Ubuntu Server Guide

server guide has incorrect information for sync replication

Bug #1844463 reported by Quanah
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Ubuntu Server Guide
Fix Released
Undecided
Andreas Hasenack

Bug Description

The following guide has information on how to configure delta-sync replication with OpenLDAP, but has a few issues https://help.ubuntu.com/lts/serverguide/openldap-server.html

a) This modification is incorrect:

# syncrepl Provider for primary db
dn: olcOverlay=syncprov,olcDatabase={1}mdb,cn=config
changetype: add
objectClass: olcOverlayConfig
objectClass: olcSyncProvConfig
olcOverlay: syncprov
olcSpNoPresent: TRUE

As noted in the slapo-syncprov(5) man page, setting NOPRESENT to TRUE is only valid on an accesslog databse NOT the primary database. The valid options for the primary database are the checkpoint and sessionlog options

b) The guide makes no mention of setting a proper sessionlog value for the syncprov overlay. This is critical for avoiding a known bug in sync replication (https://www.openldap.org/its/index.cgi/?findid=8125). It's generally mandatory that the sessionlog be no less than, and preferably larger, than the total number of entries in the primary database.

c) The guide uses the rootdn for the replication configuration. This is not the recommended way to set up replication in OpenLDAP and can cause issues. A replication specific DN that is NOT a rootdn should be used for replication instead.

Thanks!

Regards,
Quanah

Revision history for this message
Andreas Hasenack (ahasenack) wrote :

Thanks for filing this. We are updating the server guide for the next LTS, and I linked this bug to that section.

Changed in serverguide:
status: New → Confirmed
Revision history for this message
Andreas Hasenack (ahasenack) wrote :

Ideally the existing guide will also be fixed, of course.

Andreas Hasenack (ahasenack)
Changed in serverguide:
assignee: nobody → Andreas Hasenack (ahasenack)
status: Confirmed → In Progress
Revision history for this message
Andreas Hasenack (ahasenack) wrote :

Ok, I believe I addressed these issues in the source at https://discourse.ubuntu.com/t/service-ldap-replication/15508

Its publication to the official docs is automated, but I don't have the rendered link at hand right now.

Revision history for this message
Andreas Hasenack (ahasenack) wrote :

Ah, it's here: https://ubuntu.com/server/docs

Changed in serverguide:
status: In Progress → Fix Released
Revision history for this message
Andreas Hasenack (ahasenack) wrote :

I don't know how to mark the 18.04 guide as still affected by this bug, but the current guide is fix-released now.

Revision history for this message
Andreas Hasenack (ahasenack) wrote :

I still want to add the simpler syncrepl case, the non-delta one, to the guide.

Revision history for this message
Doug Smythies (dsmythies) wrote :

You, and others, have done a lot for the new discourse version of the serverguide. thanks so much.

There is no hope of keeping up with the back porting of stuff to the docbook 18.04 version. So will no longer add the "target to series" split on these bug reports.

After a 18.04 serverguide point release a few hours ago, I closed the 2 from the when the split out of the discource source occurred before the launchpad source was branched.

Revision history for this message
Doug Smythies (dsmythies) wrote :

The page was not linked in the url mapping table on the introduction page, so the reader would still end up at the discourse source page.
It is linked now.

https://ubuntu.com/server/docs/service-ldap-replication

(I thought I had checked them all a few days ago, but must have missed this one.)

Revision history for this message
Andreas Hasenack (ahasenack) wrote :

You didn't miss it, it's a new page I created yesterday. Sorry *I* missed the link in the introduction page.

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