Hi,

On Thu, Jun 22, 2023 at 4:47 PM Spike White <spikewhitetx@gmail.com> 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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