github.com/zoumo/helm@v2.5.0+incompatible/docs/chart_template_guide/values_files.md (about)

     1  # Values Files
     2  
     3  In the previous section we looked at the built-in objects that Helm templates offer. One of the four built-in objects is `Values`. This object provides access to values passed into the chart. Its contents come from four sources:
     4  
     5  - The `values.yaml` file in the chart
     6  - If this is a subchart, the `values.yaml` file of a parent chart
     7  - A values file if passed into `helm install` or `helm update` with the `-f` flag (`helm install -f myvals.yaml ./mychart`)
     8  - Individual parameters passed with `--set` (such as `helm install --set foo=bar ./mychart`)
     9  
    10  The list above is in order of specificity: `values.yaml` is the default, which can be overridden by a parent chart's `values.yaml`, which can in turn be overridden by a user-supplied values file, which can in turn be overridden by `--set` parameters.
    11  
    12  Values files are plain YAML files. Let's edit `mychart/values.yaml` and then edit our ConfigMap template.
    13  
    14  Removing the defaults in `values.yaml`, we'll set just one parameter:
    15  
    16  ```yaml
    17  favoriteDrink: coffee
    18  ```
    19  
    20  Now we can use this inside of a template:
    21  
    22  ```yaml
    23  apiVersion: v1
    24  kind: ConfigMap
    25  metadata:
    26    name: {{ .Release.Name }}-configmap
    27  data:
    28    myvalue: "Hello World"
    29    drink: {{ .Values.favoriteDrink }}
    30  ```
    31  
    32  Notice on the last line we access `favoriteDrink` as an attribute of `Values`: `{{ .Values.favoriteDrink}}`.
    33  
    34  Let's see how this renders.
    35  
    36  ```console
    37  $ helm install --dry-run --debug ./mychart
    38  SERVER: "localhost:44134"
    39  CHART PATH: /Users/mattbutcher/Code/Go/src/k8s.io/helm/_scratch/mychart
    40  NAME:   geared-marsupi
    41  TARGET NAMESPACE:   default
    42  CHART:  mychart 0.1.0
    43  MANIFEST:
    44  ---
    45  # Source: mychart/templates/configmap.yaml
    46  apiVersion: v1
    47  kind: ConfigMap
    48  metadata:
    49    name: geared-marsupi-configmap
    50  data:
    51    myvalue: "Hello World"
    52    drink: coffee
    53  ```
    54  
    55  Because `favoriteDrink` is set in the default `values.yaml` file to `coffee`, that's the value displayed in the template. We can easily override that by adding a `--set` flag in our call to `helm install`:
    56  
    57  ```
    58  helm install --dry-run --debug --set favoriteDrink=slurm ./mychart
    59  SERVER: "localhost:44134"
    60  CHART PATH: /Users/mattbutcher/Code/Go/src/k8s.io/helm/_scratch/mychart
    61  NAME:   solid-vulture
    62  TARGET NAMESPACE:   default
    63  CHART:  mychart 0.1.0
    64  MANIFEST:
    65  ---
    66  # Source: mychart/templates/configmap.yaml
    67  apiVersion: v1
    68  kind: ConfigMap
    69  metadata:
    70    name: solid-vulture-configmap
    71  data:
    72    myvalue: "Hello World"
    73    drink: slurm
    74  ```
    75  
    76  Since `--set` has a higher precedence than the default `values.yaml` file, our template generates `drink: slurm`.
    77  
    78  Values files can contain more structured content, too. For example, we could create a `favorite` section in our `values.yaml` file, and then add several keys there:
    79  
    80  ```yaml
    81  favorite:
    82    drink: coffee
    83    food: pizza
    84  ```
    85  
    86  Now we would have to modify the template slightly:
    87  
    88  ```
    89  apiVersion: v1
    90  kind: ConfigMap
    91  metadata:
    92    name: {{ .Release.Name }}-configmap
    93  data:
    94    myvalue: "Hello World"
    95    drink: {{ .Values.favorite.drink }}
    96    food: {{ .Values.favorite.food }}
    97  ```
    98  
    99  While structuring data this way is possible, the recommendation is that you keep your values trees shallow, favoring flatness. When we look at assigning values to subcharts, we'll see how values are named using a tree structure.
   100  
   101  At this point, we've seen several built-in objects, and used them to inject information into a template. Now we will take a look at another aspect of the template engine: functions and pipelines.