github.com/y-taka-23/helm@v2.8.0+incompatible/docs/chart_best_practices/conventions.md (about)

     1  # General Conventions
     2  
     3  This part of the Best Practices Guide explains general conventions.
     4  
     5  ## Chart Names
     6  
     7  Chart names should be lower case letters and numbers. Words _may_ be separated with dashes (-):
     8  
     9  Examples:
    10  
    11  ```
    12  drupal
    13  nginx-lego
    14  aws-cluster-autoscaler
    15  ```
    16  
    17  Neither uppercase letters nor underscores should be used in chart names. Dots should not be used in chart names.
    18  
    19  The directory that contains a chart MUST have the same name as the chart. Thus, the chart `nginx-lego` MUST be created in a directory called `nginx-lego/`. This is not merely a stylistic detail, but a requirement of the Helm Chart format.
    20  
    21  ## Version Numbers
    22  
    23  Wherever possible, Helm uses [SemVer 2](http://semver.org) to represent version numbers. (Note that Docker image tags do not necessarily follow SemVer, and are thus considered an unfortunate exception to the rule.)
    24  
    25  When SemVer versions are stored in Kubernetes labels, we conventionally alter the `+` character to an `_` character, as labels do not allow the `+` sign as a value.
    26  
    27  ## Formatting YAML
    28  
    29  YAML files should be indented using _two spaces_ (and never tabs).
    30  
    31  ## Usage of the Words Helm, Tiller, and Chart
    32  
    33  There are a few small conventions followed for using the words Helm, helm, Tiller, and tiller.
    34  
    35  - Helm refers to the project, and is often used as an umbrella term
    36  - `helm` refers to the client-side command
    37  - Tiller is the proper name of the backend
    38  - `tiller` is the name of the binary run on the backend
    39  - The term 'chart' does not need to be capitalized, as it is not a proper noun.
    40  
    41  When in doubt, use _Helm_ (with an uppercase 'H').
    42  
    43  ## Restricting Tiller by Version
    44  
    45  A `Chart.yaml` file can specify a `tillerVersion` SemVer constraint:
    46  
    47  ```yaml
    48  name: mychart
    49  version: 0.2.0
    50  tillerVersion: ">=2.4.0"
    51  ```
    52  
    53  This constraint should be set when templates use a new feature that was not
    54  supported in older versions of Helm. While this parameter will accept sophisticated
    55  SemVer rules, the best practice is to default to the form `>=2.4.0`, where `2.4.0`
    56  is the version that introduced the new feature used in the chart.
    57  
    58  This feature was introduced in Helm 2.4.0, so any version of Tiller older than
    59  2.4.0 will simply ignore this field.