A Couple Minutes With Some Toolkit Samples

Last night we released Beta 2 of the Terracotta 3.3 release. It has a number of improvements and updates to the Terracotta Toolkit including improved naming and factoring and additional clustered classes like AtomicLong and List. You can grab that or to get the absolute latest you can grab a nightly (my preference because the beta doesn't work with maven)

I pushed a couple of toolkit samples to GitHub (which by the way is awesome!). I didn't do hardly any cleanup or comments so just post questions to the blog if you need help.

http://github.com/sharrissf/Terracotta-Tools-and-Samples/

If your a Git user already I don't need to tell you how to check it out. If your not just hit "download source" on the upper right of the web page and don't worry about Git.

Four examples are included:

PlayingWithMapOfLocksExpress - A quick sample that show's how to create a clustered Map of Locks.

PlayingWithToolkitBarrier - Example of using a Cyclic barrier to coordinate between processes

PlayingWithToolkitClusterInfo - Example showing how to register a listener for cluster events.

PlayingWithToolkitQueue - Little sample on using a queue between two nodes

PlayingWithToolkitClusterCounter - Basic sample that show's using a clustered atomic long

You can run these from the command line by:

1. Downloading and unpacking the nightly build or beta from Terracotta
2. Staring the Terracotta server by calling the ./bin/start-tc-server.sh
3. Running 2 instances of the compiled versions of any of the above

java -cp target:INSTALL_DIR/common/terracotta-toolkit-1.0-runtime-ee-1.0.0-SNAPSHOT.jar PlayingWithToolkitClusterInfo

You can also run them using the Terracotta Maven Plugin:

mvn tc:run

To switch between the samples edit the pom.xml

A Couple Minutes With The Terracotta 3.3 Beta

With Terracotta platform version 3.3 our goal of creating an accessible application performance and scale-out solution is taking another big step forward. It's important to us that developers can find success using the ubiquitous Ehcache for performance, Hibernate for an ORM, Http Web Sessions for user state and Quartz for scheduling in a single node application. Then, without much thought or effort, add a couple lines of config to achieve scale-out and HA serving needs all the way through enterprise apps and into the cloud.

We have focused on a couple of high level areas in this release to take our solution to the next level.

• Simple Scale - Reduce the need for tuning and tweaking with an improved next gen datastore. It will allow the everyday user to achieve the kinds of scale needed for massive applications both in data size and number of nodes.

• Improved Visibility - We have added panels for Quartz and Sessions to our developer console giving full visibility to the full suite of performance and scale-out products. We have also added a more product focused organization of information in the tool.

• Simple HA - A new panel that makes it easier to monitor interesting events that occur in a cluster. Pre-built templates for various configurations. Simplified way of migrating nodes, better defaults.

• Modularity - We have exposed some of our most powerful pieces and parts as a versioned standard API that can be simply coded against to get things like, locking, queuing, maps and cluster topology. We use this API to build all four of our core products (Ehcache, Quartz, Hibernate 2nd level cache, Web Sessions).

While not everything made into the beta, enough is there to get a taste of where we are going. I encourage people to download it and try it as soon as possible. GA is just around the corner. Learn more on the release notes page.

Steve Jobs Stanford Commencement

Was reading a couple stories on the web this morning and I ran into two somewhat interesting lists over at Time Magazine. I kinda mocked the first one upon reading the title "Top 10 College Dropouts." I laughed and said to my Coworker and friend Orion, "Must be a slow news day!" Followed by spending the next 10 or 15 minutes dissecting the article. How many were either from or lived in California? how many dropped out of Harvard? Who the heck is Buckminster Fuller? "About 10 minutes in Orion rightly pointed out, "Article can't be too bad since you've spent the last 10 minutes talking about it." Of course he was right.

Followed that up by clicking a link taking me to the next list called "Top 10 Commencement Speeches." I know what your thinking now, "How much free time does this guy have?" I was enjoying a little candy after a hard working morning ;-). Anyway, I digress. I noticed that one of the names was on both lists. You guessed it, Steve Jobs, someone that anyone who has ever built anything of any kind should at least respect.

I set about to watch the commencement speech he gave in 2005. He basically tells 3 stories from his life experience. Much like Randy Pausch's last lecture their is a lot to be learned here. The first two stories are awesome and inspirational and many of us can relate to and learn from them. The third is also good/inspirational but a bit dark and kind of scary and depressing.

Anyway, since in this speech Steve talks so much about time, I will lead in with the opinion that listening to this commencement is time well spent. Check it out!

A Couple Minutes With Non-Stop Ehcache

Sometimes you just want to have an SLA (Service Level Agreement) when dealing with a component like a cache. You want to know that no matter what goes wrong, disk failures, deadlocks, network down, database locked up (for write-through) your threads won't be blocked for longer than your SLA. In the security world this is analogous to Layered Security where one is protected at multiple layers from breaches. In this case you are protected at multiple layers from hangs.

