Introduction

Epinio deploys applications on Kubernetes as Helm charts.

By default, a standard Helm chart is provided when Epinio is installed. However, operators may wish to create and register custom charts specific to their environment.

Once the custom charts are registered in Epinio, the developers can use them when deploying their applications as described in this How-to.

Listing the available Helm charts

You can list the available Helm charts by running the following command:

epinio app chart list

As an example, here is the output of an unmodified Epinio installation:

| DEFAULT |   NAME   |        DESCRIPTION         |
|---------|----------|----------------------------|
|         | standard | Epinio standard deployment |

The output will only list the standard Helm chart, which Epinio installs by default.

Deploying applications with a custom Helm chart

Use the option --app-chart to specify the name of the custom Helm chart to use when creating, updating, or deploying an application.

For detailed information on the --app-chart setting, see the following CLI commands pages:

• epinio app create
• epinio app update
• epinio push

caution

Changing the chart to use is not possible if the application has an active workload.

To switch a deployed application to a different Helm chart, you will have to delete and re-deploy the application.

info

Scaling the application to zero instances is not sufficient. While that effectively stops the application it does not remove the deployed workload, just the underlying active elements.

Deploying applications with a custom Helm chart which has user-settable configuration values

The general mechanism is the same as described in the previous section.

However, further use the option --chart-value to specify name and value of a single user-settable configuration value. Use the option multiple times to set all the desired configuration values.

note

User-settable configuration values are generally optional. The application chart is expected to contain and use sensible defaults for all configuration values not set by the user.

Example:

epinio push --name APPNAME --path APPSOURCEPATH --app-chart CHARTNAME --chart-value CVNAME=VALUE ...

Setting a default Helm chart

The --app-chart option described in the previous section is more suitable for single or few deployments requiring a custom Helm chart.

However, if the majority of applications use a specific custom chart, for example FOO, it makes more sense to change the default chart.

You can set a custom chart as the default by running the following command:

epinio app chart default FOO

Now, all future invocations of epinio push will use the custom Helm chart set as default. You will be able to override it with the --app-chart option, as described above.

note

The default chart is a local setting. It affects only the developer who made the change.

Querying the default Helm chart

You can check which chart is set as default by running the following command:

epinio app chart default

You can also check which chart is set as default when listing the available charts. As an example, the output below shows the chart FOO as the current default:

| DEFAULT |   NAME   |        DESCRIPTION         |
|---------|----------|----------------------------|
| *       | FOO      | Foofy deployment           |
|         | standard | Epinio standard deployment |

Unsetting the default Helm chart

You can set the system chart standard back as the default, by running the following command:

epinio app chart default ''

note

The empty string used in place of the chart name is mandatory. If you do not add it, the command will only list the charts available.