Latest revision as of 00:00, 15 February 2013

[edit] Resin on Raspberry Pi

• Java On Raspberry Pi Performance
• Resin Changes To Support Raspberry Pi
• Paul's Raspberry Pi Journal
• sddd - Paul's improved dd for SD Card script for OSX

[edit] Resin on Raspberry Pi : Installation and Configuration

[edit] Preface

I'm going to assume you already have a working Raspberry Pi with Soft-float Raspbian Wheezy installed, updated, and accessible via SSH. If not, here are some links to help get you started:

• Soft-float Debian Wheezy Download
• Easy SD Card Setup on the Raspberry Pi Wiki
• sddd - Paul's improved dd for SD Card script for OSX
• Adafruit's First time configuration lesson
• raspi-config on the Raspberry Pi Wiki

I recommend you run "sudo apt-get update" and then "sudo apt-get upgrade". This will take something like 40 minutes, but it's good to have all the latest updates.

[edit] Java

• Java 6 and 7 do not support ARMv6 hardware floating-point calculations, so you must use the Soft-float version of Raspbian
• There is an early-access JDK 8 with hard-float support, but we have not tested Resin on JDK 8 yet
• Resin will run on both OpenJDK and Oracle JDK. I recommend Oracle JDK 7 for performance. See Java On Raspberry Pi Performance for the results of performance tests of Oracle JDK and OpenJDK on Raspberry Pi with Resin.
• To install OpenJDK 7, simply run "sudo apt-get install openjdk-7-jdk". java will install in your path using /etc/alternatives
• To install Oracle JDK download Java SE 7 JDK, Linux ARM v6/v7 Soft Float ABI from Oracle. There's nice step-by-step instructions at Savage Home Automation - Raspberry Pi - Installing Oracle Java Development Kit.

If you're getting this error when running java, "error while loading shared libraries: libjli.so: cannot open shared object file: No such file or directory", it means you're trying to run Java on hard-float Rasbian. Get the soft-float version.

[edit] Resin

• Download Resin 4.0.35 or later from www.caucho.com. 4.0.35 was the first version to include changes necessary to compile Resin's native libraries on a Raspberry Pi
• I'll install Resin Pro, but Resin Open-Source will fine also, but without the valuable features in the pro edition of course.
• Resin's native optimizations are always optional - it will run fine in pure Java mode with most features still available.

1. Download, unzip, and install Resin. There's nothing different here than any other Resin installation. Just make sure Java can be found. It must either be in the path or JAVA_HOME set as an environment variable.

wget http://www.caucho.com/download/resin-pro-4.0.35.zip
unzip resin-pro-4.0.35.zip
cd resin-pro-4.0.35
./configure

You should get a configuration summary that looks like this:

Resin Configuration Summary:

 RESIN       : 4.0.35
   home      : /usr/local/share/resin-4.0.35
   root      : /var/resin
   conf      : /etc/resin
   log       : /var/log/resin
   plugins   : common resin_os resin resinssl
   init      : /etc/init.d/resin

 JAVA_HOME   : /usr/java/bin/..

 JNI         : 32-bit
   include       : -I/usr/java/bin/../include -I/usr/java/bin/../include/linux
   CFLAGS        : 
   cflags_shlib  : -fPIC
   ld_shlib      : gcc
   ldflags_shlib : -shared -fPIC
   libs_shlib    : 
   epoll() for keepalives

 OPENSSL     : OpenSSL 1.0.1c 10 May 2012
   include   : /usr/include
   lib       : 
   libraries :  -lssl -lcrypto

2. Compile and install

make
make install

Resin will install to the standard directories /usr/local/share/resin, /var/resin, /etc/resin...

3. If you're on Resin Pro, now is the time to copy a license file to /etc/resin/licenses

cp /home/pi/10101.license /etc/resin/licenses/

4. Configure JVM Mode

Oracle JDK

There's 2 change required to run on Raspberry Pi and Oracle JDK:

4.1 Modify /etc/resin/resin.properties to change the jvm_mode parameter, as Java will NOT run on Raspberry Pi in server mode! Resin automatically uses -server unless this parameter is set:

vi /etc/resin/resin.properties

jvm_mode    : -client

4.2 Modify /etc/resin/cluster-default.xml, add a <watchdog-arg> parameter to set the Watchdog's JVM mode. Search for "jvm-mode" in the <server-default> section and put it after that. Example:

vi /etc/resin/cluster-default.xml

   ...
   <server-default>
     <jvm-arg-line>${jvm_args}</jvm-arg-line>
     <jvm-mode>${jvm_mode}</jvm-mode>

     <watchdog-arg>-client</watchdog-arg>
     ...

root@raspberrypi:/# resinctl start
Error occurred during initialization of VM
Server VM is only supported on ARMv7+ VFP

If you're seeing the message above, you need to modify resin.properties and cluster-default.xml as described above. Oracle JDK won't run in -server mode on a Raspberry Pi.

