Nova
Revision as of 17:35, 17 June 2010 by (talk)
Nova Cloud Review
The purpose of this document is to capture the pluses and minuses of using Nova's code as a part of Cloud servers v2
Glossary
- Public API Servers - Know as "Nucleus" in cloud servers v1 or "Cloud Controller" in Eucalyptus.
- Pod - A group of physical host nodes. Known as "QB" in cloud server v1 or "Cluster Controller" in Eucalyptus.
- Host - Individual physical host in a Pod.
- Guest - VM instance running on a host.
What's Done
- Scalable and elastic architecture - fully message based and asynchronous
- Many months ahead of us
- Written in good Python
- Open source and it appears that they will be following an open development model. update: Based on the issue tracker, I am not sure this is true
- Have stubbed out all components for testing
- Actually write SSH keys and authorized_keys properly
- openldap based authentication and authorization
- All functionality is created via an adapter model, so implementations (for instance, storage backends, messaging backends, etc) can be swapped out as needed
What Needs to be Done
- Create a layer inside Nova that would be able to distinguish between different pods
- Currently, the CloudController class in /endpoints/cloud.py represents a mixture of a public API server and a pod controller
- The CloudController class receives public API requests and sends messages to the nodes to perform actions
- Separate out the receipt and translation of public API requests to a separate APIServer class
- Separate out the transmission of private action messages to a PodController class
- Currently, the CloudController class in /endpoints/cloud.py represents a mixture of a public API server and a pod controller
- Detach from Amazon/Eucalyptus specifics and make some things more generic
- API: We need to add the Rackspace API, and a caching layer
- It is not reasonable for us to use the Amazon API, we would be unable to innovate and would constantly be catch up
- We would also need to add a distinct API for each service we layer on top, so they can be used with either the ec2 or rackspace API's
- API: We need to add the Rackspace API, and a caching layer
- AOE
- Definitely needs to be adapted for other services like CloudFiles, gluster, etc
- Defaults of VLANs could be changed
- though you can manually allocate IPs or use DHCP (see /compute/network.py)
- Functionality needed by hosting providers
- Metrics
- CPU, memory, disk usage, network RX/TX
- but, again, the backend storage is already taken care of...
- Metrics
- Billing
- Need to define the billable events in a model
- Admin client is AWS-specific and needs an adapter interface
- see /adminclient.py
- Overarching documentation is sparse (though the code comments are pretty decent)
- twisted (and Python) is, by nature, single-core, so it *may* be a bottleneck, but that remains to be demonstrated
- No support for gluster or drbd, but there are adapters for plugging such functionality into the app domain
- Add an endpoint so different compute clusters can be discovered for different clusters, especially when distributed geographically.
- Configuration management is almost non-existent
- Need to plugin/adapt the configuration retrieval
- Puppet, Chef, or even a DKVS
- The "flavors" are hardcoded in /compute/node.py (grep for INSTANCE_TYPES)
- While there is decent unittest coverage, there is no real systems testing or documentation of plans for one
- There would need to be a good chunk of code written to automate the testing of pod deployments, the testing of network partitions, and more
- Cleanup and refactoring of the Keeper function (datastore.py) and its adaptor pattern
Image Support
- Only supports AMIs, we should add OVA support
- Requires use of euca2ools, which are tainted, we need a set of ova tools and possibly a clean room rewrite of the AMI tools, if we care
- There is one global bucket in S3 called _images (hardcoded)
- Needs to be segmented and enhanced to support public, private, and shared images (i.e. support customer_id)
- Support for image storage in Cloud Files
- Support for image caching at the node level, ala iback
Unknowns
- Asked jm to take a looksie into any possible Windows issues with the code base (in using Windows as a host with Hyper-V? Not sure what this means)
- We know that ssh keys will not work with windows, so another method is necessary