A user needs full read-only visibility into an ACI fabric. Which predefined security domain can be used to enable such visibility?

The `common` security domain only provides access to objects within the `common` tenant, not full visibility of the entire ACI fabric.

The `all` security domain in ACI is a special predefined domain that encompasses all objects across the entire ACI fabric, including all tenants, infrastructure, and common configurations. Assigning a read-only role to a user within the `all` security domain grants comprehensive viewing access to the entire system.

The `infra` security domain only provides access to objects within the `infra` tenant, which is limited to infrastructure-related configurations, not full fabric visibility.

While fabric-level roles exist, `fabric` is not a predefined security domain that grants full read-only visibility across the entire ACI fabric in the same way `all` does.