Samba AD schema extensions
Schema Extension in Samba Active Directory
Samba AD supports the same kind of schema extensions as Microsoft Active Directory. Schema updates in AD are a sensitive action and you must be prepared to do a full restore of the DC holding the role of schema master if something goes wrong.
This is even more true in Samba 4 given it does not always generate some critical attributes that are generated on Microsoft AD and this lack of attributes can lead to a un-start-able samba provision. This is why schema updates in Samba AD are currently disabled by default.
In order to allow them, the option dsdb:schema update allowed must be set to true in the smb.conf or passed on the command line.
Verified Schema Extensions
As getting an LDIF that won't ruin the provision can be hard, this page will list LDIFs that are known not to break the database.
Perform these updates only if you need them and if you know how to restore the provision on the schema master.
This extension allow you to store automount information in LDAP. In order to add this extension, follow these steps:
- Download Automount_template.ldif.txt, this is a template that will be transformed in the next steps
- Locate the rootDN of your provision: ldbsearch -H ldap://ip_of_server -U administrator -s base dn
- Run cat automount_template.ldif | sed 's/DOMAIN_TOP_DN/value_of_rootDN_obtained_in_previous_step/' > automount.ldif
- Split the resulting file into two, one containing the attributes, the other containing the objectclasses
- Name the two new files automount_attrs.ldif and automount_classes.ldif
- Stop Samba4 on the schema master
- Copy automount_attrs.ldif and automount_classes.ldif to the schema master server (if you were working on a different server)
- Apply the ldifs with commands similar to:
- ldbmodify -H path_to_sam_ldb automount_attrs.ldif --option="dsdb:schema update allowed"=true
- ldbmodify -H path_to_sam_ldb automount_classes.ldif --option="dsdb:schema update allowed"=true
Building your own schema extensions
- You will need an OID. Ideally your organisation or company has an OID arc, or you are converting an existing schema
- This will be the
Internal use and experimental Samba OIDs
22.214.171.124.4.1.7165.777.1.X is reserved in Samba for use by Samba installations internally.
If you use a OID from this range, please note your use below. 126.96.36.199.4.1.7165.777.2.X
Syntax for attributes
- See Microsoft's Documentaion on choosing a syntax
- You need to choose the Syntax ID
attributeSyntax(eg 188.8.131.52), Samba will map that to the and OM ID (eg 4) for you.
- Decide if this will be
TRUEor by default
- You need a clear, ideally globally unique, name for your attribute or class, this will be the
- Consider re-using names from [schema.org schema.org] if there is no existing example for LDAP
- LDAP schema are traditionally camalCase with a lowercase initial letter