BuildBot Configuration

This document attempts to discuss configuration details of the BuildBot system for OSGeo projects.

= Operational Configurations =

List of configured and running instances of BuildBot is available at OSGeo BuildBot website: http://buildbot.osgeo.org

= About BuildBot =

The BuildBot is a system to automate the build and test cycle during a software development process.

BuildBot homepage: http://buildbot.net/

Thanks to Howard Butler's installation of BuildBot, we've been able to test it with some of Open Source GIS projects for a few months.

After these tests, we've found that:


 * BuildBot works very well
 * BuildBot has a very positive effect on the development of the projects
 * BuildBot an important communication channel about compilation and testing issues
 * BuildBot helps developers and users to observe a cycle of development in details
 * BuildBot decreases time needed to compile and test changes in a multiplatform environment

The main objective of this initiative is to install and configure BuildBot instances for the OSGeo projects.

= BuildBot Administration =

The prototype infrastructure configuration and testing started by:


 * Mateusz Loskot
 * Ari Jolma
 * Howard Butler
 * Frank Warmerdam
 * Tamas Szekeres

(add info about administration policies, tasks responsibility, for the OSGeo BuildBot)

= BuildBot Configuration =

Following section describes details of BuildBot infrastructure configuration hosted on one of the OSGeo servers.

Current installation of BuildBot is based on versions:

[buildbot@xblade14 ~]$ buildbot --version Buildbot version: 0.7.10p1 Twisted version: 8.1.0

Configuration Files
All files of BuildBot configuration are maintained in OSGeo SVN repository (see Ticket #102) in dedicated module:

https://svn.osgeo.org/osgeo/buildbot/

which is accessible by dedicated SVN user buildbot.

It means, that $HOME directory of buildbot user is under revision control, being a working copy of the buildbot module in SVN repository.

None of versioned files do NOT contain any sensitive data like BuildBot slave passwords. Passwords are being kept out of the versioned tree, dedicated etc directory, stored in Python script files (.py) in form of regular Python dictionaries. These files are then imported as Python modules where necessary:

import passwd_gdal as secret

The location of password files is added to PYTHONPATH.

All directories and files that should not be stored in the SVN repository have been added to svn:ignore property. There are no binary files maintained in the repository.

Maintenance
Every time changes are applied to configuration files, they must be submitted to back to the repository with appropriate log message, for instance:

svn ci -m "buildbot: Added new build step to GDAL slave on telascience." --username buildbot

Please remember, that commit must be issued as SVN user buildbot, but not as any other OSGeo SVN user.

Server
The OSGeo BuildBot Master is hosted on one of the Telascience Blades:


 * Hostname: xblade14-2
 * IP:      198.202.74.219

(add / link to details about installed development software and versions)

Telascience xblade11-2 (198.202.74.216) is allocated for buildbot slaves. Some slaves are also setup on xblade14-2 though we are avoiding adding more there if possible.

Basic concepts
The BuildBot system architecture is based on two base concepts:


 * buildmaster - the brain, controls single instance of BuildBot
 * buildslave - the worker controlled by the buildmaster, performs all steps defined for a build

Selected server hosts all instances of the OSGeo BuildBot infrastructure.

A single instance of BuildBot, running on the OSGeo server, consists of single buildmaster and single buildslave.

Development team of particular project is able to connect more buildslaves running on separate machines, remotely. Buildslaves are connected to the buildmaster in a star topology. They connect to the buildmaster over a TCP connection to a publically-visible port (See Buildmaster ports section).

Every project gets its own instance of the OSGeo BuildBot and can connect various external buildslaves.

(add picture showing visualizing the structure of the OSGeo BuildBot infrastructure

BuildBot user

 * BuildBot runs as user (also see User Security section)

buildbot


 * Home directory for buildbot user points to:

/osgeo/buildbot

which is also linked to /home/buildbot.

User security
buildbot is a normal Linux user with LDAP account.

The access is secured with password.

If you need access to buildbot user privileges, please contact OSGeo BuildBot administrators.

OSGEOBUILDHOME
All BuildBot instances live in common home directory:

/osgeo/buildbot


 * buildbot user references to BuildBot instances using OSGEOBUILDHOME variable:

OSGEOBUILDHOME=/home/buildbot


 * BuildBot software (Python module) has been installed to:

PYTHONPATH=$OSGEOBUILDHOME/usr/lib/python2.4/site-packages

See BuildBot directories section for details about OSGEOBUILDHOME environment variable.

BuildBot directories
Following subsection explains directories layout used by the OSGeo BuildBot infrastructure.


 * BuildBot infrastructure base directory (later referenced as OSGEOBUILDHOME):

/osgeo/buildbot


 * BuildBot software (Python 2.4 packages) installation prefix:

/osgeo/buildbot/usr

BuildBot web page
(configure HTTP servers and DNS for the BuildBot on the OSGeo servers)

The main URL of the OSGeo BuildBot is

http://buildbot.osgeo.org

It's dedicated to:


 * list existing BuildBot instances used by OSGeo projects
 * list URLs to BuildBot status pages

NOTE: The BuildBot web page is not yet accessible. Subdomain has not been set up yet, etc.

