DOCS - Reporting configurable index custom user/roles

[elasticmachine]

Original comment by @kobelb:

When using Reporting with a custom index, the user is required to setup a custom user/role for this to work properly.

A similar situation applies when using a custom index for Kibana

/cc @alexfrancoeur

[tsullivan]

There's lots of examples in documentation for other stack products on how to do this, for example all the Beats, APM. This shouldn't be too hard to get done

[elasticmachine]

Pinging @elastic/kibana-reporting-services (Team:Reporting Services)

[legrego]

Custom roles are only required if the xpack.reporting.index setting does not start with .reporting-. The default Kibana system user has all privileges against the .reporting-* pattern of indices.

If you choose a custom reporting index, you can follow this naming convention to avoid creating custom roles.

Example: Custom reporting index following the pattern

xpack.reporting.index: '.reporting-custom-index'

The default Kibana system user already has the appropriate access to this index, so no further action is necessary.

Example: Custom reporting index not following the pattern

xpack.reporting.index: 'custom-reporting'

A new Kibana system user will need to be created, and assigned the kibana_system role, in addition to a new role with the all index privilege against the custom-reporting index, similar to the following:

Once created, Kibana should be configured to use this new account:

elasticsearch.username: 'custom_kibana_system'