* To describe working configurations of OpenStack (which code branches work together? what do config files look like for those branches?)
* To make it easier for developers to dive into OpenStack so that they can productively contribute without having to understand every part of the system at once
IMPORTANT: Be sure to carefully read `stack.sh` and any other scripts you execute before you run them, as they install software and may alter your networking configuration. We strongly recommend that you run `stack.sh` in a clean and disposable vm when you are first getting started.
The devstack master branch generally points to trunk versions of OpenStack components. For older, stable versions, look for branches named stable/[release] in the DevStack repo. For example, you can do the following to create a diablo OpenStack cloud:
You can also pick specific OpenStack project releases by setting the appropriate `*_BRANCH` variables in `localrc` (look in `stackrc` for the default set). Usually just before a release there will be milestone-proposed branches that need to be tested::
You can override environment variables used in `stack.sh` by creating file name `localrc`. It is likely that you will need to do this to tweak your networking configuration should you need to access your cloud from a different host.
Apache web server is enabled for wsgi services by setting `APACHE_ENABLED_SERVICES` in your localrc. But remember to enable these services at first as above.
devstack supports adding specific Neutron configuration flags to the service, Open vSwitch plugin and LinuxBridge plugin configuration files. To make use of this feature, the following variables are defined and can be configured in your `localrc` file:
devstack also supports configuring the Neutron ML2 plugin. The ML2 plugin can run with the OVS, LinuxBridge, or Hyper-V agents on compute hosts. A simple way to configure the ml2 plugin is shown below:
# VLAN configuration
Q_PLUGIN=ml2
ENABLE_TENANT_VLANS=True
# GRE tunnel configuration
Q_PLUGIN=ml2
ENABLE_TENANT_TUNNELS=True
# VXLAN tunnel configuration
Q_PLUGIN=ml2
Q_ML2_TENANT_NETWORK_TYPE=vxlan
The above will default in devstack to using the OVS on each compute host. To change this, set the `Q_AGENT` variable to the agent you want to run (e.g. linuxbridge).
Q_AGENT This specifies which agent to run with the ML2 Plugin (either `openvswitch` or `linuxbridge`).
Q_ML2_PLUGIN_MECHANISM_DRIVERS The ML2 MechanismDrivers to load. The default is none. Note, ML2 will work with the OVS and LinuxBridge agents by default.
Q_ML2_PLUGIN_TYPE_DRIVERS The ML2 TypeDrivers to load. Defaults to all available TypeDrivers.
Q_ML2_PLUGIN_GRE_TYPE_OPTIONS GRE TypeDriver options. Defaults to none.
Q_ML2_PLUGIN_VXLAN_TYPE_OPTIONS VXLAN TypeDriver options. Defaults to none.
Q_ML2_PLUGIN_VLAN_TYPE_OPTIONS VLAN TypeDriver options. Defaults to none.
Q_AGENT_EXTRA_AGENT_OPTS Extra configuration options to pass to the OVS or LinuxBridge Agent.
You likely want to change your `localrc` to run a scheduler that will balance VMs across hosts:
SCHEDULER=nova.scheduler.simple.SimpleScheduler
You can then run many compute nodes, each of which should have a `stackrc` which includes the following, with the IP address of the above controller node:
Be aware that there are some features currently missing in cells, one notable one being security groups. The exercises have been patched to disable functionality not supported by cells.