[Kimchi-devel] [RFC] LDAP integration in kimchi

[Zhou Zheng Sheng]

on 2014/10/15 11:07, Royce Lv wrote:
> On 2014年10月14日 21:03, Aline Manera wrote:
>>
>> On 10/14/2014 03:59 AM, Royce Lv wrote:
>>> On 2014年10月14日 01:15, Aline Manera wrote:
>>>>
>>>> On 10/13/2014 03:43 AM, Royce Lv wrote:
>>>>> LDAP supports connect to it (bind) for authentication,
>>>>> usr/group/role add/delete for authorization.
>>>>> For kimchi-LDAP integration we need to address following issues:
>>>>>
>>>>> 1. LDAP set up scripts for kimchi:
>>>>> We need to add initial users: guest, admin; roles: netadmin,
>>>>> hostadmin, guestadmin in LDAP server.
>>>>> Adding these schema for user maybe a burden, we may supply a script
>>>>> to init LDAP server configuration
>>>>>
>>>>
>>>> We should be able to work with LDAP setup as it is, ie, without
>>>> requiring any special configuration in the LDAP server for it.
>>>> Today we only have 2 types of users: admin (with full access) and
>>>> normal user (with restricted access).
>>>> Later, when we support more type of users who will assign roles to
>>>> users will be the admin users.
>>>> Example: I am a "admin" user and I give you admin privileges to the
>>>> network tab. I hope to have an UI for it. So user can assign roles
>>>> to users in the UI. (But it is for later)
>>>>
>>>> So my suggestion is have a list of admin IDs in the Kimchi
>>>> configuration file when the authentication method is LDAP.
>>>> Example:
>>>>
>>>> On /etc/kimchi.conf we will have:
>>>>
>>>> [authentication]
>>>> method = ldap | pam
>>>>
>>>> For LDAP method we will have addition config parameters:
>>>>
>>>> # For LDAP authentication
>>>> ldap_server = ""
>>>> ldap_search_base = ""
>>>> ldap_search_filter = "mail=%(username)s"
>>>> ldap_admin_users = "alinefm at linux.vnet.ibm.com
>>>> lvroyce at linux.vnet.ibm.com"
>>>>
>>>> So after the logging we verify the user against the ldap_admin_users
>>>> to know if this specific user has or not admin privileges.
>>>> That way, we can support login using LDAP and also identify what are
>>>> the admin users without special configuration in the LDAP server.
>>> Well, I still think there are some advantages of using dedicate LDAP
>>> for authentication and authorization.
>>>
>>> 1. If this LDAP is not for kimchi role maintainence, it can just
>>> cover authentication not authorization.
>>
>> Yeap. I think that is the point we are diverging.
>>
>> We will use LDAP server *only for authentication*.
>> Authorization will be handle by Kimchi - in a similar way we do for
>> PAM authentication.
>>
>>> Authorization as you listed above spread over hosts, making role
>>> maintenance difficult.
>>> Thinking about a cluster of hosts, if you want add an admin like
>>> alinefm at br.ibm.com, you change every config in these hosts.
>>
>> It will be part of the Kimchi configuration.
>>
>>>
>>> 2. Not convenient for role extension
>>> If you want to levels like: virtualzation_admin(can create/destroy
>>> vm), guest_admin(can start/stop vm),guest_user(can use vm)
>>> We need to extend this configuration and this need kimchi upgrade
>>> while keep it in LDAP you just add LDAP schema.
>>>
>>
>> Thinking about PAM authentication: when we support more user roles,
>> the map user/role will be store internally on Kimchi - let's say on
>> objectstore.
>> So we will provide some APIs to an admin user set/change an user role.
>> We can do the same for LDAP authentication.
>>
>>> Also openstack-keystone both have dedicate LDAP to maintain its
>>> users/roles.
>>> http://www.ibm.com/developerworks/cloud/library/cl-ldap-keystone/index.html
>>>
>>>
>>>
>>> I suggest we aggregate authorization and authentication as they do
>>> for extendibility and integrity of functionality.
>>
>> We don't need to integrate both to have functional setup.
>> As I said before, we will handle Kimchi authorization inside Kimchi
>> for PAM or LDAP authentication as it is only related to Kimchi and a
>> LDAP server has more proposal than it.
> 
> Why do we do for our own (use objstore to store role/group) which LDAP
> already be able to cover?
> 
> LDAP is extensible if we have a cluster to maintain, put authorization
> in configuration totally lose this extensibility, admin need to change
> configuration hosts one by one,
> which objstore also does not able to handle this extendibility.
> 
> I can't say this approach brings us/users any benefit.
> Also take a look at openstack, why we can't use the method they already
> verified to be effective?

I have some comments for your consideration.

