Wednesday, 30 July 2014

Cross site replication with JBoss Data Grid



Are you afraid the Death Star or the Vogon Constructor Fleet are going to blow up your data on the Earth ? 
Navin Surtani has recorded a nice video demonstrating the use of JBoss Data Grid Cross-Site Replication and how it can be used to keep backups of your precious data off-site.

The code for the demo is also available. Enjoy.

Tuesday, 29 July 2014

Infinispan Security #3: HotRod authentication

Let's continue our excursus into the security features that are being developed within Infinispan 7.0 by having a look at how our high-performance cache remoting protocol HotRod was enhanced to support authentication.

Since Infinispan 5.3, HotRod has featured SSL/TLS support which, aside from encryption, also provides some form of authentication by optionally requiring client certificates. While this does indeed stop unauthorized clients from connecting to a remote cache, the level of access-control ends there. Now that we have full role-based authorization checks at the cache and container level, we want to be able to recognize users and map their roles accordingly.

As usual, we didn't want to reinvent the wheel, but leverage existing security frameworks and integrate them into our existing platform. For this reason, the protocol chosen to implement HotRod authentication is SASL, which is in widespread use in other connection-oriented transports (e.g. LDAP, Memached, etc).

Using SASL we can support the following authentication mechanisms out of the box (since they are part of the standard JDK/JRE):
  • PLAIN where credentials are exchanged in clear-text (insecure, but easieast to setup)
  • DIGEST-MD5 where credentials are hashed using server-provided nonces
  • GSSAPI where clients can use Kerberos tokens
  • EXTERNAL where the client-certificate identity of the underlying transport is used as the credentials
More SASL mechanisms can be plugged in by using the Java Cryptography Archictecture (JCA).

Since our preferred server distribution is based on a stripped-down WildFly server, we are essentially reusing the Security Realms of the container. This gives us the ability to validate users and to also retrieve group membership. against a number of sources (property files, LDAP, etc).

The following is an example server configuration which uses the ApplicationRealm to authenticate and authorize users. Since the <identity-role-mapper> is in use, role names will be mapped 1:1 from the realm into Infinispan roles.
The HotRod endpoint is using the SASL PLAIN mechanism. Note that two caches have been defined: the default cache, without authorization, and a secured cache, which instead requires authorization. This means that remote clients can access the default cache anonymously, but they will need to authenticate if they want to access the secured cache.
The following bit of code explains how to use the HotRod Java client to connect to the secured cache defined above:
All of the above is already available in Infinispan 7.0.0.Alpha5, so head on over to the download page to experience the goodness.

Monday, 28 July 2014

Upcoming Infinispan 7.0.0 Map/Reduce is blazing fast


Introduction


Our enthusiasm about Infinispan Map/Reduce implementation has been a driving impetus for new features and spectacular performance improvements we have achieved in the past months. As we approach the final Infinispan 7 release, we can not keep quiet about these improvements any longer, and we wanted to share the most significant new Map/Reduce features as well as a rather important performance improvement along with the details on how we achieved it.

New features


In the new features category, the most notable is a scalability improvement that allows storage of MapReduceTask's results in a distributed cache instead of returning results to the calling application. Infinispan now gives users the option to specify a target cache to store the results of an executed MapReduceTask. The results are available after the execute method (which is synchronous) completes. This new variant of the execute method prevents the master JVM node from exceeding its allowed maximum heap size.  Users could, for example, utilize the new execute method if objects that are the results of the reduce phase have a large memory footprint or if multiple MapReduceTasks are concurrently executing on the master task node. We have provided two variants of the new execute method:

We also enhanced parallel execution of map/reduce functions at each node and improved handling of intermediate results. Users can now specify custom intermediate cache to be used for a particular MapReduceTask.

Performance improvements


Infinispan 7 makes a rather big leap from a single threaded to a parallel execution model of both map and reduce phases on each Infinispan grid node. The final result of this change is on average fivefold faster execution of your typical MapReduceTask.

Even though map and reduce phases are sequential we can still execute the map and reduce phases themselves in parallel. If you recall, although Infinispan 6 executes map and reduce phases on all nodes in parallel, execution on each node itself is single-threaded. Similarly, reduce phase although executed on multiple nodes in parallel, each node executes its portion of reduction on a single thread.

