Sakai 10 install guide (binary)

1.0 Get the binary archive


(warning) Binary limitations. Post-release patches are not always packaged as jars, so a binary install forces a relatively static implementation that cannot be as readily patched later.

The binary distribution of Sakai provides a shortcut for those that already have Tomcat in place and configured as needed (including the database setup and configuration) and it does so by providing a pre-built Sakai that can simply be dropped into place. All you need to do is unpack the binary archive at the root Tomcat directory and the appropriate *.wars, *.jars, etc., for the Sakai application will be deposited in the correct locations.

The latest Sakai binary archive is available at http://source.sakaiproject.org/release/.


2.0 Verify/Install Java 1.7 


Oracle's Sun Java SE 7, a.k.a Java 1.7, is the preferred version to use with the Sakai CLE, because it has been tested the most thoroughly. Sakai 10 should have binary compatibility with Java 6. Certain files, such as *.jsp and *.jws, require compilation so downloading and attempting to use only the run time environment (JRE 7.0) will not suffice.  Mac OS X 10.7 and above does not include a Java installation by default. If you find Sun's version and naming conventions confusing, see Sun Java SE Naming and Versions for an outline of their practices.

(minus) Oracle's Sun Java SE 6 (a.k.a Java 1.6) has completed the EOL process and is no longer supported. If are still running Java 1.6 please note that security vulnerabilities exist in JDK/JRE 6.0.

Java 7

As of June 19, 2013, an issue has been reported with respect to Java 7 compatibility. The problem is in the Comparators and the workaround is to use the JVM property

-Djava.util.Arrays.useLegacyMergeSort=true

This issue has been fixed for jdk7u60+.

For details see - http://sakai-project-mail-list-archives.1343168.n2.nabble.com/Building-Sakai-Java-7-and-Sakai-comparators-tt7589944.html and SAK-38978 - Content Hosting comparators are incompatible with java 7 CLOSED

To confirm that Java is both installed on your system and is the correct version for Sakai, run java -version from the command line:

java -version

If Java is installed, basic version and build information will be displayed:

java version "1.7.0_03"
Java(TM) SE Runtime Environment (build 1.7.0_03-b05)
Java HotSpot(TM) 64-Bit Server VM (build 1.7.0_03-b05, mixed mode) 

If Java is not installed or you are running the wrong version you can download the Java SE 7.0 JDK release from Oracle's Sun archive:

http://www.oracle.com/technetwork/java/javase/archive-139210.html

Install the JDK, typically in the /opt directory, i.e. /opt/java. Install the JRE in a different directory (usually the default directory, especially if running Windows) or you may experience run-time issues.


2.1 Set Java environment variables


Several environment variables and related properties must be set for Java. For UNIX operating systems one typically modifies a startup file like ~/.bash_login to set and export shell variables while Mac users typically set and export environment variables in .bash_profile. For Windows, go to Start -> Control Panel -> System -> Advanced -> Environment Variables and set JAVA_HOME via the GUI.

Set the JAVA_HOME environment variable to point to the base directory of your Java installation and add Java's /bin directory to the PATH environment variable.

(info) If the variable JRE_HOME is already set or if you want to use a particular JRE if you have more than one JRE installed on your machine then you'll want to set the JRE_HOME variable as well. JRE_HOME is what Apache Tomcat uses when it starts up, but it defaults to use JAVA_HOME if JRE_HOME is not set. In most cases, setting JAVA_HOME should cover both cases sufficiently.

Variable

Unix

Mac

Windows

JAVA_HOME

export JAVA_HOME=/usr/java/java-current

export JAVA_HOME=/Library/Java/Home

JAVA_HOME=C:\jdk1.6.0_24

PATH

export PATH=$PATH:$JAVA_HOME/bin/

export PATH=$PATH:$JAVA_HOME/bin/

;C:\jdk1.6.0_24\bin

(warning) Windows: append the string to the end of the Path system variable

Set JAVA_OPTS

The default Java virtual machine (JVM) settings are insufficient for an application of Sakai's size. As a result several JVM parameters must be increased for Sakai to run, while others may need to be adjusted for optimal performance. At a minimum add the following property settings to your JAVA_OPTS environment variable.

