MidoNet is a system which implements an abstract, software-defined virtual network atop an existing IP fabric. That means that packets that enter a MidoNet deployment will then leave it at the location and with the alterations they would have had if they'd actually traversed the networking equipment defined in the deployment's virtual topology, or as close to it as we can manage.
A MidoNet deployment consists a few kinds of nodes, all connected in an IP network. Many nodes run Midolman, and are where traffic enters and leaves. Traffic is sent from its entry point (the ingress node) to its exit point (the egress node) via tunnels; see the tunnel management document. The network's virtual topology and associated information is stored in ZooKeeper, and per-connection state which is shared between nodes is stored in Cassandra -- all the Midolman nodes which compose a virtual network must have connectivity to the ZooKeeper and Cassandra clusters, as that's how they coordinate. The web-based REST API described here is provided by nodes running MidoNet's API service in a webserver. These API server nodes will read and modify the virtual topology configuration, so they need to have connectivity to the ZooKeeper cluster, but not necessarily any other node types.
All patches to MidoNet are submitted to Gerrit, an open source, web-based code review system. It's publicly hosted on GerritHub, and integrated with a CI infrastructure based on Jenkins that runs several suites of automated tests.
To submit a patch, you'll need to sign into GerritHub using your GitHub
account and set up your ssh-key in Settings->SSH public keys
. If you
need information to set up git review, or git-review workflows, please
check MidoNet Developer's Guide in the wiki.
Submitting a review is simple, typically:
git clone https://github.com/midonet/midonet
git checkout -b your_branch origin/master
# .. make some changes ..
git commit -as # commit your changes, and sign off your commit
git review master
Your review will now appear on GerritHub. After committers approve your change and the code is tested, it'll get merged into the main repository.
Feel free to join other MidoNet developers at #midonet-dev on irc.freenode.net, or our the Development mailing list. We'll be happy to help you get set up.
The MidoNet project is split into several submodules:
This contains the various pieces that compose each of the nodes in
Midonet's distributed controller (brain
). Controller nodes take care
of orchestrating the configuration of all Midonet subcomponents, as well
as coordinating with other external devices and systems, such as VTEP
switches, the backend services holding our Network State DataBase (e.g:
Zookeeper and Cassandra), etc.
This holds basic classes for parsing, building, and manipulating packets of various network protocol types.
Contains basic utilities used by the other modules, and is described here.
Contains the MidoNet edge controller code, as described here.
Contains the implementation of the MidoNet REST API.
Code for speaking the netlink protocol over a netlink socket, generally for communicating with the OS kernel.
Code for interacting (receiving notifications and sending commands) to the kernel's Open Datapath module.
Most dependencies are pulled in by the gradle build scripts, however there are some prerequisites:
- java 7 jdk
- protobufs compiler
- Install 2.6.1 from here
- fpm (ruby gem) to build debian/rpm packages
- rpm
The brain
directory contains an odl-ovsdb git submodule with code that
must be compiled in order to generate dependencies needed in various
midonet components. Before any build tasks, ensure that you have the
right version of odl-ovsdb by executing:
~/midonet$ git submodule update --init --recursive
~/midonet$ ./gradlew
This will build all the modules while running all the tests from all the modules. To skip the tests, you can run the command:
~/midonet$ ./gradlew -x test
The build script provides targets to build debian and rpm packages. In all cases packages will be found in midolman/build/packages/ and midonet-api/build/packages.
Building debian packages:
~/midonet$ ./gradlew debian -x test
RPM packages targeted for RHEL 6.5:
~/midonet$ ./gradlew rpm -x test
RHEL 7 packages:
~/midonet$ ./gradlew rpm -x test -PrhelTarget=7
On ubuntu this requires the rpm tools which you can install with
# apt-get install rpm
~/midonet$ ./gradlew test