8080 to use your application
# kubectl --namespace default port-forward $POD_NAME 8080:$CONTAINER_PORT
Forwarding from 127.0.0.1:8080 -> 80
Forwarding from [::1]:8080 -> 80
Handling connection for 8080
# helm list
NAME              	NAMESPACE	REVISION	UPDATED                             	STATUS  	CHART      	APP VERSION
nginx-0-1607398959	default  	1       	2020-12-08 11:42:44.176491 +0800 CST	deployed	nginx-0.1.0	1.16.0
➜  helm git:(master) ✗ helm package nginx
Successfully packaged chart and saved it to: /Users/xiexianbin/work/code/keybase/work.xiexianbin.cn/k8s/helm/nginx-0.1.1.tgz
➜  helm git:(master) ✗ helm upgrade nginx-0-1607398959 nginx-0.1.1.tgz
Release "nginx-0-1607398959" has been upgraded. Happy Helming!
NAME: nginx-0-1607398959
LAST DEPLOYED: Sun Nov  1 11:50:52 2020
NAMESPACE: default
STATUS: deployed
REVISION: 2
NOTES:
1. Get the application URL by running these commands:
  export POD_NAME=$(kubectl get pods --namespace default -l "app.kubernetes.io/name=nginx,app.kubernetes.io/instance=nginx-0-1607398959" -o jsonpath="{.items[0].metadata.name}")
  export CONTAINER_PORT=$(kubectl get pod --namespace default $POD_NAME -o jsonpath="{.spec.containers[0].ports[0].containerPort}")
  echo "Visit http://127.0.0.1:8080 to use your application"
  kubectl --namespace default port-forward $POD_NAME 8080:$CONTAINER_PORT
➜  helm git:(master) ✗ helm history nginx-0-1607398959
REVISION	UPDATED                 	STATUS    	CHART      	APP VERSION	DESCRIPTION
1       	Sun Nov  1 11:42:44 2020	superseded	nginx-0.1.0	1.16.0     	Install complete
2       	Sun Nov  1 11:50:52 2020	deployed  	nginx-0.1.1	1.16.0     	Upgrade complete
➜  helm git:(master) ✗➜  helm git:(master) ✗ helm package nginx
Successfully packaged chart and saved it to: /Users/xiexianbin/work/code/keybase/work.xiexianbin.cn/k8s/helm/nginx-0.1.1.tgz
➜  helm git:(master) ✗ helm upgrade nginx-0-1607398959 nginx-0.1.1.tgz
Release "nginx-0-1607398959" has been upgraded. Happy Helming!
NAME: nginx-0-1607398959
LAST DEPLOYED: Sun Nov  1 11:50:52 2020
NAMESPACE: default
STATUS: deployed
REVISION: 2
NOTES:
1. Get the application URL by running these commands:
  export POD_NAME=$(kubectl get pods --namespace default -l "app.kubernetes.io/name=nginx,app.kubernetes.io/instance=nginx-0-1607398959" -o jsonpath="{.items[0].metadata.name}")
  export CONTAINER_PORT=$(kubectl get pod --namespace default $POD_NAME -o jsonpath="{.spec.containers[0].ports[0].containerPort}")