(tick) We recommend that you define these settings in Tomcat's /bin directory in a file named setenv.sh (Unix/Mac) or setenv.bat (Windows). See the Tomcat section below for more details.

Unix/Mac:

export JAVA_OPTS='-server -Xms512m -Xmx1024m -XX:PermSize=128m -XX:MaxPermSize=512m -XX:NewSize=192m -XX:MaxNewSize=384m -Djava.awt.headless=true -Dhttp.agent=Sakai -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false -Dsun.lang.ClassLoader.allowArraySyntax=true'

Windows:

set JAVA_OPTS=-server -Xms512m -Xmx1024m -XX:PermSize=128m -XX:MaxPermSize=512m -XX:NewSize=192m -XX:MaxNewSize=384m -Djava.awt.headless=true -Dhttp.agent=Sakai -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false -Dsun.lang.ClassLoader.allowArraySyntax=true

(minus) Additional required settings

Certain JSF tools (chat, portfolios, test & quizzes) do not compile properly in Java 1.6. The workaround requires adding the system property allowArraySyntax in order to avoid deserialization bottlenecks in arrays (see SAK-17578 - Compiling with Java 1.6 breaks tools in Sakai CLOSED ). Second, Tomcat 5.5.27+ enforces strict quote escaping, a change in *.jsp handling that has yet to be addressed in certain tools such as portfolios (see SAK-15736 - NPE when trying to preview portfolios when running in tomcat 5.5.27 and websphere CLOSED ). Finally, specify an HTTP user agent other than "Java/xxxxx" in order to resolve Google and other RSS feeds (see SAK-10159 - Unable to interpret RSS from Google News CLOSED , SAK-13353 - Unable to render news from Times Higher Education Supplement (THES) CLOSED and SAK-18044 - Add -Dhttp.agent=Sakai to demo startup scripts to resolve Google RSS feed issues CLOSED ).

-Dsun.lang.ClassLoader.allowArraySyntax=true
-Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false
-Dhttp.agent=Sakai

Specify a Language and Locale (optional)

You can define the default language/locale when starting Sakai by setting the system properties -Duser.language and -Duser.region. For information on supported languages see the release notes or visit the i18N Work Group space.

-Duser.language=pt 
-Duser.region=PT

In the case your locale were not fully supported in Java (as it happens with Basque or Mongolian languages) you should read this information:
Endorsed I18n Project 

Specify an HTTP Proxy (optional)

In environments where local network policy or firewalls require use of an upstream HTTP proxy/cache, Sakai needs to be configured accordingly. Otherwise components or services which use HTTP requests, such as the BasicNewsService for RSS feeds in the News tool, cannot retrieve data from the target URLs. This can be fixed with the following JAVA_OPTS arguments:

-Dhttp.proxyHost=cache.some.domain 
-Dhttp.proxyPort=8080


3.0 Install Tomcat 7


  • Apache Tomcat - http://tomcat.apache.org/
  • Note: Always do a fresh install of Tomcat (please note that Tomcat has a bug. Please use Tomcat 7.0.65 or Tomcat 7.0.68, when released. Addendum 30January2017 - appears to work with 7.0.75 as of this writing. Is known not to work with 7.0.72 through 7.0.74 SAK-31912 - FacesContext already released in JSF tools with Tomcat 7.0.72+ RESOLVED )
  • Note: Windows users should ensure that there are no spaces in the complete tomcat path as this causes errors with JSF tools in Sakai
    GOOD: C:\opt\tomcat\, C:\sakaistuff\installs\tomcat\
    BAD: C:\program files\tomcat\, C:\opt\apache tomcat 7.0.1\
  1. Download Tomcat 7 if you're using Sakai 10- http://tomcat.apache.org/download-70.cgi
    Download Tomcat 8 if you're using Sakai 11 - https://tomcat.apache.org/download-80.cgi
    (The directions below are mostly the same for 7 or 8, but the setenv.sh is a little different)

    • Windows users should get the zip file instead of installing a service
      It makes viewing the tomcat logs easier and it is easier to configure

