`test_tenant_relocation` ends up starting a temporary postgres instance with a fixed port. the change makes the port configurable at scripts/export_import_between_pageservers.py and uses that in test_tenant_relocation.
The 'local' part was always filled in, so that was easy to merge into
into the TimelineInfo itself. 'remote' only contained two fields,
'remote_consistent_lsn' and 'awaits_download'. I made
'remote_consistent_lsn' an optional field, and 'awaits_download' is now
false if the timeline is not present remotely.
However, I kept stub versions of the 'local' and 'remote' structs for
backwards-compatibility, with a few fields that are actively used by
the control plane. They just duplicate the fields from TimelineInfo
now. They can be removed later, once the control plane has been
updated to use the new fields.
This script can be used to migrate a tenant across breaking storage versions, or (in the future) upgrading postgres versions. See the comment at the top for an overview.
Co-authored-by: Anastasia Lubennikova <anastasia@neon.tech>