  echo "Visit http://127.0.0.1:8080 to use your application"
  kubectl --namespace default port-forward $POD_NAME 8080:$CONTAINER_PORT
➜  helm git:(master) ✗ helm history nginx-0-1607398959
REVISION	UPDATED                 	STATUS    	CHART      	APP VERSION	DESCRIPTION
1       	Sun Nov  1 11:42:44 2020	superseded	nginx-0.1.0	1.16.0     	Install complete
2       	Sun Nov  1 11:50:52 2020	deployed  	nginx-0.1.1	1.16.0     	Upgrade complete
➜  helm git:(master) ✗ helm rollback nginx-0-1607398959 1
Rollback was a success! Happy Helming!
➜  helm git:(master) ✗ helm history nginx-0-1607398959
REVISION	UPDATED                 	STATUS    	CHART      	APP VERSION	DESCRIPTION
1       	Sun Nov  1 11:42:44 2020	superseded	nginx-0.1.0	1.16.0     	Install complete
2       	Sun Nov  1 11:50:52 2020	superseded	nginx-0.1.1	1.16.0     	Upgrade complete
3       	Sun Nov  1 11:51:43 2020	deployed  	nginx-0.1.0	1.16.0     	Rollback to 1
➜  helm git:(master) ✗ helm status nginx-0-1607398959
NAME: nginx-0-1607398959
LAST DEPLOYED: Sun Nov  1 11:51:43 2020
NAMESPACE: default
STATUS: deployed
REVISION: 3
NOTES:
1. Get the application URL by running these commands:
  export POD_NAME=$(kubectl get pods --namespace default -l "app.kubernetes.io/name=nginx,app.kubernetes.io/instance=nginx-0-1607398959" -o jsonpath="{.items[0].metadata.name}")
  export CONTAINER_PORT=$(kubectl get pod --namespace default $POD_NAME -o jsonpath="{.spec.containers[0].ports[0].containerPort}")
  echo "Visit http://127.0.0.1:8080 to use your application"
  kubectl --namespace default port-forward $POD_NAME 8080:$CONTAINER_PORT
➜  helm git:(master) ✗ helm uninstall nginx-0-1607398959
release "nginx-0-1607398959" uninstalled
➜  helm git:(master) ✗ export HELM_EXPERIMENTAL_OCI=1
➜  helm git:(master) ✗ helm chart list
REF	NAME	VERSION	DIGEST	SIZE	CREATED
➜  helm git:(master) ✗
➜  helm git:(master) ✗ export HELM_EXPERIMENTAL_OCI=1
➜  helm git:(master) ✗ helm chart list
REF	NAME	VERSION	DIGEST	SIZE	CREATED
➜  helm git:(master) ✗ helm search repo wordpress
NAME            	CHART VERSION	APP VERSION	DESCRIPTION
stable/wordpress	9.0.3        	5.3.2      	DEPRECATED Web publishing platform for building...
➜  helm git:(master) ✗ helm install stable/wordpress -g
WARNING: This chart is deprecated
NAME: wordpress-1607399648
LAST DEPLOYED: Sun Nov  1 11:54:14 2020
NAMESPACE: default
STATUS: deployed
REVISION: 1
NOTES:
This Helm chart is deprecated