      If you're running the tag of Sakai 2.9.1 or earlier you need to be running Tomcat 7.0.21 or earlier. If you go any higher Webdav and Sitestats will have errors and not work. A better solution is to upgrade to the latest version of Sakai and Tomcat.
      SAK-28531 - Sitestats does not load with Tomcat 7.0.35 CLOSED
      SAK-23156 - IncompatibleClassChangeError from WebDAV LOCK operations giving 500 response code CLOSED
  2. Extract to /opt (symlink the apache-tomcat-7.0.x directory to tomcat after extracting)
    • Example (assuming you have saved the file as /opt/apache-tomcat-7.0.x.tar.gz)

      cd /opt
      tar xzvf apache-tomcat-7.0.x.tar.gz
      ln -nsf apache-tomcat-7.0.x tomcat
    • Windows users should just rename the directory since they cannot symlink
  3. Modify conf/server.xml for international character support
    1. Add URIEncoding="UTF-8" to the Connector element
      • <Connector port="8080" URIEncoding="UTF-8" ...
  4. Set environment variable: CATALINA_HOME=/opt/tomcat
  5. Add $CATALINA_HOME/bin to PATH
  6. Setup the SETENV file in the tomcat/bin directory with JAVA_OPTS (from Install Java 1.7+)

    Populate Database With Demo Data

    Instead of starting with an empty database you can add the flag -Dsakai.demo=true in addition to the others shown here. During your first Tomcat launch it will populate your database with test data (students, courses, etc). Once the data has been created remove this flag for subsequent Tomcat launches. Be advised that this flag will not trigger on a database with data already in it so you must make this choice during the initial setup. It should also be noted that without this flag one will not be able to create any course sites in Sakai unless Academic Term, Subject, Course, and Section data is manually added to the "cm_" tables in the database.


    1. Mac/Linux: Create a file called setenv.sh with the following (alternately, you can put this into your .bashrc file so they're automatically executed):

      Tomcat 7 Mac/Linux
      export JAVA_OPTS="-server -Xmx1028m -XX:MaxPermSize=320m -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false -Djava.awt.headless=true -Dcom.sun.management.jmxremote"
      Tomcat 8 Mac/Linux
      export JAVA_OPTS="-server -Xmx1028m -XX:MaxMetaspaceSize=512m -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false -Djava.awt.headless=true -Dcom.sun.management.jmxremote"
    2. Windows(PC): Create a file called setenv.bat with the following:

      Tomcat 7 Windows
      set JAVA_OPTS=-server -Xmx1028m -XX:MaxPermSize=320m  -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false -Djava.awt.headless=true -Dcom.sun.management.jmxremote
      Tomcat 8 Windows
      set JAVA_OPTS=-server -Xmx1028m -XX:MaxMetaspaceSize=512m -Dorg.apache.jasper.compiler.Parser.STRICT_QUOTE_ESCAPING=false -Djava.awt.headless=true -Dcom.sun.management.jmxremote
  7. [OPTIONAL] Delete the default webapps from the webapps dir

    rm -rf webapps/*
    

Configure tomcat 7/8 to use the old tomcat 5.5 classloader dirs, this is not needed for the master branch of Sakai and Sakai 11.

  1. Edit conf/catalina.properties
    1. Add the following to the line that begins with "common.loader=..."

      • Tomcat 7

        ,${catalina.base}/common/classes/,${catalina.base}/common/lib/*.jar
        
      • Tomcat 8

        ,"${catalina.base}/common/classes/","${catalina.base}/common/lib/*.jar"
        
    2. Add the following to the line that begins with "server.loader=..."

      ${catalina.base}/server/classes/,${catalina.base}/server/lib/*.jar
      
    3. Add the following to the line that begins with "shared.loader=..."

      ${catalina.base}/shared/classes/,${catalina.base}/shared/lib/*.jar
      
  2. Create the directories

    mkdir -p shared/classes shared/lib common/classes common/lib server/classes server/lib
    

Improve startup speed

You can improve startup speed under both Tomcat 7 and Tomcat 8 significantly.