BuildBot instance per project

 * Base directory for BuildBot instance for one project:

$OSGEOBUILDHOME/

where   is a placeholder for lower-case name of a project.

This path represents directory for single instance of the OSGeo BuildBot used by particular project.

Next, inside a project BuildBot instance directory, we have:


 * buildmaster

$OSGEOBUILDHOME/ /buildmaster


 * buildslave

$OSGEOBUILDHOME/ /buildslave


 * The BuildBot status page for particular project can be accessed through:

http://buildbot.osgeo.org/ /

or using address schema as URL:PORT:

http://buildbot.osgeo.org:PORT

NOTE: See note about inaccessibility of the BuildBot web page.

GDAL BuildBot example
The OSGeo BuildBot instance for GDAL project (let's call it GDAL BuildBot) is hosted inside the:

$OSGEOBUILDHOME/gdal

what expands to following path:

/osgeo/buildbot/gdal

The GDAL BuildBot uses single instance the buildmaster:

$OSGEOBUILDHOME/gdal/buildmaster

and single instance of the buildslave, local one:

$OSGEOBUILDHOME/gdal/buildslave

Next, GDAL developers can connect remote buildslaves hosted on various platforms, for exmaple on Mac OS. All buildslaves (one local and N number of remote slaves) are controlled by the GDAL BuildBot buildmaster.

The GDAL BuildBot status page URL is:

http://buildbot.osgeo.org/gdal/

or

http://buildbot.osgeo.org:8500

Buildmaster ports
This section explains details of TCP connection ports configuration for buildmaster instances.

Buildmaster of every OSGeo BuildBot instance is configured using two TCP ports:


 * one, to listen on for connections from buildslaves - SLAVEPORT
 * second, used by internal web server to listen on for connection from Web clients requesting for the BUildBot status web page - HTTPPORT

The OSGeo BuildBot infrastructure uses following scheme to assign BuildBot instances with TCP ports:


 * Port number XXYY, where
 * XX identifies port category: SLAVEPORT uses 15 (15YY) and HTTPPORT uses 85 (85YY)
 * YY identifies particular instance of the OSGeo BuildBot, a project


 * SLAVEPORT ports start from 1500 and HTTPPORT ports start from 8500


 * Both ports, SLAVEPORT and HTTPPORT, incement simultaneously, for example:

project A uses 1501 and 8501, where 01 is the instance (project) identifier

project B uses 1527 and 8527, where 27 is the instance (project) identifier


 * According to this scheme, there is a room for 100 instances of the OSGeo BuildBot (shortly, 100 OSGeo projects).

= BuildBot Startup =

On xblade14-2 machine, all Buildbot instances are configured to start on boot. This dedicated entry in crontab for buildbot user on xblade14-2:

$ crontab -l OSGEOBUILDHOME=/osgeo/buildbot @reboot $OSGEOBUILDHOME/buildbot_clean_logs.sh
 * 1) On Boot, clean Buildbot logs and start all instances

= BuildBot Maintenance =

Start Buildbot Instance Manually
$ cd $OSGEOBUILDHOME $ ./buildbot_start.sh 

where  is name (absolute or relative path) of a Buildbot instance directory. For example, command to start GDAL Buildbot is:

$ ./buildbot_start.sh gdal

Stop Buildbot Instance Manually
$ cd $OSGEOBUILDHOME $ ./buildbot_stop.sh 

where  is name (absolute or relative path) of a Buildbot instance directory. For example, command to stop PROJ.4 Buildbot is:

$ ./buildbot_stop.sh proj.4

Restart Buildbot Instance Manually
$ cd $OSGEOBUILDHOME $ ./buildbot_restart.sh 

It's also possible to restart all instances at once:

$ login to buildbot.osgeo.org. $ sudo su buildbot $ cd /osgeo/buildbot $ ./restartall.sh

Often after an unclear reboot, it is necessary to clean the old daemon pid files before a start/restart will work properly.

$ cd /osgeo/buildbot $ rm */*/twistd.pid

Logs Cleanup
Sometimes, logs and generated files take a lot of disk space. There is a script dedicated to do cleanup for all configured and active Buildbot instances on the xblade14-2 machine. In order clean all logs of all Buildbot instances, run following script as buildbot user: $ cd $OSGEOBUILDHOME $ ./buildbot_clean_logs.sh

= Additional features proposal =


 * Builds status delivery on e-mail or IRC channel
 * Automatic monitoring of source changes, so builds can be automatically triggered by commits

= OSGeo BuildBot Documentation =


 * All activated OSGeo BuildBot instances are listed here http://buildbot.osgeo.org/

HOWTO
(some documents need to be written)


 * How to create new OSGeo BuildBot instance
 * How to connect new buildslave to an existing buildmaster
 * How to configure URL redirects for status page of new BuildBot instance

= References =

List of articles related to / depending on the OSGeo BuildBot installation and configuration project:


 * System Administration Committee
 * SAC TODO List
 * SAC Service Status
 * Automated Build/Smoke Test System in the Project Infrastructure Migration