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DevStack is a set of scripts and utilities to quickly deploy an OpenStack cloud.

Goals

  • To quickly build dev OpenStack environments in a clean Ubuntu or Fedora environment
  • 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
  • To make it easy to prototype cross-project features
  • To provide an environment for the OpenStack CI testing on every commit to the projects

Read more at http://devstack.org.

IMPORTANT: Be sure to carefully read stack.sh and any other scripts you execute before you run them, as they install software and will alter your networking configuration. We strongly recommend that you run stack.sh in a clean and disposable vm when you are first getting started.

Versions

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 juno OpenStack cloud:

git checkout stable/juno
./stack.sh

You can also pick specific OpenStack project releases by setting the appropriate *_BRANCH variables in the localrc section of local.conf (look in stackrc for the default set). Usually just before a release there will be milestone-proposed branches that need to be tested::

GLANCE_REPO=git://git.openstack.org/openstack/glance.git
GLANCE_BRANCH=milestone-proposed

Start A Dev Cloud

Installing in a dedicated disposable VM is safer than installing on your dev machine! Plus you can pick one of the supported Linux distros for your VM. To start a dev cloud run the following NOT AS ROOT (see DevStack Execution Environment below for more on user accounts):

./stack.sh

When the script finishes executing, you should be able to access OpenStack endpoints, like so:

We also provide an environment file that you can use to interact with your cloud via CLI:

# source openrc file to load your environment with OpenStack CLI creds
. openrc
# list instances
nova list

If the EC2 API is your cup-o-tea, you can create credentials and use euca2ools:

# source eucarc to generate EC2 credentials and set up the environment
. eucarc
# list instances using ec2 api
euca-describe-instances

DevStack Execution Environment

DevStack runs rampant over the system it runs on, installing things and uninstalling other things. Running this on a system you care about is a recipe for disappointment, or worse. Alas, we're all in the virtualization business here, so run it in a VM. And take advantage of the snapshot capabilities of your hypervisor of choice to reduce testing cycle times. You might even save enough time to write one more feature before the next feature freeze...

stack.sh needs to have root access for a lot of tasks, but uses sudo for all of those tasks. However, it needs to be not-root for most of its work and for all of the OpenStack services. stack.sh specifically does not run if started as root.

This is a recent change (Oct 2013) from the previous behaviour of automatically creating a stack user. Automatically creating user accounts is not the right response to running as root, so that bit is now an explicit step using tools/create-stack-user.sh. Run that (as root!) or just check it out to see what DevStack's expectations are for the account it runs under. Many people simply use their usual login (the default 'ubuntu' login on a UEC image for example).

Customizing

You can override environment variables used in stack.sh by creating file name local.conf with a localrc section as shown below. 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.

[[local|localrc]]
VARIABLE=value

See the Local Configuration section below for more details.

Database Backend

Multiple database backends are available. The available databases are defined in the lib/databases directory. mysql is the default database, choose a different one by putting the following in the localrc section:

disable_service mysql
enable_service postgresql

mysql is the default database.

RPC Backend

Multiple RPC backends are available. Currently, this includes RabbitMQ (default), Qpid, and ZeroMQ. Your backend of choice may be selected via the localrc section.

Note that selecting more than one RPC backend will result in a failure.

Example (ZeroMQ):

ENABLED_SERVICES="$ENABLED_SERVICES,-rabbit,-qpid,zeromq"

Example (Qpid):

ENABLED_SERVICES="$ENABLED_SERVICES,-rabbit,-zeromq,qpid"

Apache Frontend

Apache web server can be enabled for wsgi services that support being deployed under HTTPD + mod_wsgi. By default, services that recommend running under HTTPD + mod_wsgi are deployed under Apache. To use an alternative deployment strategy (e.g. eventlet) for services that support an alternative to HTTPD + mod_wsgi set ENABLE_HTTPD_MOD_WSGI_SERVICES to False in your local.conf.

Each service that can be run under HTTPD + mod_wsgi also has an override toggle available that can be set in your local.conf.

Keystone is run under HTTPD + mod_wsgi by default.

Example (Keystone):

KEYSTONE_USE_MOD_WSGI="True"

Example (Swift):

SWIFT_USE_MOD_WSGI="True"

Swift

Swift is disabled by default. When enabled, it is configured with only one replica to avoid being IO/memory intensive on a small vm. When running with only one replica the account, container and object services will run directly in screen. The others services like replicator, updaters or auditor runs in background.

If you would like to enable Swift you can add this to your localrc section:

enable_service s-proxy s-object s-container s-account

If you want a minimal Swift install with only Swift and Keystone you can have this instead in your localrc section:

disable_all_services
enable_service key mysql s-proxy s-object s-container s-account

If you only want to do some testing of a real normal swift cluster with multiple replicas you can do so by customizing the variable SWIFT_REPLICAS in your localrc section (usually to 3).

Swift S3

If you are enabling swift3 in ENABLED_SERVICES DevStack will install the swift3 middleware emulation. Swift will be configured to act as a S3 endpoint for Keystone so effectively replacing the nova-objectstore.

Only Swift proxy server is launched in the screen session all other services are started in background and managed by swift-init tool.

Neutron

Basic Setup

In order to enable Neutron a single node setup, you'll need the following settings in your local.conf:

disable_service n-net
enable_service q-svc
enable_service q-agt
enable_service q-dhcp
enable_service q-l3
enable_service q-meta
enable_service q-metering
# Optional, to enable tempest configuration as part of DevStack
enable_service tempest

Then run stack.sh as normal.