Given the `stable` deprecation timeline (https://github.com/helm/charts#deprecation-timeline), the Bitnami maintained Helm chart is now located at bitnami/charts (https://github.com/bitnami/charts/).

The Bitnami repository is already included in the Hubs and we will continue providing the same cadence of updates, support, etc that we've been keeping here these years. Installation instructions are very similar, just adding the _bitnami_ repo and using it during the installation (`bitnami/<chart>` instead of `stable/<chart>`)

$ helm repo add bitnami https://charts.bitnami.com/bitnami
$ helm install my-release bitnami/<chart>           # Helm 3
$ helm install --name my-release bitnami/<chart>    # Helm 2

To update an exisiting _stable_ deployment with a chart hosted in the bitnami repository you can execute

$ helm repo add bitnami https://charts.bitnami.com/bitnami
$ helm upgrade my-release bitnami/<chart>
helm pull  bitnami/wordpress --version 10.1.1

Issues and PRs related to the chart itself will be redirected to `bitnami/charts` GitHub repository. In the same way, we'll be happy to answer questions related to this migration process in this issue (https://github.com/helm/charts/issues/20969) created as a common place for discussion.

** Please be patient while the chart is being deployed **

To access your WordPress site from outside the cluster follow the steps below:

1. Get the WordPress URL by running these commands:

  NOTE: It may take a few minutes for the LoadBalancer IP to be available.
        Watch the status with: 'kubectl get svc --namespace default -w wordpress-1607399648'

   export SERVICE_IP=$(kubectl get svc --namespace default wordpress-1607399648 --template "{{ range (index .status.loadBalancer.ingress 0) }}{{.}}{{ end }}")
   echo "WordPress URL: http://$SERVICE_IP/"
   echo "WordPress Admin URL: http://$SERVICE_IP/admin"

2. Open a browser and access WordPress using the obtained URL.

3. Login with the following credentials below to see your blog:

  echo Username: user
  echo Password: $(kubectl get secret --namespace default wordpress-1607399648 -o jsonpath="{.data.wordpress-password}" | base64 --decode)
➜  helm git:(master) ✗

chart 私有 repo 搭建

参考：https://github.com/jdolitsky/helm-servecm

安装

$ mkdir -p /data/helm/local-repo
$ helm plugin install https://github.com/jdolitsky/helm-servecm
Installed plugin: servecm
If ChartMuseum is not installed, it will ask to install the latest stable release upon use:

$ helm servecm
ChartMuseum not installed. Install latest stable release? (type "yes"): yes
Attempting to install ChartMuseum server (v0.12.0)...
Detected your os as "linux"
+ curl -LO https://s3.amazonaws.com/chartmuseum/release/v0.12.0/bin/linux/amd64/chartmuseum
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 52.5M  100 52.5M    0     0   947k      0  0:00:56  0:00:56 --:--:-- 1234k
+ chmod +x ./chartmuseum
+ mv ./chartmuseum /usr/local/bin
+ set +x
2020-11-01 11:00:23.191316 I | Missing required flags(s): --storage
Error: plugin "servecm" exited with error

启动本地repo仓库服务

nohup helm servecm --debug --port=8879 \
  --storage="local" \
  --storage-local-rootdir="/data/helm/local-repo" &
  • 通过helm repo add命令添加本地repo：
# helm repo add local-repo http://172.20.0.50:8879
"local-repo" has been added to your repositories
  • 查看本地chart仓库是否添加成功
# helm repo list
NAME      	URL
local-repo	http://172.20.0.50:8879

备注：

  • helm serve 不指定任何参数的话会在默认的repo目录（/root/.helm/repository/local）启动服务，根据该目录下的软件包（tgz）信息在该目录下创建index.html文件。
  • 可以通过指定--repo-path参数实现在自定义的目录下启动服务，并在那个目录下创建index.html文件。

向repo中增加软件包

上面步骤中，已经创建了一个本地的repo，接下来讲述如何在repo中增加一个可用来部署的软件包chart。chart须遵循 SemVer 2 规则填写正确的版本格式。各种chart包可以在github下载。

  • 将chart文件夹移动到repo目录，并将chart打包：
cd /data/helm/local-repo
helm create hugo-chart
helm package hugo-chart
helm repo index .

备注:

  • helm package的作用是在当前目录下将软件打包为tgz，假如这个软件包中有requirement.yaml，则打包时还需要加上–dependency-update，用来update dependencies from “requirements.yaml” to dir “charts/” before packaging – –save=false的作用是不将tgz文件再拷贝一份到默认的local chart repo文件夹（/root/.helm/repository/local/）下，否则默认会将tgz拷贝一份到那，并检查那个目录下的index.html是否存在，不存在会报错。或者在3.2中最后把没用到的local repo删掉，就不用加–save=false了。

  • 更新index.yaml文件

通过helm repo index 命令将chart的metadata记录更新在index.yaml文件中:

cd /data/helm/local-repo
helm repo index --url=http://ip:8879 .
helm repo update

helm repo add local http://127.0.0.1:8879/charts helm install local/drupal

验证

查找新上传的chart:

# helm search repo hugo
NAME              	CHART VERSION	APP VERSION	DESCRIPTION
local-repo/hugo-chart	0.1.0        	1.16.0     	A Helm chart for Kubernetes

安装chart软件包（即release过程）：

# helm install hugo-chart local-repo/hugo-chart --dry-run
NAME: hugo-chart
LAST DEPLOYED: Thu Dec 17 11:08:33 2020
NAMESPACE: default
STATUS: pending-install
REVISION: 1
HOOKS:
---
# Source: hugo-chart/templates/tests/test-connection.yaml
apiVersion: v1
kind: Pod
metadata:
  name: "hugo-chart-test-connection"
  labels:
    helm.sh/chart: hugo-chart-0.1.0
    app.kubernetes.io/name: hugo-chart
    app.kubernetes.io/instance: hugo-chart
    app.kubernetes.io/version: "1.16.0"
    app.kubernetes.io/managed-by: Helm
  annotations:
    "helm.sh/hook": test
spec:
  containers:
    - name: wget
      image: busybox
      command: ['wget']
      args: ['hugo-chart:80']
  restartPolicy: Never
MANIFEST:
---
# Source: hugo-chart/templates/serviceaccount.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  name: hugo-chart
  labels:
    helm.sh/chart: hugo-chart-0.1.0
    app.kubernetes.io/name: hugo-chart
    app.kubernetes.io/instance: hugo-chart
    app.kubernetes.io/version: "1.16.0"
    app.kubernetes.io/managed-by: Helm
---
# Source: hugo-chart/templates/service.yaml
apiVersion: v1
kind: Service
metadata:
  name: hugo-chart
  labels:
    helm.sh/chart: hugo-chart-0.1.0
    app.kubernetes.io/name: hugo-chart
    app.kubernetes.io/instance: hugo-chart
    app.kubernetes.io/version: "1.16.0"
    app.kubernetes.io/managed-by: Helm
spec:
  type: ClusterIP
  ports:
    - port: 80
      targetPort: http
      protocol: TCP
      name: http
  selector:
    app.kubernetes.io/name: hugo-chart
    app.kubernetes.io/instance: hugo-chart
---
# Source: hugo-chart/templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: hugo-chart
  labels:
    helm.sh/chart: hugo-chart-0.1.0
    app.kubernetes.io/name: hugo-chart
    app.kubernetes.io/instance: hugo-chart
    app.kubernetes.io/version: "1.16.0"
    app.kubernetes.io/managed-by: Helm
spec:
  replicas: 1
  selector:
    matchLabels:
      app.kubernetes.io/name: hugo-chart
      app.kubernetes.io/instance: hugo-chart
  template:
    metadata:
      labels:
        app.kubernetes.io/name: hugo-chart
        app.kubernetes.io/instance: hugo-chart
    spec:
      serviceAccountName: hugo-chart
      securityContext:
        {}
      containers:
        - name: hugo-chart
          securityContext:
            {}
          image: "nginx:1.16.0"
          imagePullPolicy: IfNotPresent
          ports:
            - name: http
              containerPort: 80
              protocol: TCP
          livenessProbe:
            httpGet:
              path: /
              port: http
          readinessProbe:
            httpGet:
              path: /
              port: http
          resources:
            {}

NOTES:
1. Get the application URL by running these commands:
  export POD_NAME=$(kubectl get pods --namespace default -l "app.kubernetes.io/name=hugo-chart,app.kubernetes.io/instance=hugo-chart" -o jsonpath="{.items[0].metadata.name}")
  export CONTAINER_PORT=$(kubectl get pod --namespace default $POD_NAME -o jsonpath="{.spec.containers[0].ports[0].containerPort}")
  echo "Visit http://127.0.0.1:8080 to use your application"
  kubectl --namespace default port-forward $POD_NAME 8080:$CONTAINER_PORT

备注：helm install会用到socat，需要在所有节点上安装socat

helm hook

pre-install	Executes after templates are rendered, but before any resources are created in Kubernetes
post-install	Executes after all resources are loaded into Kubernetes
pre-delete	Executes on a deletion request before any resources are deleted from Kubernetes
post-delete	Executes on a deletion request after all of the release's resources have been deleted
pre-upgrade	Executes on an upgrade request after templates are rendered, but before any resources are updated
post-upgrade	Executes on an upgrade request after all resources have been upgraded
pre-rollback	Executes on a rollback request after templates are rendered, but before any resources are rolled back
post-rollback	Executes on a rollback request after all resources have been modified
test	Executes when the Helm test subcommand is invoked ( view test docs)

参考

  1. https://docs.helm.sh
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