Since we baselined Infinispan 7 on JDK 7, we decided to experiment with fork/join threading framework for parallel execution of both map and reduce phases [2]. If you recall fork/join framework enables high performance, parallel, fine-grained task execution in Java. Although parallel, recursively decomposable tasks are well suited for fork/join framework it may come as a surprise that parallel iteration of entries in arrays, maps and other collections represents a good fit as well. And do we have a well suited candidate for parallel fork/join iteration - cache's data container itself. In fact, most of the work is related to iterating entries from the data container and invoking map/combine and reduce function on those entries.

Map/combine phase is particularly interesting. Even if we use fork/join framework map and combine phases are distinct and until now - serially executed. Having serial execution of map and combine is not the only downside as map phase can be rather memory intensive. After all, it has to store all intermediate results into provided collectors. Combine phase takes produced intermediate values for a particular key and combines it into a single intermediate value. Therefore, it would very useful to periodically invoke combine on map produced keys/values thus limiting the total amount of memory used for map phase. So the question is how do we execute map/combine in parallel efficiently thus speeding up execution and at the same time limiting the memory used? We found the answer in producer/consumer threading paradigm.

In our case producers are fork/join threads that during map phase iterate key/value data container and invoke Mapper's map function. Map function transformation produces intermediate results stored into the Infinispan provided queue of collectors. Consumers are also fork/join threads that invoke combine function on key/value entries in those collectors. Note that this way map/combine phase execution itself becomes parallel and phases of mapping and combing are no longer serial. In the end, we have notably lowered memory usage and significantly improved overall speed execution of map/combine algorithm at the same time.

Performance lab results


Although initial performance results were more than promising, we were not satisfied. The throughput peaked for 32KB cache values but was much lower for larger and smaller values in our tests. We went back to the drawing board and devised the above described map/combine algorithm using fork/join framework and producer/consumer approach. This time the results from the performance lab were excellent. For more details on performance tests and hardware used please refer to [1].

As you can see on the graphs below we have improved performance for all cache value sizes. We were not able to significantly improve throughput for the largest 1MB and 2MB cache values. For all other cache value sizes we have seen on average five-fold throughput improvement. As throughput improvement is directly proportional to MapReduceTask speed of execution improvement, our users should expect their MapReduceTasks to execute, on average, five times faster in Infinispan 7 than in Infinispan 6.






[1] http://blog.infinispan.org/2014/06/mapreduce-performance-improvements.html
[2] We back ported relevant classes so users can still run Infinispan 7 on JVM 6

Thursday, 24 July 2014

Infinispan Security #2: Authorization Reloaded and Auditing

Since the last post on Infinispan Security, there have been a few changes related to how we handle authorization in Infinispan. All of these are available in the recently released 7.0.0.Alpha5.

Authorization Performance

Previously we mentioned the need to use a SecurityManager and javax.security.auth.Subject.doAs() in order to achieve authorization in embedded mode. Unfortunately those components have a severe performance impact. In particular, retrieving the current Subject from the AccessControlContext adds, on my test environment, 3.5µs per call. Since the execution of a Cache.put takes about 0.5µs when authorization is not in use, this means that every invocation is 8x slower.

For this reason we have introduced an alternative for those of you (hopefully the majority), that do not need to use a SecurityManager and can avoid the AccessControlContext: invoke your PrivilegedActions using the new org.infinispan.security.Security.doAs() method, which uses a ThreadLocal to store the current Subject. Using this new approach, the overhead per invocation falls to 0.5µs: a 7x improvement !
Security.doAs() is actually smart: if it detects that a SecurityManager is in use, it will fallback to retrieving the Subject via the AccessControlContext, so you don't need to decide what approach you will be using in production. The following chart shows the impact of using each approach when compared to running without authorization:


Auditing


An essential part of an authorization framework, is the ability to track WHO is doing WHAT (or is being prevented from doing it !). Infinispan now offers a pluggable audit framework which you can use to track the execution of cache/container operations. The default audit logger sends audit messages to your logging framework of choice (e.g. Log4J), but you can write your own to take any appropriate actions you deem appropriate for your security policies.

As usual, for more details, check out the Security chapter in the Infinispan documentation and the org.infinispan.security JavaDocs.

Thursday, 17 July 2014

Infinispan 7.0.0.Alpha5 relased!

Dear Community,

It is our pleasure to announce the Alpha5 release of Infinispan 7.0.0. This release includes numerous fixes and enhancements in every area of Infinispan. This will be our last alpha release as we move into beta stage and prepare for the final Infinispan 7.0 release.

