[SSSD-users] sssd troubles under load

Lukas Slebodnik lslebodn at redhat.com
Thu Jan 8 19:24:48 UTC 2015


On (08/01/15 19:54), Jakub Hrozek wrote:
>On Thu, Jan 08, 2015 at 09:31:16AM -0700, Orion Poplawski wrote:
>> On 01/06/2015 11:32 PM, Jakub Hrozek wrote:
>> > On Tue, Jan 06, 2015 at 05:06:39PM -0700, Orion Poplawski wrote:
>> >> We're having some trouble with sssd on centos 7 under load on a VPS. 389ds
>> >> ldap server for id/auth.  Part may be an issue with the VPS, but I'm trying
>> >> to track down all possible issues.
>> >>
>> >> Also, we realized that we were running in a bit of a bad state - the primary
>> >> ldap server was not available, but the backup was.
>> >>
>> >>  Some logs:
>> >>
>> >> General question, is this bad?:
>> >> (Tue Jan  6 23:17:43 2015) [sssd[be[default]]] [sdap_get_users_done]
>> >> (0x0040): Failed to retrieve users
>> > 
>> > This can be caused by many things, we neer more context..in general, the
>> > LDAP search has failed and SSSD would fall back to cached entries.
>> 
>> Okay, appears to be a simple "unknown user" type of response:
>> 
>> (Thu Jan  8 15:50:47 2015) [sssd[be[default]]] [be_get_account_info] (0x0100):
>> Got request for [4097][1][name=contracts-grants]
>> (Thu Jan  8 15:50:47 2015) [sssd[be[default]]] [sdap_get_users_done] (0x0040):
>> Failed to retrieve users
>> 
>> contracts-grants is not in LDAP.
>> > 
>> >>
>> >> see that fairly frequently.
>> >>
>> >> Trouble:
>> >> (Tue Jan  6 22:30:31 2015) [sssd[be[default]]]
>> >> [sss_ldap_init_sys_connect_done] (0x0020): sdap_async_sys_connect request
>> >> failed.
>> >> (Tue Jan  6 22:30:31 2015) [sssd[be[default]]] [sdap_sys_connect_done]
>> >> (0x0020): sdap_async_connect_call request failed.
>> >> (Tue Jan  6 22:30:36 2015) [sssd[be[default]]] [resolv_gethostbyname_done]
>> >> (0x0040): querying hosts database failed [5]: Input/output error
>> >> (Tue Jan  6 22:30:36 2015) [sssd[be[default]]] [fo_resolve_service_done]
>> >> (0x0020): Failed to resolve server 'server.com': Timeout while contacting
>> >> DNS servers
>> >> (Tue Jan  6 22:30:36 2015) [sssd[be[default]]] [be_resolve_server_process]
>> >> (0x0080): Couldn't resolve server (server.com), resolver returned (5)
>> > 
>> > This seems like the core issue, can you resolve server.com from outside
>> > SSSD (with dig, maybe) ?
>> 
>> In general, yes.  But it seems that some kind of load/network issue caused a
>> temporary failure.  We've since added entries to /etc/hosts to try to prevent
>> this from happening again.
>> 
>> > 
>> >> (Tue Jan  6 22:30:45 2015) [sssd[be[default]]]
>> >> [sss_ldap_init_sys_connect_done] (0x0020): sdap_async_sys_connect request
>> >> failed.
>> >> (Tue Jan  6 22:30:45 2015) [sssd[be[default]]] [sdap_sys_connect_done]
>> >> (0x0020): sdap_async_connect_call request failed.
>> >> (Tue Jan  6 22:30:45 2015) [sssd[be[default]]] [fo_resolve_service_send]
>> >> (0x0020): No available servers for service 'LDAP'
>> >> (Tue Jan  6 22:30:45 2015) [sssd[be[default]]] [sdap_id_op_connect_done]
>> >> (0x0020): Failed to connect, going offline (5 [Input/output error])
>> >> (Tue Jan  6 22:30:45 2015) [sssd[be[default]]] [be_run_offline_cb] (0x0080):
>> >> Going offline. Running callbacks.
>> > 
>> > Here SSSD goes offline and the front end would switch to using the
>> > cache.
>> 
>> 
>> >> (Tue Jan  6 22:33:08 2015) [sssd[be[default]]] [get_single_value_as_string]
>> >> (0x0080): More than one value found.
>> >> (Tue Jan  6 22:33:08 2015) [sssd[be[default]]]
>> >> [sdap_set_config_options_with_rootdse] (0x0020): get_naming_context failed.
>> >> (Tue Jan  6 22:33:14 2015) [sssd[be[default]]] [get_single_value_as_string]
>> >> (0x0080): More than one value found.
>> > 
>> > This is weird as well, here SSSD is complaining that defaultNamingContext
>> > attribute of rootDSE contains multiple values. But I don't see SSSD grabbing
>> > the rootDSE anywhere at all..what log level did you use?
>> 
>> Log level 3
>> 
>> > 
>> > You can read the rootDSE manually using:
>> > ldapsearch -x -H ldap://server.com -s base -b "" defaultNamingContext
>> 
>> # extended LDIF
>> #
>> # LDAPv3
>> # base <> with scope baseObject
>> # filter: (objectclass=*)
>> # requesting: defaultNamingContext
>> #
>> 
>> #
>> dn:
>> 
>> # search result
>> search: 2
>> result: 0 Success
>> 
>> # numResponses: 2
>> # numEntries: 1
>> 
>> I've now added a defaultnamingcontext.
>> 
>
>Did it cause any difference? 
>
>I wouldn't expect a missing defaultNamingContext to be fatal for SSSD..
Some LDAP servers use "defaultNamingContext" other "namingContexts".
SSSD uses available one.

LS


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