Security and roles v4
Beyond basic package installation and configuration, HARP requires Postgres permissions to operate. These allow it to gather information about Postgres or BDR as needed to maintain node status in the consensus layer.
Postgres permissions
Create the role specified in the node.dsn parameter in one
of the following ways:
CREATE USER ...CREATE ROLE ... WITH LOGIN
This syntax ensures the role can log into the database to gather diagnostic information.
Similarly, an entry must exist in pg_hba.conf for this role. You can do this in
many ways. As an example, consider a VPN subnet where all database hosts are
located somewhere in 10.10.*. In such a case, the easiest approach is to add
a specific line:
# TYPE DATABASE USER ADDRESS METHOD hostssl all harp_user 10.10.1.1/16 scram-sha-256
Note
In this case we've used the more modern scram-sha-256 authentication
rather than md5, which is now deprecated. We've also elected to require
SSL authentication by specifying hostssl.
BDR permissions
BDR nodes have metadata and views that are visible only when certain roles are granted to the HARP-enabled user. In this case, the HARP user requires the following:
GRANT bdr_monitor TO harp_user;
The bdr_monitor BDR role is meant for status monitoring tools to maintain
ongoing information on cluster operation, thus it is well-suited to HARP.
BDR consensus permissions
When the dcs.driver configuration parameter is set to bdr, HARP
uses BDR as the consensus layer. As such, it requires access to API
methods that are currently available only to the bdr_superuser role. This
means the HARP-enabled user requires the following:
GRANT bdr_superuser TO foobar;
Currently access to the BDR consensus model requires superuser equivalent permission.
Important
BDR superusers are not Postgres superusers. The bdr_superuser role is
merely granted elevated privileges in BDR, such as access to
restricted functions, tables, views, and other objects.