Many saved object types were converted in Kibana 8.0, so they can eventually be shared across spaces. Before 8.0, you could have two objects with the same type and same ID in two different spaces. Part of this conversion is to make sure all object IDs of a given type are globally unique across all spaces.

Kibana creates a special entity called a legacy URL alias for each saved object that requires a new ID. This legacy URL alias allows Kibana to preserve any deep link URLs that exist for these objects.

Consider the following scenario:

You have Kibana 7.16, and you create a new dashboard.The ID of this dashboard is "123". You create a new space called "Bill’s space" and copy your dashboard to the other space. Now you have two different dashboards that can be accessed at the following URLs:

You use these two dashboards frequently, so you bookmark them in your web browser. After some time, you decide to upgrade to Kibana 8.0. When these two dashboards go through the conversion process, the one in "Bill’s space" will have its ID changed to "456". The URL to access that dashboard is different — not to worry though, there is a legacy URL alias for that dashboard.

If you use your bookmark to access that dashboard using its old URL, Kibana detects that you are using a legacy URL, and finds the new object ID. If you navigate to http://localhost:5601/s/bills-space/app/dashboards#/view/123, you’ll see a message indicating that the dashboard has a new URL, and you’re automatically redirected to http://localhost:5601/s/bills-space/app/dashboards#/view/456.

Legacy URL aliases are intended to be fully transparent, but there are rare situations where this can lead to an error. For example, you might have a dashboard and one of the visualizations fails to load, directing you to this page. If you encounter an error in this situation, you might want to disable the legacy URL alias completely. This leaves the saved object intact, and you will not lose any data — you just won’t be able to use the old URL to access that saved object.

To disable a legacy URL alias, you need three pieces of information: the targetSpace, the targetType, and the sourceId. Then use the _disable_legacy_url_aliases API to disable the problematic legacy URL alias.