[Freeipa-users] LDAP server failover via altServer attribute?

[Guillermo Fuentes]

SRV record failover works for Kerberos on the Mac. Setting "dns_lookup_kdc
= yes" and removing the KDC server ("kdc = xxx") entries from the
/Library/Preferences/edu.mit.Kerberos config file does the trick.

For LDAP, although you can enable it, I can't see it documented anywhere so
I'm assuming that isn't the recommended way for the Mac. This can be
enabled by running this for the LDAP server you're using:
sudo odutil set configuration /LDAPv3/ipa1.example.com module ldap option
"Use DNS replicas" "true"

Adding the altServer values with the Directory Manager credentials worked
and I'm happy to report that the failover on the Mac works great with
FreeIPA!

As suggested by Rob, for three servers, on server ipa1:
$ ldapmodify -x -D 'cn=directory manager' -W
Enter LDAP Password:
dn:
changetype: modify
add: altServer
altServer: ldap://ipa2.example.com
-
add: altServer
altServer: ldap://ipa3.example.com

modifying entry ""
^D

The altServer values didn't replicate so I had to add them to each of the
FreeIPA servers.

Then, tell the Mac (testing on OS X v10.11.5) to use the altServer
attribute to look for replicas in case of failover:
sudo odutil set configuration /LDAPv3/ipa1.example.com module ldap option
"Use altServer replicas" "true"

And, viola! Highly available authentication with a FreeIPA cluster for the
Mac!

Thanks so much for your help!
Guillermo


On Fri, May 20, 2016 at 10:38 AM, Rob Crittenden <rcritten at redhat.com>
wrote:

> Martin Basti wrote:
>
>> Hello,
>>
>> IPA uses SRV records for failover to another replica/LDAP.
>>
>> I don't know how it works on MACs, but in case that there is no
>> possibility to use SRV, you may need to file a RFE ticket
>> (https://fedorahosted.org/freeipa/newticket)
>>
>
> Agreed, SRV records are the preferred mechanism. I was curious though so
> played with this a bit and it is possible to add altServer values:
>
> $ ldapmodify -x -D 'cn=directory manager' -W
> Enter LDAP Password:
> dn:
> changetype: modify
> add: altServer
> altServer: ldap://gyre.example.com
>
> modifying entry ""
> ^D
>
> $ ldapsearch -LLL -x -b "" -s base altServer
> dn:
> altServer: ldap://gyre.example.com
>
> My test rig is a single master so I don't know if this replicates or not.
>
> rob
>
>
>> Martin
>>
>>
>> On 19.05.2016 17:43, Guillermo Fuentes wrote:
>>
>>> Hello all,
>>>
>>> As OS X allows LDAP server failover via the altServer attribute
>>> (RFC4512) from RootDSE, it would be great to be able to configure our
>>> Macs to connect to a single FreeIPA server and add other FreeIPA
>>> servers as multiple altServer values.
>>> The current schema doesn't seem to support adding this attribute.
>>> Can this be done in a way I'm missing?
>>>
>>> Thanks in advance!
>>>
>>> GUILLERMO FUENTES
>>> SR. SYSTEMS ADMINISTRATOR
>>>
>>> 561-880-2998 x1337
>>>
>>> guillermo.fuentes at modmed.com <mailto:guillermo.fuentes at modmed.com>
>>>
>>>
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>>
>>
>>
>
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