DevStack supports setting specific Neutron configuration flags to the service, Open vSwitch plugin and LinuxBridge plugin configuration files. To make use of this feature, the settings can be added to local.conf. The old Q_XXX_EXTRA_XXX_OPTS variables are deprecated and will be removed in the near future. The local.conf headers for the replacements are:

  • Q_SRV_EXTRA_OPTS:

    post-config [linuxbridge] # or [ovs]

Example extra config in local.conf:

[[post-config|/$Q_PLUGIN_CONF_FILE]]
[agent]
tunnel_type=vxlan
vxlan_udp_port=8472

[[post-config|$NEUTRON_CONF]]
[DEFAULT]
tenant_network_type=vxlan

DevStack also supports configuring the Neutron ML2 plugin. The ML2 plugin can run with the OVS, LinuxBridge, or Hyper-V agents on compute hosts. This is a simple way to configure the ml2 plugin:

# 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).

Variable Name                    Notes
----------------------------------------------------------------------------
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.

Heat

Heat is enabled by default (see stackrc file). To disable it explicitly you'll need the following settings in your localrc section:

disable_service heat h-api h-api-cfn h-api-cw h-eng

Heat can also run in standalone mode, and be configured to orchestrate on an external OpenStack cloud. To launch only Heat in standalone mode you'll need the following settings in your localrc section:

disable_all_services
enable_service rabbit mysql heat h-api h-api-cfn h-api-cw h-eng
HEAT_STANDALONE=True
KEYSTONE_SERVICE_HOST=...
KEYSTONE_AUTH_HOST=...

Tempest

If tempest has been successfully configured, a basic set of smoke tests can be run as follows:

$ cd /opt/stack/tempest
$ tox -efull  tempest.scenario.test_network_basic_ops

By default tempest is downloaded and the config file is generated, but the tempest package is not installed in the system's global site-packages (the package install includes installing dependences). So tempest won't run outside of tox. If you would like to install it add the following to your localrc section:

INSTALL_TEMPEST=True

DevStack on Xenserver

If you would like to use Xenserver as the hypervisor, please refer to the instructions in ./tools/xen/README.md.

Additional Projects

DevStack has a hook mechanism to call out to a dispatch script at specific points in the execution of stack.sh, unstack.sh and clean.sh. This allows upper-layer projects, especially those that the lower layer projects have no dependency on, to be added to DevStack without modifying the core scripts. Tempest is built this way as an example of how to structure the dispatch script, see extras.d/80-tempest.sh. See extras.d/README.md for more information.

Multi-Node Setup

A more interesting setup involves running multiple compute nodes, with Neutron networks connecting VMs on different compute nodes. You should run at least one "controller node", which should have a stackrc that includes at least:

disable_service n-net
enable_service q-svc
enable_service q-agt
enable_service q-dhcp
enable_service q-l3
enable_service q-meta
enable_service neutron

You likely want to change your localrc section 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:

ENABLED_SERVICES=n-cpu,rabbit,g-api,neutron,q-agt
SERVICE_HOST=[IP of controller node]
MYSQL_HOST=$SERVICE_HOST
RABBIT_HOST=$SERVICE_HOST
Q_HOST=$SERVICE_HOST
MATCHMAKER_REDIS_HOST=$SERVICE_HOST

Multi-Region Setup

We want to setup two devstack (RegionOne and RegionTwo) with shared keystone (same users and services) and horizon. Keystone and Horizon will be located in RegionOne. Full spec is available at: https://wiki.openstack.org/wiki/Heat/Blueprints/Multi_Region_Support_for_Heat.

In RegionOne:

REGION_NAME=RegionOne

In RegionTwo:

disable_service horizon
KEYSTONE_SERVICE_HOST=<KEYSTONE_IP_ADDRESS_FROM_REGION_ONE>
KEYSTONE_AUTH_HOST=<KEYSTONE_IP_ADDRESS_FROM_REGION_ONE>
REGION_NAME=RegionTwo

Cells

Cells is a new scaling option with a full spec at: http://wiki.openstack.org/blueprint-nova-compute-cells.

To setup a cells environment add the following to your localrc section:

enable_service n-cell

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.

Local Configuration

Historically DevStack has used localrc to contain all local configuration and customizations. More and more of the configuration variables available for DevStack are passed-through to the individual project configuration files. The old mechanism for this required specific code for each file and did not scale well. This is handled now by a master local configuration file.

local.conf

The new config file local.conf is an extended-INI format that introduces a new meta-section header that provides some additional information such as a phase name and destination config filename:

[[ <phase> | <config-file-name> ]]

where <phase> is one of a set of phase names defined by stack.sh and <config-file-name> is the configuration filename. The filename is eval'ed in the stack.sh context so all environment variables are available and may be used. Using the project config file variables in the header is strongly suggested (see the NOVA_CONF example below). If the path of the config file does not exist it is skipped.

The defined phases are:

  • local - extracts localrc from local.conf before stackrc is sourced
  • post-config - runs after the layer 2 services are configured and before they are started
  • extra - runs after services are started and before any files in extra.d are executed
  • post-extra - runs after files in extra.d are executed

The file is processed strictly in sequence; meta-sections may be specified more than once but if any settings are duplicated the last to appear in the file will be used.

[[post-config|$NOVA_CONF]]
[DEFAULT]
use_syslog = True

[osapi_v3]
enabled = False

A specific meta-section local|localrc is used to provide a default localrc file (actually .localrc.auto). This allows all custom settings for DevStack to be contained in a single file. If localrc exists it will be used instead to preserve backward-compatibility.

[[local|localrc]]
FIXED_RANGE=10.254.1.0/24
ADMIN_PASSWORD=speciale
LOGFILE=$DEST/logs/stack.sh.log

Note that Q_PLUGIN_CONF_FILE is unique in that it is assumed to NOT start with a / (slash) character. A slash will need to be added:

[[post-config|/$Q_PLUGIN_CONF_FILE]]