Open Metadata Archives

The open metadata archives provide pre-canned content (open metadata types and instances) to load into an open metadata repository. There are two main types of open metadata archive:

Figure 1 shows a content pack being loaded into a metadata repository. It is stored in the local repository and distributed around any connected cohorts. These types of archives can be provided by the Egeria community and third party organizations. Notice that due to the distribution of this metadata across the cohorts, it is only necessary to load the archive into one of the servers.

Figure 1

Figure 1: Loading a content pack

When data and other types of assets are being transported between organizations, it is possible to use a metadata export open metadata archive to pass the related metadata as well. This is shown in figure 2.

Figure 2

Figure 2: Exporting and reimporting metadata between unconnected repositories

Figure 3 shows a metadata export archive to create a backup of selected metadata. This can be used to recover the metadata repository content after a bad load or other operational error.

Figure 3

Figure 3: Selective back up of metadata elements

Creating open metadata archives

Open metadata archives are created through Java utilities. There are two approaches:

Loading open metadata archives

A metadata server’s configuration document can list the archives to load each time the server is started. This is useful if the server does not retain metadata through a server restart (like the in-memory metadata repository). Open metadata archives may also be loaded while the server is running using a REST API call.

The archive is loaded once and its content is immediately available. If the repository persists metadata over a server restart then this archive content continues to be available after the server restarts.

It does not matter how many times an archive is loaded, only one copy of the content is added to the repository.

These Administration Guide articles describe how to load open metadata archives into a server:

Inside an Open Metadata Archive

The open metadata archive has three parts to it. This is shown in Figure 4. The header defines the type of archive and its properties. Then there is the type store. This contains new types and updates to types (patches). Finally there is the instance store. This contains new instances (entities, relationships and classifications).

Figure 4

Figure 4: Inside an Open Metadata Archive

The archive loads in the following order:

More information about the design of the open metadata archives can be found in the Open Metadata Repository Services (OMRS) design documentation.

Supported utilities for open metadata archives

Egeria supports the following open metadata archives. Associated with each archive are utilities that help you build additional archives of your own content.

License: CC BY 4.0, Copyright Contributors to the ODPi Egeria project.