Non-Stop Ehcache

In comes NonStopCache. This is a decorator for Ehcache that allows one to specify an SLA. When using this decorator no operation is allowed to take longer than the SLA provided. All operations are isolated from the cache via a thread pool providing complete protection. The NonStopCache has multiple ways of configuring it. One can setup whether to serve stale data, perform noops or throw exceptions when SLA's are being violated covering most of the cases one needs.

Getting Started

Here's what I did to get started using clustered Ehcache and NonStopCache:

• Download Ehcache 2.1
• Download the NonStopCache 1.0
• Start the Terracotta server

ehcache-2.1.0-beta/terracotta/bin/start-tc-server.sh

• run the below program (source code below)

java -cp .:ehcache-core-2.1.0-beta.jar:slf4j-api-1.5.8.jar:slf4j-jdk14-1.5.8.jar:ehcache-terracotta-2.1.0-beta.jar:ehcache-nonstopcache-1.0.0-beta.jar MyFirstNonStopEhcacheSample

NOTE: Kill the Terracotta server when the printed output instructs you too.

Let's review the output:

Regular cache. No Decorator

The size of the cache is: 0

After put the size is: 1

Here are the keys:

Key:0

Done with cache.



Sleeping, Stop your server

Disconnected NonStop with noop cache.

The size of the cache is: 0

After put the size is: 0

Here are the keys:

Done with cache.



Disconnected NonStop with local reads cache.

The size of the cache is: 1

After put the size is: 1

Here are the keys:

Key:0

Done with cache.



Disconnected NonStop with exception cache.

Exception in thread "main" net.sf.ehcache.constructs.nonstop.NonStopCacheException: getKeys timed out

at net.sf.ehcache.constructs.nonstop.behavior.ExceptionOnTimeoutBehavior.getKeys(ExceptionOnTimeoutBehavior.java:114)

at net.sf.ehcache.constructs.nonstop.behavior.ClusterOfflineBehavior.getKeys(ClusterOfflineBehavior.java:120)

at net.sf.ehcache.constructs.nonstop.NonStopCache.getKeys(NonStopCache.java:264)

at MyFirstNonStopEhcacheSample.addToCacheAndPrint(MyFirstNonStopEhcacheSample.java:45)

at MyFirstNonStopEhcacheSample.(MyFirstNonStopEhcacheSample.java:40)

at MyFirstNonStopEhcacheSample.main(MyFirstNonStopEhcacheSample.java:60)

What Just Happened?



The cache is first loaded into an ordinary undecorated cache. This is performed before the server kill and proceeds without incident. The next round of operations on the cache were performed with the server down.

Since that cache is configured as noop all operations are ignored and the size of the cache appears as zero. This is great for when you just want to not bother with the caching if it isn't available.

Next round is local reads. This allows you to use the values that are available locally while the cache is unavailable. This is especially nice for read only or mostly read only caches that fit in memory and are always available.

After that we go to the exception version. If you have a cache of important coherent data but you don't want threads blocked this setting is for you. It will blow cache operations out of the thread so your container can just keep going by either showing an error page or getting the data from elsewhere.

Some interesting points here:

• These decorators are all being used on the same cache. This way you can make the behavior specific to the user of the cache. It gives tremendous flexibility.
• You'll notice this little sample flies through despite the timeout being set to 13 seconds. This is because it's in fail fast mode. In this configurable mode if the cache knows it can't communicate it will return the failure case immediately. If that's not what you want you can instead set it up to not fail fast and wait the full timeout no matter what.
• I did this work in config but the same setup can be done in code

The Code

MyFirstNonStopEhcacheSample.java







And the Config file ehcachenonstop.xml:

A Couple Minutes With Terracotta Toolkit Nightly

A couple days ago I wrote a short blog about our goal of creating a Terracotta Toolkit for others to easily build simple to use scaled out frameworks, tools and in some cases apps. This same exact toolkit is used to build Ehcache, Hibernate, Http Sessions and Quartz with Scale and HA just by adding 2 lines of config. I was pretty shocked and excited about what a tremendous reaction this blog and the toolkit received. Usually when I write a blog most of it's traffic comes from awesome sites like DZone but this blog was different. I actually got considerably more direct traffic from things like e-mails and twitter than anything conventional. That kind of viral excitement shows a much deeper level of curiosity and is tremendously motivating for the team here. Anyway, I digress.

Me being the curious type I decided to do something a little dangerous yesterday. I asked Geert, one of the leads on the Terracotta toolkit project, if we were in a state where I could play around with it a bit and get a sense of how hard it is to get started. We discussed the usual caveats, "We haven't agreed on some of the naming and factoring stuff yet?" which I clearly understood. Knowing that fact and that I'd be working off a nightly(this link downloads it) I set out to follow his simple instructions and see just how easy it was. Here is what I did.

