Deployment

Deployment

Introduction

If using sbt run to launch the job is not acceptable, it's possible to make self-contained fat-jars for deployment with:

Sbt-assembly

First check sbt-assembly for up to date information and documentation. This should be your first reference point. However, the way we have found works best /and please let us know if you find a better way/ is:

First add sbt-assembly plugin, at project/plugins.sbt with

addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.10.2")

And now at the top of your build.sbt add the required incantation:

import AssemblyKeys._

assemblySettings

Quick Hack

Ben Wing's suggestion provides a quick and easy solution by using a merge strategy, by putting this at the bottom of your build.sbt:

mergeStrategy in assembly <<= (mergeStrategy in assembly) { mergeStrategy => {
 case entry => {
   val strategy = mergeStrategy(entry)
   if (strategy == MergeStrategy.deduplicate) MergeStrategy.first
   else strategy
 }
}}

The downside is, that this brings in dependencies that are not strictly required (Avro, Hadoop, etc...).

The big advantage to this approach, is that sbt run still works

Ugly Hack

We can also fake the libraryDependencies to build a proper jar. Please note, the way we change this, will make it incompatible with a normal sbt run. So you might want to have two versions of your build.sbt

First of all, we want to only get some of Scoobi's dependencies (namely we don't want Hadoop itself, likely don't need Avro, and anything else that would trick up sbt-assembly). So what can use is a little trick:

"com.nicta" %% "scoobi" % "0.9.2" intransitive()

However, we do need some of Scoobi's dependencies -- so we have to add them in manually. Check out Scoobi's build.sbt (and the correct branch/revision) for the canonical list, but for example it might be:

"org.scala-lang"                    %  "scala-compiler"            % "2.10.3",
"org.apache.avro"                   %  "avro"                      % "1.7.4",       // Note: you only need this if you use it
"com.thoughtworks.xstream"          %  "xstream"                   % "1.4.4"        intransitive(),
"javassist"                         %  "javassist"                 % "3.12.1.GA",
"com.googlecode.kiama"              %% "kiama"                     % "1.6.0",
"com.chuusai"                       %  "shapeless_2.10.2"          % "2.0.0-M1",

And lastly, we probably want sbt compile to work -- so we add in all the dependencies we excluded, but as a provided". e.g.

"org.apache.hadoop" % "hadoop-common"                     % "2.2.0" % "provided",
"org.apache.hadoop" % "hadoop-hdfs"                       % "2.2.0" % "provided",
"org.apache.hadoop" % "hadoop-mapreduce-client-app"       % "2.2.0" % "provided",
"org.apache.hadoop" % "hadoop-mapreduce-client-core"      % "2.2.0" % "provided",
"org.apache.hadoop" % "hadoop-mapreduce-client-jobclient" % "2.2.0" % "provided",
"org.apache.hadoop" % "hadoop-mapreduce-client-core"      % "2.2.0" % "provided",
"org.apache.hadoop" % "hadoop-annotations"                % "2.2.0" % "provided",
"org.apache.avro"   % "avro-mapred"                       % "1.7.4"   classifier "hadoop2", // Note: add ' % "provided"'  if you don't need it

When you put this all together, here's is what an example build.sbt should look like:

import AssemblyKeys._

assemblySettings

name := "Scoobi Word Count"

version := "1.0"

scalaVersion := "2.10.3"

libraryDependencies ++= Seq(
    "com.nicta"                %% "scoobi"                           % "0.9.2" intransitive(),
    "org.apache.hadoop"        % "hadoop-common"                     % "2.2.0" % "provided",
    "org.apache.hadoop"        % "hadoop-hdfs"                       % "2.2.0" % "provided",
    "org.apache.hadoop"        % "hadoop-mapreduce-client-app"       % "2.2.0" % "provided",
    "org.apache.hadoop"        % "hadoop-mapreduce-client-core"      % "2.2.0" % "provided",
    "org.apache.hadoop"        % "hadoop-mapreduce-client-jobclient" % "2.2.0" % "provided",
    "org.apache.hadoop"        % "hadoop-mapreduce-client-core"      % "2.2.0" % "provided",
    "org.apache.hadoop"        % "hadoop-annotations"                % "2.2.0" % "provided",
    "org.apache.avro"          % "avro-mapred"                       % "1.7.4"    classifier "hadoop2", // Note: add ' % "provided"'  if you don't need it

