Appreciate the insight.  These are production RHEL7 servers, which I see
are based on sssd-1.16.5-xxx.  As in anything production, I am risk-adverse.

I'll just filter and move on.  Appreciate your help.

Spike

On Fri, Jun 23, 2023 at 9:02 AM Alexey Tikhonov <[email protected]> wrote:

> Hi,
>
>
> On Thu, Jun 22, 2023 at 7:52 PM Spike White <[email protected]>
> wrote:
>
>> Alexey,
>>
>> Thanks for the suggestion.
>>
>> This is a commercial application.  Cloudera's hadoop implementation.  No
>> idea if they use getgrouplist() under the hood.  I can ask our Cloudera
>> tech engineer, but I doubt he knows either.
>>
>> sssd-ad seems to work pretty well on these servers, except for these
>> occasional hiccups.  It's over 150 nodes in this hadoop cluster, with only
>> these occasional hiccups.  Been AD integrated for >1 yr and app team happy
>> (except for one annoying occasional cross-domain caching issue.)
>>
>> In particular, sssd finds its AD site so it's binding to AD DCs local to
>> this datacenter.  (I checked that first thing.)
>>
>> These sporadic hiccups I discuss earlier seem limited to local users
>> only, looking up their group memberships.
>>
>> Would the /etc/nsswitch.conf file syntax be:
>>
>>      initgroups:  files [SUCCESS=return] systemd sss
>>
>> It seems this would apply for all accounts that were members of local
>> groups and not just these specific accounts.  (Not sure that's a problem
>> for this particular app team, but I've seen AD accounts added in /etc/group
>> as members of local groups.)
>>
>> To me, "filter_users" in sssd.conf where I specify the specific accounts
>> would be safer.
>>
>
> Then filtering sounds as a way to go.
>
> If you are courageous you can also try to read SSSD logs to figure out the
> reason for those "sporadic hiccups".
> Latest version, around sssd-2.8+, should make it easier to track a
> specific lookup across a set of logs.
>
>
>
>>
>> Spike
>>
>> On Thu, Jun 22, 2023 at 10:44 AM Alexey Tikhonov <[email protected]>
>> wrote:
>>
>>> Hi,
>>>
>>> On Thu, Jun 22, 2023 at 4:47 PM Spike White <[email protected]>
>>> wrote:
>>>
>>>> All,
>>>>
>>>> Successful sssd consumer here.
>>>>
>>>> Have an app team running Hadoop.  They're getting these performance
>>>> errors in their app.
>>>>
>>>> This is from their app logs.
>>>>
>>>> ddlflhdm201.us.company.com
>>>> WARN June 15, 2023 10:08 AM Groups Potential performance problem:
>>>> getGroups(user=hbase) took 58022 milliseconds
>>>>
>>>
>>> Does it use `getgrouplist()` under the hood?
>>>
>>>
>>>> ddlflhdm304.us.company.com
>>>> WARN June 15, 2023 8:38 AM Groups Potential performance problem:
>>>> getGroups(user=mapred) took 39962 milliseconds
>>>> ddlplhdm505.us.company.com
>>>> WARN June 16, 2023 5:37 AM Groups Potential performance problem:
>>>> getGroups(user=hdfs) took 62437 milliseconds.
>>>> ddlplhdm305.us.company.com
>>>> WARN June 15, 2023 9:36 PM Groups Potential performance problem:
>>>> getGroups(user=hdfs) took 58017 milliseconds
>>>>
>>>> ddlplhdm505.us.company.com
>>>> WARN June 10, 2023 8:01 AM Groups Potential performance problem:
>>>> getGroups(user=yarn) took 58017 milliseconds.
>>>>
>>>>
>>>> Interestingly, all these users are local users created by the Hadoop
>>>> package installation.  (hbase, mapred, hdfs, yarn are all local users).
>>>>
>>>>
>>>> These local users are members only of local groups.  So theoretically
>>>> the search for group memberships should be lightning quick as the groups
>>>> are found only in /etc/group.
>>>>
>>>>
>>>> But since my /etc/nsswitch.conf looks like this:
>>>>
>>>>
>>>> passwd:     files systemd sss
>>>>
>>>> group:      files systemd sss
>>>>
>>>> netgroup:   files sss
>>>>
>>>> automount:  files sss
>>>>
>>>> services:   files
>>>>
>>>> shadow:     files sss
>>>>
>>>> hosts:      files dns myhostname
>>>>
>>>
>>> You might consider specifying 'initgroups' explicitly and using
>>> something like '[SUCCESS=return]' between databases to avoid going to sss
>>> altogether (but see below)
>>>
>>>>
>>>>
>>>> It not only searches local files for group membership, it searches AD
>>>> as well.  And doesn't find it, as there is no such AD user or uid.
>>>>  Eventually timing out.
>>>>
>>>>
>>>> In /var/log/messages we see this around the same time frame as
>>>>
>>>>
>>>> Jun 15 10:08:09 ddlflhdm201 sssd[be[amer.company.com]]: GSSAPI Error:
>>>> An invalid name was supplied (Success)
>>>>
>>>
>>> Is sssd-ad properly configured at this host?
>>> Initgroups lookup for unknown users should be fast.
>>>
>>>
>>>
>>>>
>>>> Is there a way to restrict these particular local app accounts from
>>>> having their group memberships looked up in AD?
>>>>
>>>> I.e., my [nss] section looks like this today:
>>>>
>>>> [nss]
>>>> #debug_level = 9
>>>> filter_groups = root
>>>> filter_users = root
>>>> #override_homedir = /home/%u
>>>>
>>>> Can I do this?
>>>>
>>>> [nss]
>>>> filter_users = root,  hbase, mapred, hdfs, yarn
>>>>
>>>> And would I want to set filter_users_in_groups = false?
>>>>
>>>> Spike White
>>>>
>>>>
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