首发于kubernetes 实践手册
介绍如何快速上手使用 Helm。
1、前提条件
在使用 Helm 前,需具备以下前提条件:
2、Helm 版本选择
Helm 是基于 Kubernetes 之上实现的,在选择 Helm 版本时需要考虑对应的 Kubernetes 版本。
当一个 Helm 的新版本发布时,它会针对 Kubernetes 的一个特定的次版本进行编译。比如,Helm 3.0.0 与 Kubernetes 的 1.16.2 的客户端版本交互,一次可以兼容 Kubernetes 1.16。
对于最新 Helm 版本,建议使用当前 Kubernetes 的最新稳定版本。
如果您选择了一个 Kubernetes 版本不支持的 Helm 版本,在使用过程中将面临未知的风险。
建议参考下表,以满足与 Kubernetes 的兼容性:
更多参考 Helm 版本支持策略
2、安装
可以通过 homebrew (macOS 下包管理工具)下载二进制 Helm 安装包,也可以通过 Github 下载。
2.1 macOS
2.2 二进制安装
每个 Helm 版本都提供了各种操作系统对应的二进制版本包,这些版本可以手动下载和安装。
下载所需的版本。
解压(如:tar -zxvf helm-v3.7.1-linux-amd64.tar.gz
)。
在解压目录中找到 helm 程序,移动到需要的目录中(如:mv linux-amd64/helm /usr/local/bin/helm
)。
更多安装方式参考:安装 Helm
3、初始化
当已经安装好 Helm 之后,可以添加一个 chart 仓库。可从 Artifact Hub 中查找有效的 Helm chart 仓库。
TIP:通过 Artifact Hub 几乎可以找到任何想要的 chart 包,并能找到对应的源码(github 地址),然后就可以参考、修改为定制化的 chart 啦!
$ helm repo add bitnami https://charts.bitnami.com/bitnami
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当添加完成,您将可以看到可以被您安装的 charts 列表:
$ helm search repo bitnami
NAME CHART VERSION APP VERSION DESCRIPTION
bitnami/bitnami-common 0.0.9 0.0.9 DEPRECATED Chart with custom templates used in ...
bitnami/airflow 8.0.2 2.0.0 Apache Airflow is a platform to programmaticall...
bitnami/apache 8.2.3 2.4.46 Chart for Apache HTTP Server
bitnami/aspnet-core 1.2.3 3.1.9 ASP.NET Core is an open-source framework create...
# ... and many more
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4、安装 Chart 示例
通过 helm install
命令安装 chart。 Helm 可以通过多种途径查找和安装 chart,但最简单的是安装官方的 bitnami charts。
$ helm repo update # 确定我们可以拿到最新的 charts 列表
$ helm install bitnami/mysql --generate-name
NAME: mysql-1612624192
LAST DEPLOYED: Sat Feb 6 16:09:56 2021
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES: ...
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在上面的例子中,bitnami/mysql 这个 chart 被发布,名字是 mysql-1612624192
您可以通过执行 helm show chart bitnami/mysql
命令简单的了解到这个 chart 的基本信息。 或者您可以执行 helm show all bitnami/mysql
获取关于该 chart 的所有信息。
每当您执行 helm install 的时候,都会创建一个新的发布版本。 所以一个 chart 在同一个集群里面可以被安装多次,每一个都可以被独立的管理和升级。
5、卸载
可以使用 helm uninstall
命令卸载你的版本。
$ helm uninstall mysql-1612624192
release "mysql-1612624192" uninstalled
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该命令会从 Kubernetes 卸载 mysql-1612624192, 它将删除和该版本相关的所有相关资源(service、deployment、 pod 等)甚至版本历史。
如果您在执行 helm uninstall
的时候提供 --keep-history 选项, Helm 将会保存版本历史。 您可以通过命令查看该版本的信息
$ helm status mysql-1612624192
Status: UNINSTALLED
...