    "org.scala-lang"           %  "scala-compiler"                   % "2.10.3",
    "org.scalaz"               %% "scalaz-core"                      % "7.0.2",
    "com.thoughtworks.xstream" %  "xstream"                          % "1.4.4"    intransitive(),
    "javassist"                %  "javassist"                        % "3.12.1.GA",
    "com.googlecode.kiama"     %% "kiama"                            % "1.6.0",
    "com.chuusai"              %  "shapeless_2.10.2"                 % "2.0.0-M1",
  )

resolvers ++= Seq(Resolver.sonatypeRepo("releases"),
                  Resolver.sonatypeRepo("snaspshots"))

Other Hadoop versions

Scoobi can also be used with CDH3 and CDH4. In this case you need to use the following dependencies (note the name of the Scoobi jar):

// FOR CDH3
libraryDependencies ++= Seq(
    "com.nicta"                %% "scoobi"            % "0.9.2-cdh3" intransitive(),
    "org.apache.hadoop"        %  "hadoop-core"       % "0.20.2-cdh3u1" % "provided",
    "org.apache.avro"          %  "avro-mapred"       % "1.7.4",
    "org.scala-lang"           %  "scala-compiler"    % "2.10.3",
    "com.thoughtworks.xstream" %  "xstream"           % "1.4.4"        intransitive(),
    "javassist"                %  "javassist"         % "3.12.1.GA",
    "com.googlecode.kiama"     %% "kiama"             % "1.6.0",
    "com.chuusai"              %  "shapeless_2.10.2"  % "2.0.0-M1",
  )

// FOR CDH4
libraryDependencies ++= Seq(
    "com.nicta"                %% "scoobi"            % "0.9.2-cdh4" intransitive(),
    "org.apache.hadoop"        %  "hadoop-client"     % "2.0.0-mr1-cdh4.0.1" exclude("asm", "asm") % "provided",
    "org.apache.hadoop"        %  "hadoop-core"       % "2.0.0-mr1-cdh4.0.1",                      % "provided",
    "org.apache.avro"          %  "avro-mapred"       % "1.7.4"              classifier "hadoop2",
    "org.scala-lang"           %  "scala-compiler"    % "2.10.3",
    "com.thoughtworks.xstream" %  "xstream"           % "1.4.4"              intransitive(),
    "javassist"                %  "javassist"         % "3.12.1.GA",
    "com.googlecode.kiama"     %% "kiama"             % "1.6.0",
    "com.chuusai"              %  "shapeless_2.10.2"  % "2.0.0-M1"
  )


resolvers ++= Seq(Resolver.sonatypeRepo("releases"),
                  Resolver.sonatypeRepo("snaspshots"),
                  "cloudera"             at "https://repository.cloudera.com/content/repositories/releases")

Maven assembly

Building Maven jars for Hadoop is documented in several blog posts. This one, for example, provides a step-by-step guide.

Running

Running the jar:

$ hadoop jar target/appname-assembly-version.jar scoobi

Note that there appears to be an OSX and Java 6 specific issue associated with calling hadoop in this manner requiring the jar to be added to HADOOP_CLASSPATH and then hadoop being given the correct object to run. e.g.:

$ export HADOOP_CLASSPATH=$PWD/target/appname-assembly-version.jar
$ hadoop WordCount <args>

Troubleshooting

You might get some ClassNotFoundException on the cluster if Scoobi fails to recognise that your jar contains all your dependencies (as opposed to running from sbt for example). In that case you can force the dependencies to be included in the Scoobi "job jar" that is distributed to the cluster node by turning off the dependency uploading mechanism (see the Application page):

$ hadoop WordCount <args> scoobi nolibjars