OpenJDK

4.1 On OpenJDK, you have a couple choices. -server implies -zero, the Zero-Assembler Project VM. There's also -jamvm, JamVM. Older version of OpenJDK had Cacao JVM, but that appears to have been removed in recent releases and replaced with Avain VM, although with -avian I get missing library errors... See [Java On Raspberry Pi Performance] for testing results we did on the different VMs.

5. Startup Resin!

root@raspberrypi:/# resinctl start
Resin/4.0.35 launching watchdog at 127.0.0.1:6600
Resin/4.0.35 started -server 'app-0' with watchdog at 127.0.0.1:6600

root@raspberrypi:/# ps -ef | grep java
root      8558     1 25 15:16 pts/0    00:00:31 /usr/jdk1.7.0_10/bin/java -client -Dresin.watchdog=app-0 -Djava.util.logging.manager=com.caucho.log.LogManagerImpl 
-Djavax.management.builder.initial=com.caucho.jmx.MBeanServerBuilderImpl -Djava.awt.headless=true -Dresin.home=/usr/local/share/resin- 4.0.35/ -Dresin.root=/var/resin 
-Xrs -Xss256k -Xmx32m com.caucho.boot.WatchdogManager -root-directory /var/resin -conf /etc/resin/resin.xml -log-directory /var/log/resin start --log-directory /var/log/resin
root      8609  8558 61 15:17 pts/0    00:00:57 /usr/jdk1.7.0_10/bin/java -Dresin.server=app-0 -Djava.util.logging.manager=com.caucho.log.LogManagerImpl 
-Djava.system.class.loader=com.caucho.loader.SystemClassLoader -Djava.endorsed.dirs=/usr/jdk1.7.0_10/jre/lib/endorsed:/usr/local/share/resin- 4.0.35//endorsed:/var/resin/endorsed 
-Djavax.management.builder.initial=com.caucho.jmx.MBeanServerBuilderImpl -Djava.awt.headless=true -Dresin.home=/usr/local/share/resin-4.0.35/ -Xss1m -Xmx256m 
-client com.caucho.server.resin.Resin --root-directory /var/resin -conf /etc/resin/resin.xml -server app-0  -socketwait 41515 -root-directory /var/resin -log-directory 
/var/log/resin start  --log-directory /var/log/resin
root      8674  1978  0 15:18 pts/0    00:00:00 grep java

[edit] Performance

At the moment, Resin performance on a Raspberry Pi is less than ideal, primarily attributed to disk access. Even using a class 10 SD Card, disk reads are slow, and disk writes are really slow. Resin does a lot of disk JAR file scanning and disk access to keep it's internal database synchronized (/var/resin/resin-data).

The worst performance hit is only during startup. Once Resin is up, it's mostly the disk access and compiling JSPs that is slow.

Performance tips:

1. Use Oracle JDK. It's significantly faster than Open JDK

2. Remove unnecessary .jar files.

3. Use pre-expanded .war directory. You may notice periods of blocking if you are using .war files, while Resin unzips and writes the files.

4. Use expand-preserve-fileset. This tells Resin to keep compiled JSPs between webapp changes.

<web-app-deploy path="webapps"
 expand-preserve-fileset="WEB-INF/work/**"/>

5. Be careful about your memory limits. Resin defaults to 256Mb heap size, plus 32Mb for the Watchdog. So if you have a 256Mb version Raspberry Pi, you could go over the limit. The newer Pi's are 512Mb. You definitely don't want to start swapping to disk, so it's a good idea to set -Xmx in /etc/resin/resin.properties:

jvm_args : -Xmx128M

[edit] Future Plans

The next version of Resin is currently in development, and with it we're planning a new resin-lite package. (This would be Resin 5, but we're calling it Resin 7 to match JEE7).

Resin Lite will be a stripped down, single .jar, non JEE compliant version of Resin. It will target running just servlets, JSP, (and probably PHP). There will be no persistent session or internal database, so the disk access delays should be greatly reduced.

I'm tracking the changes needed for it (Raspberry Pi specifically) at Resin Changes To Support Raspberry Pi. Feel free to contact us at presales@caucho.com for more information or with suggestions.