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因为 --keep-history 选项会让 helm 跟踪你的版本(即使你卸载了他们),所以你可以审计集群历史甚至使用 helm rollback 回滚版本。
6、Helm 命令
如果您想通过 Helm 命令查看更多的有用的信息,请使用 helm -h 命令,或者在任意命令后添加 -h 选项:
$ helm -h
The Kubernetes package manager
Common actions for Helm:
- helm search: search for charts
- helm pull: download a chart to your local directory to view
- helm install: upload the chart to Kubernetes
- helm list: list releases of charts
Environment variables:
| Name | Description |
|------------------------------------|-----------------------------------------------------------------------------------|
| $HELM_CACHE_HOME | set an alternative location for storing cached files. |
| $HELM_CONFIG_HOME | set an alternative location for storing Helm configuration. |
| $HELM_DATA_HOME | set an alternative location for storing Helm data. |
| $HELM_DEBUG | indicate whether or not Helm is running in Debug mode |
| $HELM_DRIVER | set the backend storage driver. Values are: configmap, secret, memory, sql. |
| $HELM_DRIVER_SQL_CONNECTION_STRING | set the connection string the SQL storage driver should use. |
| $HELM_MAX_HISTORY | set the maximum number of helm release history. |
| $HELM_NAMESPACE | set the namespace used for the helm operations. |
| $HELM_NO_PLUGINS | disable plugins. Set HELM_NO_PLUGINS=1 to disable plugins. |
| $HELM_PLUGINS | set the path to the plugins directory |
| $HELM_REGISTRY_CONFIG | set the path to the registry config file. |
| $HELM_REPOSITORY_CACHE | set the path to the repository cache directory |
| $HELM_REPOSITORY_CONFIG | set the path to the repositories file. |
| $KUBECONFIG | set an alternative Kubernetes configuration file (default "~/.kube/config") |
| $HELM_KUBEAPISERVER | set the Kubernetes API Server Endpoint for authentication |
| $HELM_KUBECAFILE | set the Kubernetes certificate authority file. |
| $HELM_KUBEASGROUPS | set the Groups to use for impersonation using a comma-separated list. |
| $HELM_KUBEASUSER | set the Username to impersonate for the operation. |
| $HELM_KUBECONTEXT | set the name of the kubeconfig context. |
| $HELM_KUBETOKEN | set the Bearer KubeToken used for authentication. |
Helm stores cache, configuration, and data based on the following configuration order:
- If a HELM_*_HOME environment variable is set, it will be used
- Otherwise, on systems supporting the XDG base directory specification, the XDG variables will be used
- When no other location is set a default location will be used based on the operating system
By default, the default directories depend on the Operating System. The defaults are listed below:
| Operating System | Cache Path | Configuration Path | Data Path |
|------------------|---------------------------|--------------------------------|-------------------------|
| Linux | $HOME/.cache/helm | $HOME/.config/helm | $HOME/.local/share/helm |
| macOS | $HOME/Library/Caches/helm | $HOME/Library/Preferences/helm | $HOME/Library/helm |
| Windows | %TEMP%\helm | %APPDATA%\helm | %APPDATA%\helm |
Usage:
helm [command]
Available Commands:
completion generate autocompletion scripts for the specified shell
create create a new chart with the given name
dependency manage a chart's dependencies
env helm client environment information
get download extended information of a named release
help Help about any command
history fetch release history
install install a chart
lint examine a chart for possible issues
list list releases
package package a chart directory into a chart archive
plugin install, list, or uninstall Helm plugins
pull download a chart from a repository and (optionally) unpack it in local directory
repo add, list, remove, update, and index chart repositories
rollback roll back a release to a previous revision
search search for a keyword in charts
show show information of a chart
status display the status of the named release
template locally render templates
test run tests for a release
uninstall uninstall a release
upgrade upgrade a release
verify verify that a chart at the given path has been signed and is valid
version print the client version information
Flags:
--debug enable verbose output
-h, --help help for helm
--kube-apiserver string the address and the port for the Kubernetes API server
--kube-as-group stringArray group to impersonate for the operation, this flag can be repeated to specify multiple groups.
--kube-as-user string username to impersonate for the operation
--kube-ca-file string the certificate authority file for the Kubernetes API server connection
--kube-context string name of the kubeconfig context to use
--kube-token string bearer token used for authentication
--kubeconfig string path to the kubeconfig file
-n, --namespace string namespace scope for this request
--registry-config string path to the registry config file (default "/Users/xcbeyond/Library/Preferences/helm/registry.json")
--repository-cache string path to the file containing cached repository indexes (default "/Users/xcbeyond/Library/Caches/helm/repository")
--repository-config string path to the file containing repository names and URLs (default "/Users/xcbeyond/Library/Preferences/helm/repositories.yaml")
Use "helm [command] --help" for more information about a command.
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