Tomcat 7

Edit the file conf/catalina.properties and add the property to the bottom

org.apache.catalina.startup.ContextConfig.jarsToSkip=*.jar

Tomcat 8

Edit the file conf/context.xml and add this JarScanFilter block to the context

<Context>
    <JarScanner>
        <JarScanFilter defaultPluggabilityScan="false" />
    </JarScanner>
</Context>




4.0 Unpack the Sakai binary distribution


The Sakai binary archive is available at http://source.sakaiproject.org/release/. The URL redirects to the most current release. If looking for an earlier release append the version number to the URL (e.g., http://source.sakaiproject.org/release/2.9.3).

Download the archive into $CATALINA_HOME and then unpack the archive. Then start up Tomcat by running the Tomcat start up script in $CATALINA_HOME/bin. Unix/Mac users should make sure that they have write permissions to the Tomcat servlet container files and directories before proceeding or start up permission errors may occur.

(warning) If you wish to configure a binary installation you'll need to manually create a /sakai folder in $CATALINA_HOME to hold your sakai.properties file.


4.1 Configure Sakai


The sakai.properties file is a central configuration file that is typically stored in a /sakai subdirectory relative to the Tomcat home directory ($CATALINA_HOME). It is a non-XML text file containing a series of key/value pairs that is read using the load method of java.util.properties. Settings in sakai.properties govern everything from setting your institution's name to configuring your database. All settings in sakai.properties are read on startup; any changes you make subsequently will only take effect when you restart web application server. You may want to create a local.properties file in the same directory as sakai.properties. Properties listed in local.properties override sakai.properties. 

For a source installation the default default.sakai.properties file is located in the config module:

sakai-src/config/configuration/bundles/src/bundle/org/sakaiproject/config/bundle/default.sakai.properties

(warning) The bin package does not include a sakai.properties file. This is a deliberate exclusion; it eliminates the possibility of overwriting a local sakai.properties file if a bin package is opened over an existing Sakai installation.

If you need to override the default settings you must create your own sakai.properties file either from scratch or from a known working copy adding new key/value settings in order to customize your installation. We recommend that you review the default.sakai.properties file included in the source installation or in the appropriate maintenance branch.

The default location for your local sakai.properties file is $CATALINA_HOME/sakai. This folder is not created by Maven during the build and deployment process, so you will have to create it manually or via a script. You can also store Sakai's configuration files outside of your web application server's file hierarchy. For example, in a development environment you may find yourself frequently reinstalling Tomcat and unless you create a build script to automate the Tomcat installation and configuration process avoiding having to recreate $CATALINA_HOME/sakai and sakai.properties each time has its advantages.

To locate your properties file outside of your web application server environment modify the Java startup command or the JAVA_OPTS environment variable and set a system property named sakai.home. Make sure your external location is readable and writable by your web application server.

-Dsakai.home=/path/to/desired/sakai/home/


4.2 Default database support (HSQLDB)


By default Sakai 2.9 distributions (demo, binary, source) are configured to use an in-memory version of HSQLDB on start up. HSQLDB is deprecated for Sakai 10 and later.

Many developers and the vast majority of Sakai installations choose to run either MySQL or Oracle in their local and production environments and the default and sample sakai.properties include configuration settings for both databases. Click the "Configure" tab above for instructions on setting up Sakai to use MySQL or Oracle. For MySQL download https://mariadb.com/kb/en/mariadb/about-mariadb-connector-j/ and copy into the lib directory.

(info) You will not need to create Sakai database objects (tables, indices, etc) when setting up your database. Sakai generates its own database schema automatically during the Tomcat setup process via the autoDDL setting in sakai.properties.


4.3 Configure Database


Create a Sakai database with a default character set of UTF-8. Create a user account to which you will assign all permissions.

Use any database name and username you wish and then update your sakai.properties file (or even better, create a local.properties file, which has precedence).

In the example below the database is named "sakaidatabase" and the user account is "sakaiuser".