Kimchi is a small project targeting for
small/testing/development/on-ramp use case, that is to say, Kimchi
should be polite and noninvasive to the environment. Kimchi has to
prepare itself to co-exist with other tools. OpenStack is a huge project
union which dominates the environment. So not everything that OpenStack
can do is what Kimchi also can do. Agree?

A company may already have an ldap setup in production, for evaluating
Kimchi, the admin may neither want to change the ldap configuration nor
give write access to Kimchi. Kimchi may only read the ldap to do
authentication. For example, suppose you are in a company named BigBlur
;-), and BigBlur has an ldap containing all the staff information. This
ldap is under control of a world wide team, and the fields are fixed.
Now a guy in Beijing lab wants to use Kimchi to manage 4 hosts, and he
wants to use BigBlur ldap to allow only some of his colleagues to use
Kimchi. If Kimchi has to store extended information in ldap, just
considering how complicated the process is to communicate with the ldap
team, he may just give up ldap and use PAM...

I agree to Aline's suggestion. Kimchi can use an outside ldap just to
authenticate users. Kimchi can use an inside objectstore to store the
authorization matrix, and the groups. This gives us the flexibility to
use any authorization scheme, for example, though you and me might be
peers in BigBlur's ldap, but you can be the admin and I can be the user
in Kimchi. This is just like how Jenkins-ci uses ldap.

As regard to the multi-host configuration problem, I think now that we
already have peer discovering, we may also have configuration
synchronization. For example, when a new Kimchi host is up, the user can
"import" the authentication matrix from the other Kimchi host.

>>
>>>>
>>>>
>>>>>
>>>>> 2. Configuration of using LDAP:
>>>>> Configured to use PAM/LDAP, Connecting to a dedicate LDAP server
>>>>> address(As we may use an LDAP to store information of clustered
>>>>> machine, address can be modified).
>>>>> If this LDAP server does not exist, ask user if they want to setup
>>>>> one, and help them with setup scripts.
>>>>> For this release just support one LDAP per host.
>>>>>
>>>>
>>>> No!
>>>> The LDAP must be setup prior to use it as Kimchi authentication method.
>>>> LDAP configuration is a system admin responsibility.
>>> user may not a LDAP professional and schema writing may be error prone.
>>
>> The user can choose between PAM and LDAP. I don't expect to have
>> non-LDAP expert using this type of authentication.
>>
>>>>
>>>>> 3. Module for LDAP operation wrapping:
>>>>> A dedicate module to encapsulate LDAP operations, such as
>>>>> bind/unbind, adding, deleting, query groups/roles.
>>>>
>>>> I will not add/delete user from a LDAP directory.
>>> See above.
>>>>
>>>>>
>>>>> 4. authentication:
>>>>> We need to abstract authenticate class to be compatible with both
>>>>> PAM and LDAP, and call bind/unbind to implement authentication.
>>>>>
>>>>> 5. authorization:
>>>>> Abstract authentication module to distiguish PAM and LDAP, user
>>>>> name still from cherrypy session, when using LDAP, user/role
>>>>> information are all retrieved from LDAP server.
>>>>>
>>>>
>>>> The username will get from the LDAP server but it is not true for
>>>> user role as I explained above.
>>>>
>>>>> 6. user/role maintenance:
>>>>> Manipulate LDAP to add user, delete user, authorize user with a
>>>>> role, add role/delete role, and so on.
>>>>> This part will not be covered in this release.
>>>>
>>>> No! We will not add/delete any information from the LDAP directory.
>>>> We will only use it for query proposals.
>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Kimchi-devel mailing list
>>>>> Kimchi-devel at ovirt.org
>>>>> http://lists.ovirt.org/mailman/listinfo/kimchi-devel
>>>>>
>>>>
>>>> Other point that is important is: how set a user/group to a VM?
>>>> On UI, for PAM authentication, we list all users and groups and let
>>>> user selects which he/she wants to user.
>>>> This approach is unfeasible for a LDAP perspective.
>>> If group design for control of a set of vms or resources(views)?
>>
>> To control vms - which users and groups will have access to a specific vm
>>
>>>>
>>>> The users, from a LDAP perspective, will be the user mail, for
>>>> example, so in this case we could only provide the user a filter box
>>>> and list the available matches in the LDAP server.
>>>>
>>>> For groups, the values will come from LDAP search base and filter ?
>>> That is why I want dedicate LDAP for authorization,
>>> groups/roles/users all supplied.
>>> If we just have user, we need to suplement this part in another data
>>> store, I suppose.
>>
>> The authorization will be handle in the same way for PAM or LDAP
>> authentication, ie, store it internally on Kimchi using objectstore or
>> other type of data structure.
>>
>>>>
>>>> We need to find a good and consistent way to do that independent of
>>>> the authentication method to make the UI simpler.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>