HELM #

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Helm is the best way to find, share, and use software built for Kubernetes.

官网：https://helm.sh

Helm is a tool for managing Charts. Charts are packages of pre-configured Kubernetes resources.

Use Helm to:

Find and use popular software packaged as Helm Charts to run in Kubernetes
Share your own applications as Helm Charts
Create reproducible builds of your Kubernetes applications
Intelligently manage your Kubernetes manifest files
Manage releases of Helm packages

基本概念 #

Chart：一个 Helm 包，其中包含了运行一个应用所需要的镜像、依赖和资源定义等，还可能包含 Kubernetes 集群中的服务定义，
- Chart 是用来封装 Kubernetes 原生应用程序的一系列 YAML 文件集合
- 类似
  - Homebrew 中的 formula
  - apt 的 dpkg
  - yum/dnf 的 rpm
Repository：用于发布和存储 Chart 的存储库。
Release：在 Kubernetes 集群上运行的 Chart 的一个实例。在同一个集群上，一个 Chart 可以安装很多次。每次安装都会创建一个新的 release。例如一个 MySQL Chart，如果想在服务器上运行两个数据库，就可以把这个 Chart 安装两次。每次安装都会生成自己的 Release，会有自己的 Release 名称。
Tiller 是 Helm2 的服务端，通常运行在您的 kubernetes 集群中。Tiller 用于接收 Helm 的请求，并根据 Chart 生成 Kubernetes 的部署文件，然后提交给 Kubernetes 创建应用。
- HElm3 中删除了 Tiller，只有客户端使用，调用 ~/.kube/config 来访问 api server 进行创建

命令 #

  completion  generate autocompletions script 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

开源镜像 #

BurdenBear/kube-charts-mirror #

# 删除默认的源
helm repo remove stable
helm repo remove incubator

# 增加新的国内镜像源
helm repo add stable http://mirror.azure.cn/kubernetes/charts/

helm repo add incubator http://mirror.azure.cn/kubernetes/charts-incubator/

helm repo list

helm search repo mysql

TODO #

# Initialize a Helm Chart Repository
$ helm repo add stable https://kubernetes-charts.storage.googleapis.com/

# list the charts you can install
$ helm search repo stable

# Install an Example Chart
$ helm repo update
$ helm install stable/mysql --generate-name
NAME: mysql-1596179301
LAST DEPLOYED: Fri Jul 31 15:08:27 2020
NAMESPACE: default
STATUS: deployed
REVISION: 1
NOTES:
MySQL can be accessed via port 3306 on the following DNS name from within your cluster:
mysql-1596179301.default.svc.cluster.local

To get your root password run:

    MYSQL_ROOT_PASSWORD=$(kubectl get secret --namespace default mysql-1596179301 -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 mysql-1596179301 -p

To connect to your database directly from outside the K8s cluster:
    MYSQL_HOST=127.0.0.1
    MYSQL_PORT=3306

    # Execute the following command to route the connection:
    kubectl port-forward svc/mysql-1596179301 3306

    mysql -h ${MYSQL_HOST} -P${MYSQL_PORT} -u root -p${MYSQL_ROOT_PASSWORD}