On 12 September 2017 at 17:59, John Beranek wrote:
> On 11 September 2017 at 14:28, Jakub Hrozek wrote:
>> On Mon, Sep 11, 2017 at 12:23:26PM +0100, John Beranek wrote:
>>> On 1 September 2017 at 15:54, Lukas Slebodnik wrote:
>>> >
>>> > On (01/09/17 09:33), William Edsall wrote:
>>> > >Had a few communications with Michal but we're still stuck.
>>> > >
>>> > >One issue is that we have dozens of domain controllers globally. A 
>>> > >standard
>>> > >dns lookup could give me a domain controller overseas which will be slow,
>>> > >or maybe even a domain controller that isn't responding. As such, I have
>>> > >been inserting ad_server = x into the sssd.conf to improve performance.
>>> > >
>>> > >I noticed that if I do not insert ad_server = x, I'm getting different
>>> > >results. My initial id request is very slow but seems to produce results.
>>> > >While searching, it seems to also be 'inserting' users into the users 
>>> > >hash
>>> > >table - almost as if it's searching and inserting our entire user 
>>> > >database?
>>> > >For example there are countless lines of the following:
>>> > >(Fri Sep  1 09:28:37 2017) [sssd[be[example.com]]]
>>> > >[sdap_nested_group_hash_insert] (0x4000): Inserting
>>> > >[CN=user_name,OU=bla,OU=bla Users,DC=dow,DC=com] into hash table [users]
>>> > >
>>> > >As my initial id request returns, it seems to return several chunks of my
>>> > >group ids at once as if it's processing them individually and searching 
>>> > >all
>>> > >users in that group (thus the above log entries).
>>> > >
>>> > >Not sure if this helps or just muds up the issue but it's strange indeed.
>>> > >
>>> > You needn't hardcode ad_server. You can still rely on dns discovery.
>>> > I assume you use sites in AD. So you can "pin" sssd to your local/nearest 
>>> > site
>>> > with option ad_site.
>>>
>>> I've got something to add to this, some behaviour we're seeing with
>>> CentOS 7 servers using sssd-ad.
>>>
>>> sssd-1.14.0-43.el7_3.18.x86_64
>>> sssd-ad-1.14.0-43.el7_3.18.x86_64
>>> sssd-client-1.14.0-43.el7_3.18.x86_64
>>> sssd-common-1.14.0-43.el7_3.18.x86_64
>>> sssd-common-pac-1.14.0-43.el7_3.18.x86_64
>>> sssd-ipa-1.14.0-43.el7_3.18.x86_64
>>> sssd-krb5-1.14.0-43.el7_3.18.x86_64
>>> sssd-krb5-common-1.14.0-43.el7_3.18.x86_64
>>> sssd-ldap-1.14.0-43.el7_3.18.x86_64
>>> sssd-proxy-1.14.0-43.el7_3.18.x86_64
>>>
>>> In our case we have some DCs which are located at a partner site, and
>>> are therefore inaccessible to clients on our standard LANs.
>>>
>>> When SSSD starts it will correctly determine there are 2 primary DCs
>>> (these are the ones for the site) and 7 backup DCs.
>>>
>>> However, what is happening from time to time is that for some reason
>>> I've not yet determined the connection(s) to the primary DC(s) are
>>> dropping, and then sssd attempts to connect to one of the DCs that are
>>> inaccessible.
>>>
>>> In what circumstances would sssd prefer a backup server to a primary server?
>>>
>>> I've got a chunk of log which I've anonymised:
>>>
>>> https://paste.fedoraproject.org/paste/G69lC9COQfbnWFI~qtFLZw
>>
>> The issue is here:
> [snip]
>>
>> So this is a known bug where locating the site (even though we know it
>> already) can contact the DCs outside that site.
>>
>> In the meantime, until the fix is released, you can hardcode the site
>> using the 'ad_site' option.
>
> Thank you Jakub, is there a ticket/BZ for this? I noticed after my
> post that it's evident on CentOS 6 too.

Ah, https://pagure.io/SSSD/sssd/issue/3265 ?

John

-- 
John Beranek                         To generalise is to be an idiot.
http://redux.org.uk/                                 -- William Blake
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