Using custom application Helm charts
Epinio deploys applications on Kubernetes as Helm charts.
By default, a standard Helm chart is provided at Epinio installation time. However, operators may wish to create and register custom charts specific to their environment.
After developers have registered custom charts in Epinio, developers can use them when deploying their applications as described here.
Listing the available Helm charts​
You can list the available Helm charts by running the following command:
epinio app chart list
For example, this is the output of an unmodified Epinio installation:
| DEFAULT | NAME | DESCRIPTION |
|---------|----------|----------------------------|
| | standard | Epinio standard deployment |
The output only lists 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:
Changing the chart to use isn't possible if the application has an active workload.
To switch a deployed application to a different Helm chart, you have to delete and re-deploy the application.
Scaling the application to zero instances isn't enough. While that stops the application it doesn't 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 earlier section.
However, use the option --chart-value to specify name and value of a single user-settable configuration value.
Use the option as many times as needed to set all the desired configuration values.
For example:
epinio push --name APPNAME --path APPSOURCEPATH --app-chart CHARTNAME --chart-value CVNAME=VALUE ...
User-settable configuration values are usually optional. The application chart should contain sensible defaults for all configuration values not set by the user.
Setting a default Helm chart​
The --app-chart option described in the earlier section is more suitable for single
or a small number requiring a custom Helm chart.
However, if most 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 uses the custom Helm chart set as default.
You can override it with the --app-chart option, described above.
The default chart is a local setting. It affects only the local developer's environment.
Querying the default Helm chart​
You can check which chart is the default by running the following command:
epinio app chart default
You can check which chart is the default when listing the available charts.
For example, the output below shows the chart FOO as the current default:
| DEFAULT | NAME | DESCRIPTION |
|---------|----------|----------------------------|
| * | FOO | Foofy deployment |
| | standard | Epinio standard deployment |
Reset to the default Helm chart​
You can set the system chart standard back as the default, by running the following command:
epinio app chart default ''
You need the empty string used in place of the chart name. If you don't add it, the command only lists the charts available.