Usage of Helm and commands

helm_chart.txt

1. DIR1>helm create $chart
in the current dir, create a folder "chart" with structure
├── charts
├── Chart.yaml
├── templates
│   ├── deployment.yaml
│   ├── _helpers.tpl
│   ├── ingress.yaml
│   ├── NOTES.txt
│   ├── service.yaml
│   └── tests
│       └── test-connection.yaml
└── values.yaml


2. DIR1> helm lint $chart
check all syntax fine for the edit

3. DIR1>helm template $chart
it render $chart's template with values injected and show output to stdout

4. DIR1> helm package $chart
archieve folder $chart into a chart-version.tgz file
the folder's name need to match the inside Chart.yaml's "name" value

5. DIR1> helm repo index $chart --url https://nexus.mycompany.com/repository/helm_internal/
generate index.yaml file
or 
   DIR1> helm repo index  --merge index.yaml --url https://nexus.mycompany.com/repository/helm_internal/ $chart
merge a new chart info into existing index.yaml

6. DIR1>curl -u admin:adminpassword https://nexus.mycompany.com/repository/helm_internal/ --upload-file $chart-$version.tgz -v
use curl to update or use WEB GUI

helm_init.txt

By default, tiller installed in kub-system as deployment "tiller-deploy"
By default, tiller stores release information in ConfigMaps in the namespace where it is running, but now support to user Secrets

1.download helm from official release

2.untar it and put the binary helm into your path

3.> helm init 
which will create folder ~/.helm and sub folder and set this as a local repo  (just like ~/.docker put later added repo config into it)

  >helm version
to verify both client and tiller version

  >helm init --client-only will only condig helm not install tiller

when you have a new version helm just do >./helm init --upgrade to update tiller 

4. when you see "Error: incompatible versions client[v2.16.5] server[v2.14.1]" similarity
   >helm init --upgrade
   is need to upgrade tiller version to the same as the locla helm version

helm_install_delete.txt

A Chart is a Helm package
A Repository is the place where charts can be collected and shared
A Release is an instance of a chart running in a Kubernetes cluster
=>Helm installs charts into Kubernetes, creating a new release for each installation. And to find new charts, you can search Helm chart repositories.

3.>helm search $keyword [below 3.1.0 version]
  >helm search repo $keyword [3.1.0 and above]
show charts in the repo with keyword in chart's inspect keywords

4.>helm inspect values $chart
check config values for non-default chart installation can be used


5.>helm install [--set key1=nonStringValue1, key2=nonStringValue2 | --set-string key3=straingValue3 | -f value4.yaml] [--version $version] [ --name $name ] $chart [--debug --dry-run] [--timeout $time] [--tiller-namespace $tiller_namespace] [--namespace $release_namespace]
install chart from any of the repo available


value4.yaml is only the contents of customized values, no need to including default values
if use --debug --dry-run will only generated yaml file but not install
all the value set/pass from commandline will have the later one overwrite the previous one
if not use --version, it set to use latest one
by default timeout is 300s

--set foo=true results an int64 value. 
--set-string foo=true results in a string value of "true".

Examples of how to use set for different yaml and special cases:
--set key=value translate to yaml format 
key:value
---------
--set name="value1\,value2" will become:
name: "value1,value2"
---------
--set nodeSelector."kubernetes\.io/role"=master becomes
nodeSelector:
  kubernetes.io/role: master
----------
--set outer.inner=value is translated 
outer:
  inner: value
---------
--set key={v1, v2} translates to
key:
  - v1
  - v2
---------
--set servers[0].port=80,servers[0].host=example becomes:
servers:
  - port: 80
    host: example

There are five different ways you can express the chart you want to install:
By chart reference:                         helm install $repo/$chart
By path to a packaged chart:                helm install ./$mychart.tgz
By path to an unpacked chart directory:     helm install ./local_folder
By absolute URL:                            helm install https://example.com/charts/somechart.tgz
By chart reference and repo url:            helm install --repo https://example.com/charts/ $chart

