Casual mass parallel computing
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Casual mass parallel computing



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Casual mass parallel computing Casual mass parallel computing Presentation Transcript

  • Casual mass parallel data processing in Java Alexey Ragozin Mar 2014
  • Building new bicycle …
  • Build Vs. Buy Build • No dedicated team to support infrastructure • Very specific tasks • Exclusive use of infrastructure • Reasonable scale Buy • Product can bought as service (internal or external) • Large scale • Multi tenancy • You are going to use advanced features (e.g. map/reduce)
  • “Casual” computing • Small computation farms (< 100 servers) • Team owns both application and grid • Java platform • Reasonably short batches (< 24 hours) • Reasonably small data sets (< 10 TiB)
  • Simple master slave topology Master process Task queue Slave Slave Slave Scheduler AdvertiseTask Report
  • Simple master slave topology Control plane  RMI Queue / scheduler  Simple in memory queue  May be more complex than just task queue Data plane …
  • Data plane Never, ever, try to send data over RMI  File system  Avoid network mounts! In-memory key-value  Client side sharding works best Disk database (RDBMS or NoSQL)  Consider prefetch of data Direct socket streaming …
  • Distributed objects revised Pit falls of CORBA/RMI • IDL – functional contract • IDL – protocol Separating concerns • Functional contract – wrapper object • Protocol – hidden remote interface
  • Distributed objects revised Renewed distributed objects paradigm Strong • Polymorphism • Encapsulation  Network protocol, caching aspects etc Weak • Homogenous code base required • Synchronous network communications
  • Brute force  Build / package  Deploy / SCP  Restart slaves  Start batch  Change code, repeat Deployment problem Computation grid software  Compile and run batch Behind scene  Your classes would be collected  Associated with batch  Deployed on participating slaves
  • Central scheduler topology Batch controller Slave Slave Slave Pull task Task Report Queue server Task queue Batch controller Add tasks Consume reports
  • Or more elaborated
  • Flow organized tasks • Input data available before task starts • e.g. Map/Reduce Collaborative tasks • Tasks communicate intermediate results to each other • e.g. physic simulations Flavors of parallel processing
  • Get back to data plane Rules of thumb • Insert / delete – never update • Write locally (reducing risks) • Read remotely (retry on error) • Store input as is  File system  Document / column oriented NoSQL • Input and temporary data is different  Choose right store for each
  • Exploiting file system Avoid network file systems • File system concept is not designed to be distributed • Good network file system cannot not exists • Use simple remote file access protocols • SCP (unencrypteddatatransferoptionsaddedbyCERNguys) • HTTP (ifyoureallydonotwantSCP) Cheap SAN could be build from open source
  • Algorithmic optimization Parallel computing • N times speed up will increase your OPEX and CAPEX cost by N*lg(N) Algorithmic optimization • Up front costs only • Orders of magnitude optimization opportunities • Exciting coding • Ecological way of computing 
  • Streaming algorithms Finding N most frequent elements • Min-Count Estimating number of unique values • HyperLogLog Distribution histograms
  • NanoCloud – drastically simplified coding for computing clusters
  • @Test public void hello_remote_world() { Cloud cloud = CloudFactory.createSimpleSshCloud(); cloud.node("").exec(new Callable<Void>(){ @Override public Void call() throws Exception { String localhost = InetAddress.getLocalHost().toString(); System.out.println("Hi! I'm running on " + localhost); return null; } }); } As easy as …
  • All you need is … NanoCloud requirements  SSHd  Java (1.6 and above) present  Works though NAT and firewalls  Works on Amazon EC2  Works everywhere where SSH works
  • Master – slave communications Master process Slave hostSSH (Single TCP) Slave Slave RMI (TCP) std err std out std in diag Slave controller Slave controller multiplexed slave streams Agent
  • Links NanoCloud • • Maven Central: org.gridkit.lab:telecontrol-ssh:0.7.23 • ANT task •
  • Thank you Alexey Ragozin - my articles - my open source code - community events in Moscow