Excerpt from sakai.properties

username@javax.sql.BaseDataSource=sakaiuser
password@javax.sql.BaseDataSource=sakaipassword

## MySQL settings
# vendor@org.sakaiproject.db.api.SqlService=mysql
# driverClassName@javax.sql.BaseDataSource=com.mysql.jdbc.Driver
# hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
url@javax.sql.BaseDataSource=jdbc:mysql://127.0.0.1:3306/sakaidatabase?useUnicode=true&characterEncoding=UTF-8
# validationQuery@javax.sql.BaseDataSource=select 1 from DUAL
# defaultTransactionIsolationString@javax.sql.BaseDataSource=TRANSACTION_READ_COMMITTED


mysql -u root -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 272
Server version: 5.1.46 MySQL Community Server (GPL)

Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
This software comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to modify and redistribute it under the GPL v2 license

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> create database sakaidatabase default character set utf8;
Query OK, 1 row affected (0.00 sec)

mysql> grant all on sakaidatabase.* to sakaiuser@'localhost' identified by 'sakaipassword';
Query OK, 0 rows affected (0.00 sec

mysql> grant all on sakaidatabase.* to sakaiuser@'127.0.0.1' identified by 'sakaipassword';
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> quit


5.0 Start/Stop Tomcat


Start/stop Tomcat from the terminal by running the appropriate startup/shutdown script located in $CATALINA_HOME/bin:

Unix/Mac

sh startup.sh
sh shutdown.sh

Windows

startup.bat
shutdown.bat


6.0 Explore Sakai


You should at this point have a working Sakai installation. Now it's time to get started with adding users, creating work sites, and otherwise playing around with the tools. We won't try to present a full user's guide here, but we can offer some pointers to get you oriented and on your way, and link you to more exhaustive sources of information elsewhere.

The Gateway Page

Once Tomcat has started successfully, you should be able to direct your browser to its gateway page at http://localhost:8080/portal (or replace 'localhost' with the name of the server where it's installed). From the gateway page you can create new accounts or browse for public site content. You could start by creating a new account, but that can also be done as an admin, and since the admin functions are needed to allow this account the right permissions, it's just as well to start by logging in as the admin user. Sakai's out-of-the-box admin account is simply named 'admin' (with password also 'admin'), so use those credentials to log in.

My Workspace

Every user on the system - including the admin - has a private site called My Workspace. It's the landing point upon logging in, and it's the first site tab visible at the upper left. Running vertically along the left-hand side of the screen are links to the various different tool pages within a given site, and the admin's My Workspace has a different set of such options here than most (each different type of account can be configured to have a different set of tools in its My Workspace by altering a template - see below).

Other Sites

Each new (accessible) site becomes visible as a tab along the top, to the right of My Workspace. For most users, they initially only have access to one site - their My Workspace. The admin user is a little different, in that it has access to two. The second admin site (which you can enter by clicking on its tab) is entitled Administration Workspace which, strangely enough, looks exactly the same as the admin My Workspace. It is.

Why the redundancy? Because you'll likely want to make these admin tools available to a particular user who doesn't have access to the admin's My Workspace (no one has access to other people's My Workspace on the system). To allow anyone access to the admin tools, you need only add them to the list of users of the Administration Workspace, and then promote them in the site to the "admin" role.

Admin Tools

Creating Users

The first thing you may want to do is to change the admin password to something secure, and to start creating a few sample users on your system. You can do both of those tasks through the Users tool on the left. To change the admin user's password, simply click on the 'admin' username in the list of users, and edit the fields on the subsequent page. To create users, click on the New User action link at the top of the tool page.

Creating Sites

If you're itching to create your first worksite, you may be tempted to dive directly into the Sites tool. That would probably be a mistake. The Sites tool is a powerful way to construct an entire site from the ground up, with fine-grained control over its every page, tool, and configuration detail. But this flexible power comes with a price, making for an intimidating interface and epic-scale workflow. The Sites tool is therefore best used as a way to tweak an existing site after the fact, once the standard pieces have been more expediently assembled.

The best way to start creating sites, therefore, is to use the Worksite Setup tool. Click on the New link at the top of the tool page, and then, for simplicity's sake, choose the Project site type, which will allow you to avoid issues of academic term, etc., that are provoked by a "course" site - issues which are probably unnecessary if you just want to start playing with the tools. Either type of site will serve, however: both types of sites have all the tools available to them.

Step through the remaining site creation pages, making your preferred selections. Be sure to click the Create Site button at the end of the process. After doing so, you should see the site title visible as a new tab along the top of the screen.