Major theme of this release is Hot Rod eventing. Java Hot Rod clients can now subscribe to cache entry created, modified and removed events. For more details see  documentation. Infinispan Query is now based on Hibernate Search 5; we also use protoparser lib instead of relying on binary descriptors generated by protoc. Our JPA cache store works in Karaf; we have also made further Map/Reduce improvements and bug fixes. Starting with this release Infinispan server is based on WildFly 8.1 while Hot Rod SASL implementation supports QOP for encryption.

For a complete list of features and bug fixes included in this release please refer to the release notes. Visit our downloads section to find the latest release.

If you have any questions please check our forums, our mailing lists or ping us directly on IRC.

Cheers,
The Infinispan team.

Thursday, 5 June 2014

Map/Reduce Performance improvements between Infinispan 6 and 7


Introduction


There have been a number of recent Infinispan 7.0 Map/Reduce performance related improvements that we were eager to test in our performance lab and subsequently share with you. The results are more than promising. In the word count use case, Map/Reduce task execution speed and throughput improvement is between fourfold and sixfold in certain situations that were tested.

We have achieved these improvements by focusing on:
  • Optimized mapper/reducer parallel execution on all nodes
  • Improving the handling and processing of larger data sets
  • Reducing the amount of memory needed for execution of MapReduceTask

Performance Test Results


The performance tests were run using the following parameters:
  • An Infinispan 7.0.0-SNAPSHOT build created after the last commits from the list were committed to the Infinispan GIT repo on May 9th vs Infinispan 6.0.1.Final 
  • OpenJDK version 1.7.0_55 with 4GB of heap and the following JVM options:
    -Xmx4096M -Xms4096M -XX:+UseLargePages -XX:MaxPermSize=512m -XX:NewRatio=3 -XX:+UseConcMarkSweepGC -XX:+UseParNewGC
  • Random data filled 30% of the Java heap, and 100 random words were used to create the 8 kilobyte cache values. The cache keys were generated using key affinity, so that the generated data would be distributed evenly in the cache. These values were chosen, so that a comparison to Infinispan 6 could be made. Infinispan 7 can handle a final result map with a much larger set of keys than is possible in Infinispan 6. The actual amount of heap size that is used for data will be larger due to backup copies, since the cluster is running in distributed mode.
  • The MapReduceTask executes a word count against the cache values using mapper, reducer, combiner, and collator implementations. The collator returns the 10 most frequently occurring words in the cache data. The task used a distributed reduce phase and a shared intermediate cache. The MapReduceTask is executed 10 times against the data in the cache and the values are reported as an average of these durations.

    From 1 to 8 nodes using a fixed amount of data and 30% of the heap


    This test executes two word count executions on each cluster with an increasing number of nodes. The first execution uses an increasing amount of data equal to 30% of the total Java heap across the cluster (i.e. With one node, the data consumes 30% of 4 GB. With two nodes, the data consumes 30% of 8 GB, etc.), and the second execution uses a fixed amount of data, (1352 MB which is approximately 30% of 4 GB). Throughput is calculated by dividing the total amount of data processed by the Map/Reduce task by the duration. The following charts show the throughput as nodes are added to the cluster for these two scenarios:

    These charts clearly show the increase in throughput that were made in Infinispan 7. The throughput also seems to scale in an almost linear fashion for this word count scenario. With one node, Infinispan 7 processes the 30% of heap data in about 100 MB/sec, two nodes process almost 200 MB/sec, and 8 nodes process over 700 MB/sec.

    From 1 to 8 nodes using different heap size percentages


    This test executes the word count task using different percentages of heap size as nodes are added to the cluster. (5%, 10%, 15%, 20%, 25%, and 30%) Here are the throughput results for this test:

    Once again, these charts show an increase in throughput when performing the same word count task using Infinispan 7. The chart for Infinispan 7 shows more fluctuation in the throughput across the different percentages of heap size. The throughput plotted in the Infinispan 6 chart is more consistent.

    From 1 to 8 nodes using different value sizes


    This test executes the word count task using 30% of the heap size and different cache value sizes as nodes are added to the cluster. (1KB, 2KB, 4KB, 8KB, 16KB, 32KB, 64KB, 128KB, 256KB, 512KB, 1MB, and 2MB) Here are the throughput results for this test:

    These results are more interesting. The throughput in Infinispan 7 is higher for certain cache size values, but closer to Infinispan 6 or even slower for other cache size values. The throughput peaks for 32KB cache values, but can be much lower for larger and smaller values. Smaller values require more overhead, but for larger values this behavior is not expected. This result needs to be investigated more closely.

