Helm
Helm 是一个类似于 yum/apt/homebrew 的 Kubernetes 应用管理工具。Helm 使用 Chart 来管理 Kubernetes manifest 文件。
Helm 基本使用
安装 helm
客户端
brew install kubernetes-helm
初始化 Helm 并安装 Tiller
服务(需要事先配置好 kubectl)
helm init
对于 Kubernetes v1.16.0 以上的版本,有可能会碰到 Error: error installing: the server could not find the requested resource
的错误。这是由于 extensions/v1beta1
已经被 apps/v1
替代,解决方法是
kubectl create serviceaccount --namespace kube-system tiller
kubectl create clusterrolebinding tiller --clusterrole=cluster-admin --serviceaccount=kube-system:tiller
helm init --service-account tiller --override spec.selector.matchLabels.'name'='tiller',spec.selector.matchLabels.'app'='helm' --output yaml | sed 's@apiVersion: extensions/v1beta1@apiVersion: apps/v1@' | kubectl apply -f -
更新 charts 列表
helm repo update
部署服务,比如 mysql
➜ ~ helm install stable/mysql
NAME: quieting-warthog
LAST DEPLOYED: Tue Feb 21 16:13:02 2017
NAMESPACE: default
STATUS: DEPLOYED
RESOURCES:
==> v1/Secret
NAME TYPE DATA AGE
quieting-warthog-mysql Opaque 2 1s
==> v1/PersistentVolumeClaim
NAME STATUS VOLUME CAPACITY ACCESSMODES AGE
quieting-warthog-mysql Pending 1s
==> v1/Service
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
quieting-warthog-mysql 10.3.253.105 <none> 3306/TCP 1s
==> extensions/v1beta1/Deployment
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
quieting-warthog-mysql 1 1 1 0 1s
NOTES:
MySQL can be accessed via port 3306 on the following DNS name from within your cluster:
quieting-warthog-mysql.default.svc.cluster.local
To get your root password run:
kubectl get secret --namespace default quieting-warthog-mysql -o jsonpath="{.data.mysql-root-password}" | base64 --decode; echo
To connect to your database:
1. Run an Ubuntu pod that you can use as a client:
kubectl run -i --tty ubuntu --image=ubuntu:16.04 --restart=Never -- bash -il
2. Install the mysql client:
$ apt-get update && apt-get install mysql-client -y
3. Connect using the mysql cli, then provide your password:
$ mysql -h quieting-warthog-mysql -p
更多命令的使用方法可以参考下面的 “Helm 命令参考” 部分。
Helm 工作原理
基本概念
Helm 的三个基本概念
- Chart:Helm 应用(package),包括该应用的所有 Kubernetes manifest 模版,类似于 YUM RPM 或 Apt dpkg 文件
- Repository:Helm package 存储仓库
- Release:chart 的部署实例,每个 chart 可以部署一个或多个 release
Helm 工作原理
Helm 包括两个部分,helm
客户端和 tiller
服务端。
the client is responsible for managing charts, and the server is responsible for managing releases.
helm 客户端
helm 客户端是一个命令行工具,负责管理 charts、repository 和 release。它通过 gPRC API(使用 kubectl port-forward
将 tiller 的端口映射到本地,然后再通过映射后的端口跟 tiller 通信)向 tiller 发送请求,并由 tiller 来管理对应的 Kubernetes 资源。
helm
命令的使用方法可以参考下面的 “Helm 命令参考” 部分。
tiller 服务端
tiller 接收来自 helm 客户端的请求,并把相关资源的操作发送到 Kubernetes,负责管理(安装、查询、升级或删除等)和跟踪 Kubernetes 资源。为了方便管理,tiller 把 release 的相关信息保存在 kubernetes 的 ConfigMap 中。
tiller 对外暴露 gRPC API,供 helm 客户端调用。
Helm Charts
Helm 使用 Chart 来管理 Kubernetes manifest 文件。每个 chart 都至少包括
- 应用的基本信息
Chart.yaml
- 一个或多个 Kubernetes manifest 文件模版(放置于 templates / 目录中),可以包括 Pod、Deployment、Service 等各种 Kubernetes 资源
Chart.yaml 示例
name: The name of the chart (required)
version: A SemVer 2 version (required)
description: A single-sentence description of this project (optional)
keywords:
- A list of keywords about this project (optional)
home: The URL of this project's home page (optional)
sources:
- A list of URLs to source code for this project (optional)
maintainers: # (optional)
- name: The maintainer's name (required for each maintainer)
email: The maintainer's email (optional for each maintainer)
engine: gotpl # The name of the template engine (optional, defaults to gotpl)
icon: A URL to an SVG or PNG image to be used as an icon (optional).