Adding Users to Sites

Since you set this site up as an admin, the admin is technically the owner of this site, and its only member at first. If you want to add other sample users to this site in different roles, you can do so through the Site Info tool of the site itself.

Click on the tab of your new site (which should now be visible) to enter it, and then click on the Site Info link along the left hand side. Site Info has a number of site maintainer functions available as action links across the top, and Add Participants is the one that will allow you to connect other users to the site. These users will of course need to have been previously created.

As long as we're here in Site Info, it's worth pointing out that the Edit Tools link at the top will allow you to remove and add tools from the site.

Experimenting with Tools

You may have noticed an extra tool appear in your site - one which you didn't explicitly choose - labeled Help. This tool provides online documentation of the various bundle tools, and other facets of the system. This should be your companion as you learn more about the software's functionality.

This Help tool is also reached in a context-sensitive way by clicking on the question mark icons at the upper right of any particular tool frame. Clicking on those question marks will open up the precise content of the tool you happen to be in at the time.

At some later point, when you become comfortable with the standard tools, you may wish to see other, more experimental tools that are available for Sakai. The Sakai distribution includes provisional tools that are still maturing, but can already serve needs in innovative ways that the standard ones do not. These extra tools require additional steps to enable, so that system users will not stumble across them inadvertently if that's not desired, but you are encouraged to evaluate them for your own deployment.

Where to Learn More

About the Project

The sakaiproject.org site offers the best background and orientation to the project and its goals, but chances are you've already seen it. For more particular information on the progress and roadmaps of certain tools or other initiatives, see the relevant Confluence spaces.

Community Participation

The Sakai Community provide email forums on a variety of topics. The lists are open, however, they do reject all non-member email, so you need to join a list before you can post to it, though you can still access its archives.

The four main Sakai community lists are:

Announcements (announcements@apereo.org) - items of community-wide interest in Apereo, including Sakai (receive newsletters; learn about conferences and deadlines; follow general progress on upcoming releases; participate in calls for community input). A low-volume, read-only list, which everyone should join.

Building Sakai (sakai-dev@collab.sakaiproject.org) - designing, developing, testing, and documenting Sakai (learn about the technical details of building tools or integrating services; find guidelines for design and development of tools and services; locate technical specifications; learn about plans for future releases). For designers, programmers, developers, and quality assurance.

Pedagogy (pedagogy@collab.sakaiproject.org) - teaching and learning, collaboration, and other uses of Sakai (learn about best practices; share experiences; connect with user communities with similar interests, K-12, Higher-Ed, Portfolios). For teachers, staff, students, researchers, instructional designers, instructional technologists and end-user support staff.

Deploying Sakai (production@collab.sakaiproject.org) - implementing, installing, configuring, and supporting Sakai (find release documentation; learn about performance tuning; browse suggested hardware and software configurations; share examples of training, tutorial and support materials). For sysadmins, DBAs, and technical support staff.

There are also a variety of smaller, topic-specific working groups that use email lists, which you may also find of interest as you get more involved with the community.

To join a Sakai mailing list point your browser to:

http://collab.sakaiproject.org/mailman/listinfo/

and join the lists that interest you. You will be asked to fill out a short form (username, password) and you can select whether or not to receive each list post individually (default) or batched in a daily digest. Once you have submitted your request you will be sent a confirmation email with a short set of instructions for confirming your subscription request.

About Technical Matters

Reference materials for various technical issues are best found in Sakai's subversion repository (where these installation documents are also stored) or in the project's Confluence wiki. The docs in subversion can be found in the reference module, e.g. https://source.sakaiproject.org/svn/reference. See in particular the docs/architecture folder contained there, which contains a wide-ranging collection of technical white papers.

The Confluence wiki is a more informal source of information, but also valuable and broader in scope. New developers in particular should visit the Programmer's Cafe. You are encouraged to create an account there and participate.

But often the most incisive information comes from direct interaction with your peers. As mentioned above, the Collab Server is the place to go for this. For technical questions the best (and most active) such group is DG: Development, also commonly referred to by its alias, "sakai-dev."