207 lines
5.6 KiB
ReStructuredText
Executable File
207 lines
5.6 KiB
ReStructuredText
Executable File
..
|
|
This work is licensed under a Creative Commons Attribution 3.0 Unported
|
|
License.
|
|
|
|
http://creativecommons.org/licenses/by/3.0/legalcode
|
|
|
|
==========================================
|
|
Compute Driver Interface
|
|
==========================================
|
|
https://blueprints.launchpad.net/octavia/+spec/compute-driver-interface
|
|
|
|
This blueprint describes how a driver will interface with Nova to
|
|
manage the creation and deletion of amphora instances. It will
|
|
describe the base class and other classes required to create, delete,
|
|
manage the execution state, and query the status of amphorae.
|
|
|
|
Problem description
|
|
===================
|
|
The controller needs to be able to create, delete, and monitor the
|
|
status of amphora instances. The amphorae may be virtual machines,
|
|
containers, bare-metal servers, or dedicated hardware load balancers.
|
|
This interface should hide the implementation details of the amphorae
|
|
from the caller to the maximum extent possible.
|
|
|
|
This interface will provide means to specify:
|
|
- type (VM, Container, bare metal)
|
|
- flavor (provides means to specify memory and storage capacity)
|
|
- what else?
|
|
|
|
Proposed change
|
|
===============
|
|
Establish an abstract base class to model the desired functionality:
|
|
|
|
.. code:: python
|
|
|
|
class AmphoraComputeDriver(object):
|
|
|
|
def build(self, amphora_type = VM, amphora_flavor = None,
|
|
image_id = None, keys = None, sec_groups = None,
|
|
network_ids = None,config_drive_files = None,user_data=None):
|
|
|
|
""" build a new amphora.
|
|
|
|
:param amphora_type: The type of amphora to create. For
|
|
version 0.5, only VM is supported. In the future this
|
|
may support Container, BareMetal, and HWLoadBalancer.
|
|
:param amphora_flavor: Optionally specify a flavor. The
|
|
interpretation of this parameter will depend upon the
|
|
amphora type and may not be applicable to all types.
|
|
:param image_id: ID of the base image for a VM amphora
|
|
:param keys: Optionally specify a list of ssh public keys
|
|
:param sec_groups: Optionally specify list of security
|
|
groups
|
|
:param network_ids: A list of network_ids to attach to
|
|
the amphora
|
|
:config_drive_files: A dict of files to overwrite on
|
|
the server upon boot. Keys are file names (i.e. /etc/passwd)
|
|
and values are the file contents (either as a string or as
|
|
a file-like object). A maximum of five entries is allowed,
|
|
and each file must be 10k or less.
|
|
:param user_data: user data to pass to be exposed by the
|
|
metadata server this can be a file type object as well or
|
|
a string
|
|
|
|
:returns: The id of the new instance.
|
|
|
|
"""
|
|
|
|
raise NotImplementedError
|
|
|
|
def delete(self, amphora_id):
|
|
""" delete the specified amphora
|
|
"""
|
|
|
|
raise NotImplementedError
|
|
|
|
def status(self, amphora_id):
|
|
|
|
""" Check whether the specified amphora is up
|
|
|
|
:param amphora_id: the ID of the desired amphora
|
|
:returns: the nova response from the amphora
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
def get_amphora(self, amphora_name = None, amphora_id = None):
|
|
""" Try to find an amphora given its name or id
|
|
|
|
:param amphora_name: the name of the desired amphora
|
|
:param amphora_id: the id of the desired amphora
|
|
:returns: the amphora object
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
Exception Model
|
|
---------------
|
|
|
|
The driver is expected to raise the following well defined exceptions:
|
|
|
|
* NotImplementedError - this functionality is not implemented/not supported
|
|
* AmphoraComputeError - a super class for all other exceptions and the catch
|
|
all if no specific exception can be found
|
|
|
|
* AmphoraBuildError - An amphora of the specified type could
|
|
not be built
|
|
* DeleteFailed - this amphora couldn't be deleted
|
|
|
|
* InstanceNotFoundError - an instance matching the desired criteria
|
|
could not be found
|
|
* NotSuspendedError - resume() attempted on an instance that was not suspended
|
|
|
|
|
|
|
|
Things a good driver should do:
|
|
-------------------------------
|
|
|
|
* Non blocking operations - If an operation will take a long time to execute,
|
|
perform it asynchronously. The definition of "a long time" is open to
|
|
interpretation, but a common UX guideline is 200 ms
|
|
* We might employ a circuit breaker to insulate driver
|
|
problems from controller problems [1]
|
|
* Use appropriate logging
|
|
* Use the preferred threading model
|
|
|
|
This will be demonstrated in the Noop-driver code.
|
|
|
|
|
|
Alternatives
|
|
------------
|
|
|
|
|
|
Data model impact
|
|
-----------------
|
|
None
|
|
|
|
|
|
REST API impact
|
|
---------------
|
|
None
|
|
|
|
|
|
Security impact
|
|
---------------
|
|
None
|
|
|
|
|
|
Notifications impact
|
|
--------------------
|
|
None - since initial version
|
|
|
|
|
|
Other end user impact
|
|
---------------------
|
|
None
|
|
|
|
|
|
Performance Impact
|
|
------------------
|
|
Minimal
|
|
|
|
|
|
Other deployer impact
|
|
---------------------
|
|
Deployers need to make sure to bundle the compatible
|
|
versions of amphora, driver, controller --
|
|
|
|
|
|
Developer impact
|
|
----------------
|
|
Need to write towards this clean interface.
|
|
|
|
|
|
Implementation
|
|
==============
|
|
|
|
Assignee(s)
|
|
-----------
|
|
Al Miller
|
|
|
|
Work Items
|
|
----------
|
|
* Write abstract interface
|
|
* Write Noop driver
|
|
* Write tests
|
|
|
|
|
|
Dependencies
|
|
============
|
|
None
|
|
|
|
|
|
Testing
|
|
=======
|
|
* Unit tests with tox and Noop-Driver
|
|
* tempest tests with Noop-Driver
|
|
|
|
|
|
Documentation Impact
|
|
====================
|
|
None - this is an internal interface and need not be externally
|
|
documented.
|
|
|
|
|
|
References
|
|
==========
|
|
[1] http://martinfowler.com/bliki/CircuitBreaker.html
|