依赖管理
Helm 支持两种方式管理依赖的方式:
- 直接把依赖的 package 放在
charts/
目录中 - 使用
requirements.yaml
并用helm dep up foochart
来自动下载依赖的 packages
dependencies:
- name: apache
version: 1.2.3
repository: http://example.com/charts
- name: mysql
version: 3.2.1
repository: http://another.example.com/charts
Chart 模版
Chart 模板基于 Go template 和 Sprig,比如
apiVersion: v1
kind: ReplicationController
metadata:
name: deis-database
namespace: deis
labels:
heritage: deis
spec:
replicas: 1
selector:
app: deis-database
template:
metadata:
labels:
app: deis-database
spec:
serviceAccount: deis-database
containers:
- name: deis-database
image: {{.Values.imageRegistry}}/postgres:{{.Values.dockerTag}}
imagePullPolicy: {{.Values.pullPolicy}}
ports:
- containerPort: 5432
env:
- name: DATABASE_STORAGE
value: {{default "minio" .Values.storage}}
模版参数的默认值必须放到 values.yaml
文件中,其格式为
imageRegistry: "quay.io/deis"
dockerTag: "latest"
pullPolicy: "alwaysPull"
storage: "s3"
# 依赖的 mysql chart 的默认参数
mysql:
max_connections: 100
password: "secret"
Helm 插件
插件提供了扩展 Helm 核心功能的方法,它在客户端执行,并放在 $(helm home)/plugins
目录中。
一个典型的 helm 插件格式为
$(helm home)/plugins/
|- keybase/
|
|- plugin.yaml
|- keybase.sh
而 plugin.yaml 格式为
name: "keybase"
version: "0.1.0"
usage: "Integreate Keybase.io tools with Helm"
description: |-
This plugin provides Keybase services to Helm.
ignoreFlags: false
useTunnel: false
command: "$HELM_PLUGIN_DIR/keybase.sh"
这样,就可以用 helm keybase
命令来使用这个插件。
Helm 命令参考
查询 charts
helm search
helm search mysql
查询 package 详细信息
helm inspect stable/mariadb
部署 package
helm install stable/mysql
部署之前可以自定义 package 的选项:
# 查询支持的选项
helm inspect values stable/mysql
# 自定义 password
echo "mysqlRootPassword: passwd" > config.yaml
helm install -f config.yaml stable/mysql
另外,还可以通过打包文件(.tgz)或者本地 package 路径(如 path/foo)来部署应用。
查询服务 (Release) 列表
➜ ~ helm ls
NAME REVISION UPDATED STATUS CHART NAMESPACE
quieting-warthog 1 Tue Feb 21 20:13:02 2017 DEPLOYED mysql-0.2.5 default
查询服务 (Release) 状态
➜ ~ helm status quieting-warthog
LAST DEPLOYED: Tue Feb 21 16:13:02 2017
NAMESPACE: default
STATUS: DEPLOYED
RESOURCES:
==> v1/Secret
NAME TYPE DATA AGE
quieting-warthog-mysql Opaque 2 9m
==> v1/PersistentVolumeClaim
NAME STATUS VOLUME CAPACITY ACCESSMODES AGE
quieting-warthog-mysql Bound pvc-90af9bf9-f80d-11e6-930a-42010af00102 8Gi RWO 9m
==> v1/Service
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
quieting-warthog-mysql 10.3.253.105 <none> 3306/TCP 9m
==> extensions/v1beta1/Deployment
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
quieting-warthog-mysql 1 1 1 1 9m
NOTES:
MySQL can be accessed via port 3306 on the following DNS name from within your cluster:
quieting-warthog-mysql.default.svc.cluster.local
To get your root password run:
kubectl get secret --namespace default quieting-warthog-mysql -o jsonpath="{.data.mysql-root-password}" | base64 --decode; echo
To connect to your database:
1. Run an Ubuntu pod that you can use as a client:
kubectl run -i --tty ubuntu --image=ubuntu:16.04 --restart=Never -- bash -il
2. Install the mysql client:
$ apt-get update && apt-get install mysql-client -y
3. Connect using the mysql cli, then provide your password:
$ mysql -h quieting-warthog-mysql -p
升级和回滚 Release
# 升级
cat "mariadbUser: user1" >panda.yaml
helm upgrade -f panda.yaml happy-panda stable/mariadb
# 回滚
helm rollback happy-panda 1
删除 Release
helm delete quieting-warthog
repo 管理
# 添加 incubator repo
helm repo add incubator https://kubernetes-charts-incubator.storage.googleapis.com/
# 查询 repo 列表
helm repo list
# 生成 repo 索引(用于搭建 helm repository)
helm repo index
chart 管理
# 创建一个新的 chart
helm create deis-workflow
# validate chart
helm lint
# 打包 chart 到 tgz
helm package deis-workflow
Helm UI
Kubeapps 提供了一个开源的 Helm UI 界面,方便以图形界面的形式管理 Helm 应用。
curl -s https://api.github.com/repos/kubeapps/kubeapps/releases/latest | grep -i $(uname -s) | grep browser_download_url | cut -d '"' -f 4 | wget -i -
sudo mv kubeapps-$(uname -s| tr '[:upper:]' '[:lower:]')-amd64 /usr/local/bin/kubeapps
sudo chmod +x /usr/local/bin/kubeapps
kubeapps up
kubeapps dashboard
更多使用方法请参考 Kubeapps 官方网站。
Helm Repository
官方 repository:
第三方 repository:
- https://github.com/coreos/prometheus-operator/tree/master/helm
- https://github.com/deis/charts
- https://github.com/bitnami/charts
- https://github.com/att-comdev/openstack-helm
- https://github.com/sapcc/openstack-helm
- https://github.com/helm/charts
- https://github.com/jackzampolin/tick-charts
常用 Helm 插件
- helm-tiller - Additional commands to work with Tiller
- Technosophos’s Helm Plugins - Plugins for GitHub, Keybase, and GPG
- helm-template - Debug/render templates client-side
- Helm Value Store - Plugin for working with Helm deployment values
- Drone.io Helm Plugin - Run Helm inside of the Drone CI/CD system