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spark:using-python [2022/12/14 13:00] straka [Usage Examples] |
spark:using-python [2022/12/14 13:25] (current) straka [Usage Examples] |
| Consider the following simple script computing 10 most frequent words of Czech Wikipedia: | Consider the following simple script computing 10 most frequent words of Czech Wikipedia: |
| <file python> | <file python> |
| (sc.textFile("/lnet/troja/data/npfl118/wiki/cs/wiki.txt", 3*sc.defaultParallelism) | (sc.textFile("/net/projects/spark-example-data/wiki-cs", 3*sc.defaultParallelism) |
| .flatMap(lambda line: line.split()) | .flatMap(lambda line: line.split()) |
| .map(lambda word: (word, 1)) | .map(lambda word: (word, 1)) |
| * run interactive shell with local Spark cluster using one thread: | * run interactive shell with local Spark cluster using one thread: |
| <file>MASTER=local PYSPARK_DRIVER_PYTHON=ipython3 pyspark</file> | <file>MASTER=local PYSPARK_DRIVER_PYTHON=ipython3 pyspark</file> |
| * start Spark cluster (10 machines, 1GB RAM each) on SGE and run interactive shell: | * start Spark cluster (10 machines, 2GB RAM each) on Slurm and run interactive shell: |
| <file>PYSPARK_DRIVER_PYTHON=ipython3 spark-qrsh 10 1G pyspark</file> | <file>PYSPARK_DRIVER_PYTHON=ipython3 spark-srun 10 2G pyspark</file> |
| |
| Note that ''PYSPARK_DRIVER_PYTHON'' variable can be left out or specified in ''.bashrc'' (or other configuration files). | Note that ''PYSPARK_DRIVER_PYTHON'' variable can be left out or specified in ''.bashrc'' (or other configuration files). |
| .flatMap(lambda line: line.split()) | .flatMap(lambda line: line.split()) |
| .map(lambda token: (token, 1)) | .map(lambda token: (token, 1)) |
| .reduceByKey(lambda x,y: x + y) | .reduceByKey(lambda x, y: x + y) |
| .sortBy(lambda word_count: word_count[1], ascending=False) | .sortBy(lambda word_count: word_count[1], ascending=False) |
| .saveAsTextFile(output)) | .saveAsTextFile(output)) |
| </file> | </file> |
| |
| * run ''word_count.py'' script inside existing Spark cluster (i.e., inside ''spark-qsub'' or ''spark-qrsh''), or start local Spark cluster using as many threads as there are cores if there is none: | * run ''word_count.py'' script inside existing Spark cluster (i.e., inside ''spark-sbatch'' or ''spark-srun''), or start local Spark cluster using as many threads as there are cores if there is none: |
| <file>spark-submit word_count.py /net/projects/spark-example-data/wiki-cs outdir</file> | <file>spark-submit word_count.py /net/projects/spark-example-data/wiki-cs outdir</file> |
| * run ''word_count.py'' script with local Spark cluster using one thread: | * run ''word_count.py'' script with local Spark cluster using one thread: |
| <file>MASTER=local spark-submit word_count.py /net/projects/spark-example-data/wiki-cs outdir</file> | <file>MASTER=local spark-submit word_count.py /net/projects/spark-example-data/wiki-cs outdir</file> |
| * start Spark cluster (10 machines, 1GB RAM each) on SGE and run ''word_count.py'' script: | * start Spark cluster (10 machines, @GB RAM each) using Slurm and run ''word_count.py'' script: |
| <file>spark-qsub 10 1G spark-submit word_count.py /net/projects/spark-example-data/wiki-cs outdir</file> | <file>spark-sbatch 10 2G spark-submit word_count.py /net/projects/spark-example-data/wiki-cs outdir</file> |
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| ===== Using Virtual Environments ===== | ===== Using Virtual Environments ===== |