6. >helm status $chart
do a check see if status is "deployed"

7. >helm get values $releaseName
show the values passed when helm install/upgrade set

8.> helm fetch $repo/$chart
this only download the chart/tgz

9.> helm inspect [--version $version] $repo/$chart
get all information including readme including yalm 
if not use --version, it set to use latest one

10.> helm list
list all currently deployed releases in the cluster
   >helm list --deleted
list all deleted release in the cluster
   >helm list --all
list all inlcuding deleted relases in the cluster

11.> helm delete $releasName
delete this release from cluster

12. >helm status $releaseName
do a check see if status is "deleted"

13. >helm upgrade -f my.yaml $releaseName $chart
upgrade to exisiting $releaseName with $chart' value.yaml but overwrite by my.yaml

helm_plugin.txt

Helm plugins can be added and removed from a Helm installation without impacting the core Helm tool.
They can be written in any programming language.
Helm plugins live in $(helm home)/plugins
├── plugin.yaml
├── exe.sh  (can be any name but need to be matching whats in plugin.yaml)
└── README.md

When Helm executes a plugin, it passes the outer environment to the plugin, and also injects some additional environment variables

1. >helm plugin install [$path|$url]
install a plugin either from local tgz file or from internet

2. >helm plugin list
list all the plugin installed

helm_repo.txt

1. >helm repo add dev https://example.com/dev-charts
Add a new repository, name as "dev" with url

2.> helm repo list
do a check you should see at least one local repo .
if you do not have problem to access  https://kubernetes-charts.storage.googleapis.com/index.yam

3.> helm repo update
update list of charts from above repo

helm_rollback.txt

1. >helm history $releaseName
check the release version. every install, upgrade, rollback, version increase 1


2. > helm rollback $releaseName [$version]
re-install release from cluster

hints

{{- (with the dash and space added) indicates that whitespace should be chomped left, while -}} means whitespace to the right should be consumed. Be careful! Newlines are whitespace!
if you want a new line, do not have - in front of }} on the previous line



It is considered preferable to use include over template in Helm templates simply so that the output formatting can be handled better for YAML documents.
While chart developers have a choice between include and template, one advantage of using include is that include can dynamically reference templates:
{{ include $mytemplate }}
The above will dereference $mytemplate. The template function, in contrast, will only accept a string literal

template.txt

 YAML files that have template directives embedded in {{  }}
 
 
 Release: This object describes the release itself. It has several objects inside of it:
    .Release.Name: The release name
    .Release.Time: The time of the release
    .Release.Namespace: The namespace to be released into (if the manifest doesn’t override)
    .Release.Service: The name of the releasing service (always Tiller).
    .Release.Revision: The revision number of this release. It begins at 1 and is incremented for each helm upgrade.
    .Release.IsUpgrade: This is set to true if the current operation is an upgrade or rollback.
    .Release.IsInstall: This is set to true if the current operation is an install.

 
 Values: Values passed into the template from the values.yaml file and from user-supplied files. By default, Values is empty
    The values.yaml file in the chart
    If this is a subchart, the values.yaml file of a parent chart
    A values file is passed into helm install or helm upgrade with the -f flag (helm install -f myvals.yaml ./mychart)
    Individual parameters passed with --set (such as helm install --set foo=bar ./mychart)

 
 
 Chart: The contents of the Chart.yaml file. Any data in Chart.yaml will be accessible here.
 
 Template: Contains information about the current template that is being executed
    Name: A namespaced filepath to the current template (e.g. mychart/templates/mytemplate.yaml)
    BasePath: The namespaced path to the templates directory of the current chart (e.g. mychart/templates).
    
    
    

tip.txt

>helm init --client-only --skip-refresh
if you do not want to connect your helm to tiller
if you do not have internet connection from your local till https://kubernetes-charts.storage.googleapis.com


without "helm init" there is no garantee that other helm command might work
e.g helm package

after upgrade helm from 2.16.3 to 3.1.2
old repo are gone, so need to helm add repo again