Geert gave me a simple cyclic barrier sample to work off of. This is a sample I've whipped up my self a few times over the years. Many of our earliest users leveraged Terracotta strictly as a distributed lock manager and that's what this simple sample does as well. You start the app with a barrier name and a node count and it just hangs until the node count is reached. Seems like as good of a sample as any to highlight how to get started with the toolkit.

• Downloaded the nightly and unpacked

tar -xzvf terracotta-trunk-nightly-rev15534.tar.gz

• Grabbed a quick sample app

import org.terracotta.api.ClusteringToolkit;

import org.terracotta.api.TerracottaClient;

import org.terracotta.coordination.Barrier;

public class PlayingWithExpressBarrier {

public static void main(String[] args) {

final String barrierName = args[0];

final int numberOfParties = Integer.parseInt(args[1]);

//Start the Terracotta client

ClusteringToolkit clustering = new TerracottaClient(

"localhost:9510").getToolkit();

//Get an instance of a barrier by name

Barrier barrier = clustering.getBarrier(barrierName,

numberOfParties);

try {

System.out.println("Waiting ...");

int index = barrier.await();

System.out.println("... finished " + index);

} catch (Exception e) {

e.printStackTrace();

}

}

}

• I worked in eclipse so at this point all I had to do is add the toolkit jar to the classpath to get it to compile

terracotta-trunk-nightly-rev15534/common/terracotta-toolkit-1.0-runtime-1.0.0-SNAPSHOT.jar

• Now kickoff the Terracotta server

terracotta-trunk-nightly-rev15534/bin/start-tc-server.sh

• And run the sample 3 time

java -cp .:terracotta-toolkit-1.0-runtime-1.0.0-SNAPSHOT.jar barrierName 3

The first two nodes should hang waiting for the 3rd node. Once the 3rd node is started all three should run to completion. This is just a little taste of what is coming.

The toolkit will have highly concurrent maps, locks, counters, queues, evictors and more so stay tuned. All of the toolkit classes will have tests in our TCK. The toolkit will run on any 1.5/1.6 JVM and requires no boot-jars, agents or container specific code. Given versions of the TCK will allow people to just drop in that toolkit jar at runtime for any app developed using that version of the API provided by the version of the TCK. I'll talk a bit more about how versioning the toolkit API will work in a future blog but it will work like any other spec. You can use any implementation that implements the spec. Enjoy, much more to come.

Countdown To The Terracotta Toolkit Beta

Countdown To The Terracotta Toolkit Beta

Over the last year, Terracotta has launched four great products backed by the snap-in HA and scalability of the Terracotta Server Array: Enterprise Ehcache, BigMemory for Enterprise Ehcache, Web Sessions and Quartz Scheduler. Building these products has left us feeling a bit greedy. In order to free ourselves from this guilt we've created a toolkit that has allowed us to rapidly build these easy-to-use, high-scale/HA products.

The Revolution Begins

So why should we be the only ones who have all the fun. Lots of smart people out there can build clustered caches, frameworks, and tools? So we are creating the Terracotta toolkit and adjacent Terracotta Compatibility Kit. We will be releasing a set of standard parts like highly concurrent distributed maps, clustered evictors, queues, locks, counters, cluster events etc that can be used by anyone so that they might realize their vision of what the developers of the world should use. This kit was built with a few core goals in mind:

• Ease of use is paramount - For both the developers that leverage the Terracotta toolkit and the people who use the stuff built using the Terracotta toolkit
• Stable API matters - We are building a compatibility kit and will maintain a strict and clear versioning scheme so that framework developers can rely on and clearly know what versions of Terracotta can work with the API version used in the application. Your users can just drop in any version of the terracotta-toolkit.jar that implements the version of the API you coded against.
• Parts is Parts - Get all the useful parts we use to build our products packaged and out for others to use.
• Scale Continuum - The parts should work both clustered and unclustered continuing our vision of a scale continuum.

The beta of this toolkit is a few short weeks away and we can't wait to see what great stuff people will build on it. Come show us how a cache should be built, come show us what tools we haven't even thought of.

With this toolkit pretty much any framework developer will be able to build out their HA, distributed and scale out dreams.

Dave Klein's Scale Grails Webinar

As someone who spent years in the Smalltalk world I have a special place in my heart for powerful/flexible frameworks and languages that strive for simplicity for the developer. Grails is one of the most powerful and flexible frameworks around and modern representation of those Smalltak values. Some would argue that it's only major missing features are scale-out and HA. The great news on that front is that Grails is built on Quartz, Ehcache, Http Sessions and Hibernate all of which can be scaled with Terracotta in a couple lines of config each. By scaling these four frameworks you can completely scale Grails.

Check out this webinar from the guy who wrote the book on Grails Dave Klein and and learn about it for yourself: