Propose Magnum Resource Quota
There are multiple ways to slice an OpenStack cloud. Imposing quota on these various slices puts a limitation on the amount of resources that can be consumed by a project which helps to guarantee "fairness" or fair distribution of resource. If a particular project needs more resources, the concept of quota, gives the ability to increase the resource count on-demand, given that the system constraints are not exceeded. Change-Id: I6013057d689deb66a371adace96082df747f2b54 Partially-Implements: blueprint resource-quota
This commit is contained in:
Vilobh Meshram
parent
c85199072f
commit
5b37ba1643
254
specs/resource-quotas.rst
Normal file
254
specs/resource-quotas.rst
Normal file
@ -0,0 +1,254 @@
|
||||
..
|
||||
This work is licensed under a Creative Commons Attribution 3.0 Unported
|
||||
License.
|
||||
|
||||
http://creativecommons.org/licenses/by/3.0/legalcode
|
||||
|
||||
==========================
|
||||
Quota for Magnum Resources
|
||||
==========================
|
||||
|
||||
Launchpad blueprint:
|
||||
|
||||
https://blueprints.launchpad.net/magnum/+spec/resource-quota
|
||||
|
||||
There are multiple ways to slice an OpenStack cloud. Imposing quota on these
|
||||
various slices puts a limitation on the amount of resources that can be
|
||||
consumed which helps to guarantee "fairness" or fair distribution of resource
|
||||
at the creation time. If a particular project needs more resources, the
|
||||
concept of quota, gives the ability to increase the resource count on-demand,
|
||||
given that the system constraints are not exceeded.
|
||||
|
||||
|
||||
Problem description
|
||||
===================
|
||||
At present in Magnum we don't have the concept of Quota on Magnum resources as
|
||||
a result of which, as long as the underlying Infrastructure as a Service(IaaS)
|
||||
layer has resources, any user can consume as many resources as they want, with
|
||||
the hardlimit associated with the tenant/project being the upper bound for the
|
||||
resources to be consumed. Quotas are tied closely to physical resources and are
|
||||
billable entity and hence from Magnum's perspective it makes sense to limit the
|
||||
creation and consumption of a particular kind of resource to a certain value.
|
||||
|
||||
Use cases
|
||||
---------
|
||||
Alice is the admin. She would like to have the feature which will give her
|
||||
details of Magnum resource consumption so that she can manage her resource
|
||||
appropriately.
|
||||
|
||||
a. Ability to know current resource consumption.
|
||||
b. Ability to prohibit overuse by a project.
|
||||
c. Prevent situation where users in the project get starved because users in
|
||||
other project consume all the resource. Alice feels something like
|
||||
"Quota Management" would help to gurantee "fairness".
|
||||
d. Prevent DOS kind of attack, abuse or error by users where an excessive
|
||||
amount of resources are created.
|
||||
|
||||
Proposed change
|
||||
===============
|
||||
Proposed change is to introduce a Quota Table which will primarily store the
|
||||
quota assigned to each resource in a project. For Mitaka, we will restrict
|
||||
the scope to a Bay, which are Magnum resources. Primarily, as a first step we
|
||||
will start of by imposing quota on number of bays to be created in a project.
|
||||
The change also plans to introduce REST API's to GET/PUT/POST/DELETE. CLIs to
|
||||
get information of Quota for a particular project will also be provided.
|
||||
|
||||
For Mitaka, we will restrict the scope of the resources explicit created and
|
||||
managed by Magnum. Specifically for Mitaka we will focus on number of
|
||||
Bays only. Going ahead we might add Quota for containers, etc. The resources
|
||||
of which a Bay is constructed out of is inherently not only Magnum resource
|
||||
but involve resource from Nova, Cinder, Neutron etc. Limiting those resource
|
||||
consumption is out of the scope of this spec and needs a close collaboration
|
||||
with the quota management framework of the orchestration layer, since the
|
||||
orchestration layer can invoke the respective IaaS projects API's and get the
|
||||
consumption details before provisioning. As of now the orchestration layer
|
||||
used by Magnum, Heat, does not have the concept of Quota, so we will start with
|
||||
imposing Quota on resources which Magnum manages, Bay, more specifically for
|
||||
Mitaka.
|
||||
|
||||
When a project is created and if the Magnum service is running, the default
|
||||
quota for Magnum resources will be set by the values configured in magnum.conf.
|
||||
Other Openstack projects like Nova [3], Cinder [4] follow a similar pattern
|
||||
and we will also do so and hence won't have a seperate CLI for quota-create.
|
||||
Later if the user wants to change the Quota of the resource option will be
|
||||
provided to do so using magnum quota-update. In situation where all of the
|
||||
quota for a specific Magnum resource (Bay) have been consumed and is
|
||||
under use, admin will be allowed to set the quota to a any value lower than
|
||||
the usage or hardlimit to prohibit users from the project to create new
|
||||
Bays. This gives more flexibility to the admin to have a better control
|
||||
on resource consumption. Till the time the resource is not explicitly deleted
|
||||
the quota associated with the project, for a particular resource, won't be
|
||||
decreased. In short quota-update support will take into consideration the
|
||||
new hardlimit for a resource, specified by the admin, and will set the new
|
||||
value for this resource.
|
||||
|
||||
Before the resource is created, Magnum will check for current count of the
|
||||
resource(Bays) created for a project. If the resource(Bay) count is less
|
||||
than the hardlimit set for the Bay, new Bay creation will be allowed. Since
|
||||
Bay creation is a long running operation, special care will be taken while
|
||||
computing the available quota. For example, 'in-progress' field in the Quota
|
||||
usages table will be updated when the resource(Bay) creation is initiated and
|
||||
is in progress. Lets say the quota hardlimit is 5 and 3 Bay's have already been
|
||||
created and two new requests come in to create new Bays. Since we have 3 Bays
|
||||
already created the 'used' field will be set to 3. Now the 'in-progres'
|
||||
field will be set to 2 till the time the Bay creation is successful. Once
|
||||
the Bay creation is done this field will be reset to 0, and the 'used'
|
||||
count will be updated from 3 to 5. So at this moment, hardlimit is 5, used
|
||||
is 5 and in-progress is 0. So lets say one more request comes in to create
|
||||
new Bay this request will be prohibited since there is not enough quota
|
||||
available.
|
||||
|
||||
For Bays,
|
||||
|
||||
available = hard_limit - [in_progress + used]
|
||||
|
||||
In general,
|
||||
|
||||
Resource quota available = Resource hard_limit - [
|
||||
(Resource creation in progress + Resources already created for project)]
|
||||
|
||||
Alternatives
|
||||
------------
|
||||
At present there is not quota infrastructure in Magnum.
|
||||
|
||||
Adding Quota Management layer at the Orchestration layer, Heat, could be an
|
||||
alternative. Doing so will give a finer view of resource consumption at the
|
||||
IaaS layer which can be used while provisioning Magnum resources which
|
||||
depend on the IaaS layer [1].
|
||||
|
||||
Data model impact
|
||||
-----------------
|
||||
New Quota and Quota usages table will be introduced to Magnum database to
|
||||
store quota consumption for each resource in a project.
|
||||
|
||||
Quota Table :
|
||||
|
||||
+------------+--------------+------+-----+---------+----------------+
|
||||
| Field | Type | Null | Key | Default | Extra |
|
||||
+------------+--------------+------+-----+---------+----------------+
|
||||
| id | int(11) | NO | PRI | NULL | auto_increment |
|
||||
| created_at | datetime | YES | | NULL | |
|
||||
| updated_at | datetime | YES | | NULL | |
|
||||
| project_id | varchar(255) | YES | MUL | NULL | |
|
||||
| resource | varchar(255) | NO | | NULL | |
|
||||
| hard_limit | int(11) | YES | | NULL | |
|
||||
+------------+--------------+------+-----+---------+----------------+
|
||||
|
||||
Quota usages table :
|
||||
|
||||
+---------------+--------------+------+-----+---------+----------------+
|
||||
| Field | Type | Null | Key | Default | Extra |
|
||||
+---------------+--------------+------+-----+---------+----------------+
|
||||
| created_at | datetime | YES | | NULL | |
|
||||
| updated_at | datetime | YES | | NULL | |
|
||||
| id | int(11) | NO | PRI | NULL | auto_increment |
|
||||
| project_id | varchar(255) | YES | MUL | NULL | |
|
||||
| resource | varchar(255) | NO | | NULL | |
|
||||
| in_progress | int(11) | NO | | NULL | |
|
||||
| used | int(11) | NO | | NULL | |
|
||||
+---------------+--------------+------+-----+---------+----------------+
|
||||
|
||||
|
||||
REST API impact
|
||||
---------------
|
||||
REST API will be added for :
|
||||
|
||||
1. quota-defaults List all default quotas for all tenants.
|
||||
2. quota-show List the currently set quota values for a tenant.
|
||||
3. quota-update Updates quotas for a tenant.
|
||||
4. quota-usage Lists quota usage for a tenant.
|
||||
5. quota-list List quota for all the tenants.
|
||||
|
||||
A user with "admin" role will be able to do all the above operations but a user
|
||||
with "non-admin" role will be restricted to only get/list quota associated to
|
||||
his/her tenant. User with "non-admin" role can be a Member of the tenant less
|
||||
"admin" role.
|
||||
|
||||
REST API for resources which will have quota imposed will be enhanced :
|
||||
|
||||
1. Bay create
|
||||
Will check if there is quota available for Bay creation, if so proceed
|
||||
ahead with the request otherwise throw exception that not enough quota is
|
||||
available.
|
||||
|
||||
Security impact
|
||||
---------------
|
||||
None
|
||||
|
||||
Notifications impact
|
||||
--------------------
|
||||
None
|
||||
|
||||
Other end user impact
|
||||
---------------------
|
||||
End user will have the option to look at the quota set on the resources, quota
|
||||
usage by a particular project.
|
||||
|
||||
Performance Impact
|
||||
------------------
|
||||
None
|
||||
|
||||
Other deployer impact
|
||||
---------------------
|
||||
None
|
||||
|
||||
Developer impact
|
||||
----------------
|
||||
None
|
||||
|
||||
Implementation
|
||||
==============
|
||||
|
||||
Assignee(s)
|
||||
-----------
|
||||
|
||||
Primary assignee:
|
||||
vilobhmm
|
||||
|
||||
Other contributors:
|
||||
None
|
||||
|
||||
Work Items
|
||||
----------
|
||||
|
||||
1. Introduce Quota and Quota usages table in Magnum database.
|
||||
2. Introduce API to set/update Quota for a resource, specifically
|
||||
bay, for Mitaka release.
|
||||
3. Introduce API to create Quota entry, by default, for a resource.
|
||||
4. Provide config options that will allow users/admins to set Quota.
|
||||
5. Make sure that if the resource is deleted the used count from the
|
||||
quota_usages table will be decremented by the number of resources
|
||||
deleted. For example, if resource, bay, is deleted then the entries
|
||||
for it in the Quota usages table should be decremented by the
|
||||
number of Bays deleted.
|
||||
6. Provide CLI options to view the quota details :
|
||||
a. magnum quota-show <project-id>
|
||||
b. magnum quota-update <project-id> <resource> <hard-limit>
|
||||
c. magnum quota-defaults <project-id>
|
||||
d. magnum quota-usage <project-id>
|
||||
e. magnum quota-list
|
||||
7. Add conf setting for bays default quota since we will focus
|
||||
on Bays for Mitaka.
|
||||
|
||||
Dependencies
|
||||
============
|
||||
None
|
||||
|
||||
Testing
|
||||
=======
|
||||
|
||||
1. Each commit will be accompanied with unit tests.
|
||||
2. Gate functional tests will also be covered.
|
||||
|
||||
Documentation Impact
|
||||
====================
|
||||
None
|
||||
|
||||
References
|
||||
==========
|
||||
|
||||
[1] http://lists.openstack.org/pipermail/openstack-dev/2015-December/082266.html
|
||||
|
||||
[2] https://github.com/openstack/nova/blob/master/nova/quota.py
|
||||
|
||||
[3] https://github.com/openstack/nova/blob/master/cinder/quota.py
|
||||
Loading…
x
Reference in New Issue
Block a user