On 3/3/13 10:12 AM, Yair Zaslavsky wrote:
----- Original Message -----
From: "Keith Mitchell" <kami...@cisco.com>
To: "Itamar Heim" <ih...@redhat.com>
Cc: "Yair Zaslavsky" <yzasl...@redhat.com>, users@ovirt.org, "Juan Antonio Hernandez
Fernandez" <jhern...@redhat.com>
Sent: Sunday, March 3, 2013 5:02:59 PM
Subject: Re: [Users] webadmin login issues with AD
On 3/3/13 8:37 AM, Itamar Heim wrote:
On 03/03/2013 15:26, Keith Mitchell wrote:
On 3/3/13 7:42 AM, Yair Zaslavsky wrote:
----- Original Message -----
From: "Keith Mitchell" <kami...@cisco.com>
To: "Yair Zaslavsky" <yzasl...@redhat.com>
Cc: users@ovirt.org, "Juan Antonio Hernandez Fernandez"
<jhern...@redhat.com>, "Itamar Heim" <ih...@redhat.com>
Sent: Sunday, March 3, 2013 2:28:38 PM
Subject: Re: [Users] webadmin login issues with AD
On 3/3/13 6:57 AM, Yair Zaslavsky wrote:
Please elaborate on "quite a few groups" - actually this is a
well
known issue.
I was afraid you might have permissions on "too many objects"
or
that the account is a member of too many groups.
However, being a member of too many groups should have caused
the
search to be slow/hang as well.
I don't have an exact count, but I think its along the order of
magnitude of 300-400.
Hi,
I gave an incorrect explanation before (I thought about it and
understood where my error lies ).
If I add a user using engine-manage-domains and do not provide
-addPermissions, I will still be able to login to the system
using
admin@internal, and perform search for users & groups.
This means I do not need to have permissions for the user I added
for
that domain to perform search so the "permissions" check is of
course
not performed at search!
The number of groups is important in login - oVirt will try to
calculate all the permissions of the users, and this is based on
the
permission the user have directly on an object, or that its group
has.
If the user is a member of 300 groups, oVirt tries to get
information
for all that groups.
THis is why login hands, but search does not hang.
I guess I don't understand why ovirt needs to do that. You should
be
able to get the list of groups a user is a member which I thought
was
sufficient for most apps to determine authorization.
I know we use AD authentication for a lot of things and i've never
hit
this before.
Changing the AD config isn't something I can do so it sounds like
there
is no workaround and i'll just have to live with the local
authentication. Or pehaps I can stick some ldap server in front
of
AD that
actually the issue is not getting the list of groups, rather than
ovirt is is checking which other groups these groups are part of,
to
make sure user gets the right permissions from nested groups as
well.
we didn't find an easy way to do this which doesn't involve looping
on
all the groups.
is this common for most users in your AD to have 300-400 groups?
Thanks,
Itamar
Yes, my case is fairly typical of our AD setup.
Not sure what other apps are doing here, but I do know that it
doesn't
take this long to get logged in :) Maybe they only look at direct
group
membership? Or they do things in reverse...
i.e. look up the groups in the access list to determine if the user
that
is authenticating can be found rather than traversing all the groups
a
user is a member of and trying to match all those groups to a group
(or
username) on the access list. That might run into the same issue if
the
group had lots of group members as opposed to user members.
Keith,
Not sure I understood this, can you please elaborate?
Say you configure ovirt so that 'groupa' has some permissions.
Rather than enumerating every group the user belongs to and comparing
the group name to one of the groups in the ovirt permissions list, we
would enumerate the groups in the ovirt permissions list and then search
for the authenticated user in those. Then you only have enumerate
groups that are actually used for authorization. I bet that there are
typically just a few groups used in the permissions list in a typical
deployment.
The current method also seems to want to query the server to get all
possible information and then make the decisions. Ideally you want to
do the fewest number of searches possible... and short circuit the
authorization algorithm as soon as sufficient data is gathered. One
common optimization is to compare all of the members of a group first
before you start recursing to optimize for the direct member case.
In my current case I just have my user listed in the permissions. It
should be able to fully authorize me without having to look at a single
one of the group memberships... here are no groups listed in ovirt so
all it really needs to do is match the user.
It was just a thought... I don't know much about the implementation of
ovirt... just what I saw in the network trace.
For my initial deployment, it looks like i'm going to have to just use
local authentication as this is just way to slow with our AD
infrastructure currently.
Changing the way the searches are made may speed up things too (if
thats
possible with the framework) to not reconnect for each search and to
do
multiple searches on the same connection. From my network capture
each
search request was taking about 1.5 seconds (from the bind request to
the unbind request).
Just some thoughts...
One of the things we tested is introducing ldap connection pooling.
Unfortunately, the current JDK implementation automatically turns off ldap
connection pooling if more than one domain is used.
Ravi, care to elaborate a bit on your findings?
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