    Conclusion


    The performance tests show that Infinispan 7 Map/Reduce improvements have increased the throughput and execution speed four to sixfold in some use cases. The changes have also allowed Infinispan 7 to process data sets that include larger intermediate results and produce larger final result maps. There are still areas of the Map/Reduce algorithm that need to be improved:
    • The Map/Reduce algorithm should be self-tuning. The maxCollectorSize parameter controls the number of values that the collector holds in memory, and it is not trivial to determine the optimal value for a given scenario. The value is based on the size of the values in the cache and the size of the intermediate results. A user is likely to know the size of the cache values, but currently Infinispan does not report statistics about the intermediate results to the user. The Map/Reduce algorithm should analyze the environment at runtime and adjust the size of the collector dynamically.
    • The fact that the throughput results vary with different value sizes needs to be investigated more closely. This could be due to the fact that the maxCollectorSize value used for these tests is not ideal for all value sizes, but there might be other causes for this behaviour.

    Tuesday, 27 May 2014

    Iterate all the entries in the cache

    Dear all, with the release of 7.0.0.Alpha4 it was mentioned that we now support Distributed Entry Iterator which allows for iteration over all entries in the cache.  Iterating over all the entries in the cache has always been an highly demanded community feature. Existing methods (entrySet, keySet, size) were not a good fit because of potential OOM and were causing a lot of user annoyance. Voila a nice distributed solution :-)  ISPN-4222

    Public Interface Additions


    The added public API changes are as follows:


    AdvancedCache


    This returns an EntryIterable that can be used directly as an Iterable over the contents or also to pass a converter to convert the resulting value that is returned to another value or even type itself.


    EntryIterable



    EntryIterable also implements AutoCloseable and as such should be closed after iteration or if an exception case occurs.  Thus the Java 7 try with resources syntax should be used.

    Note that EntryIterable has a method that allows you to also provide an optional Converter to change the values to another type if desired. This conversion is done on the remote nodes and is preferable to be used when the values can be reduced in size to reduce overall payload size.

    An example of how to perform the iteration with any cache type.

    General Algorithm


    Essentially when the iterator is generated it will start an iteration process on the local node to retrieve all values local to that node (including from loader) and also a remote thread that will do the same thing on nodes one at at time. As values are retrieved they are made available to the iterator for processing. The chunkSize configuration for the State Transfer configuration will limit how many values are available to be waiting to be iterated on at a time (loader, local and remotely retrieved values count towards this). This is important to limit how many values are stored in memory when both using a loader and in distributed caches to help prevent an OOM condition from occurring.

    The provided KeyValueFilter is used on the various nodes to limit what entries are returned to the iterator and are sent to the remote node(s) when using a Distributed cache to limit how many results are returned. A converter is similar to the KeyValueFilter but it is ran on any entry that passes the filter to possibly converter the value to another such as a projection view if desired. Both the KeyValueFilter and Converter must be serializable for proper operation!

    The operation is also aware of rehash events occurring, since this could alter which node owns what entry. This is handled automatically by the iterator by tracking what segments have moved and requesting them from the other node if needed.

    Local, Replicated and Invalidation Cache Optimizations


    These caches have some additional optimizations from above in the following
    1. The KeyValueFilter and Converter do not need to be Serializable
    2. KeyValueFilter optimization is only relevant when using a loader
    3. Converter optimization is minimial, the main benefit being it allows code to be the same between cache types

    Gotchas


    This is just to talk about some various cases that users should be aware of.

    Transactional Behaviour

    When using the entry iterator in a transactional context, all of the values are retrieved outside of the current transaction if there is one, and no transaction is started if there isn't one.

    This is done due to the behaviour of Repeatable Read isolation level.  If not then then all of the retrieved values would have to be stored locally in the current context for that transaction, which would most likely cause an OOM condition in many cases.

    Removal using Iterator

    Since the iteration process does not take part of transactions, the remove operation of the iterator is not supported as well.  If desired the user should just invoke the remove method from the Cache itself to do this.

    Consistency Guarantees

    This iterator only guarantees consistency in regards to each value independently. That is it will show a view of each value that existed during the period of when the iteration began and when it completed. Thus it is entirely possible to see a subset of values if say a transaction was committed at the same time as iteration. This would require additional isolation level changes outside of the scope of the iterator to implement this, such as adding Serializable isolation level.

    Return type change

    Before ISPN 7 is released, it is still needed to change the return type from Map.Entry to instead be CacheEntry as users may need the Metadata stored with the entry as well. This will come in ISPN-4326

    Try it out


    Let us know if and how you guys plan on using this and any feedback would be appreciated!