Apache Spark - A unified analytics engine for large-scale data processing
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WeichenXu 3b14088541 [SPARK-26175][PYTHON] Redirect the standard input of the forked child to devnull in daemon
## What changes were proposed in this pull request?

PySpark worker daemon reads from stdin the worker PIDs to kill. 1bb60ab839/python/pyspark/daemon.py (L127)

However, the worker process is a forked process from the worker daemon process and we didn't close stdin on the child after fork. This means the child and user program can read stdin as well, which blocks daemon from receiving the PID to kill. This can cause issues because the task reaper might detect the task was not terminated and eventually kill the JVM.

This PR fix this by redirecting the standard input of the forked child to devnull.

## How was this patch tested?

Manually test.

In `pyspark`, run:
```
import subprocess
def task(_):
  subprocess.check_output(["cat"])

sc.parallelize(range(1), 1).mapPartitions(task).count()
```

Before:
The job will get stuck and press Ctrl+C to exit the job but the python worker process do not exit.
After:
The job finish correctly. The "cat" print nothing (because the dummay stdin is "/dev/null").
The python worker process exit normally.

Please review https://spark.apache.org/contributing.html before opening a pull request.

Closes #25138 from WeichenXu123/SPARK-26175.

Authored-by: WeichenXu <weichen.xu@databricks.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-07-31 09:10:24 +09:00
.github [MINOR][DOCS] Tighten up some key links to the project and download pages to use HTTPS 2019-05-21 10:56:42 -07:00
assembly [SPARK-27300][GRAPH] Add Spark Graph modules and dependencies 2019-06-09 00:26:26 -07:00
bin [SPARK-28525][DEPLOY] Allow Launcher to be applied Java options 2019-07-30 12:45:32 -07:00
build [SPARK-27979][BUILD][test-maven] Remove deprecated --force option in build/mvn and run-tests.py 2019-06-10 18:40:46 -07:00
common [SPARK-28107][SQL] Support 'DAY TO (HOUR|MINUTE|SECOND)', 'HOUR TO (MINUTE|SECOND)' and 'MINUTE TO SECOND' 2019-07-10 18:01:42 -07:00
conf [SPARK-28525][DEPLOY] Allow Launcher to be applied Java options 2019-07-30 12:45:32 -07:00
core [SPARK-28209][CORE][SHUFFLE] Proposed new shuffle writer API 2019-07-30 14:17:30 -07:00
data [SPARK-22666][ML][SQL] Spark datasource for image format 2018-09-05 11:59:00 -07:00
dev [SPARK-28549][BUILD][CORE][SQL] Use text.StringEscapeUtils instead lang3.StringEscapeUtils 2019-07-29 11:45:29 +09:00
docs [SPARK-28399][ML][PYTHON] implement RobustScaler 2019-07-30 10:24:33 -05:00
examples [SPARK-28399][ML][PYTHON] implement RobustScaler 2019-07-30 10:24:33 -05:00
external [SPARK-28489][SS] Fix a bug that KafkaOffsetRangeCalculator.getRanges may drop offsets 2019-07-26 00:10:56 -07:00
graph [SPARK-27300][GRAPH] Add Spark Graph modules and dependencies 2019-06-09 00:26:26 -07:00
graphx [SPARK-27682][CORE][GRAPHX][MLLIB] Replace use of collections and methods that will be removed in Scala 2.13 with work-alikes 2019-05-15 09:29:12 -05:00
hadoop-cloud [SPARK-28187][BUILD] Add support for hadoop-cloud to the PR builder. 2019-06-27 15:59:05 -07:00
launcher [SPARK-28525][DEPLOY] Allow Launcher to be applied Java options 2019-07-30 12:45:32 -07:00
licenses [SPARK-27557][DOC] Add copy button to Python API docs for easier copying of code-blocks 2019-05-01 11:26:18 -05:00
licenses-binary [SPARK-27358][UI] Update jquery to 1.12.x to pick up security fixes 2019-04-05 12:54:01 -05:00
mllib [SPARK-28399][ML][PYTHON] implement RobustScaler 2019-07-30 10:24:33 -05:00
mllib-local [SPARK-28421][ML] SparseVector.apply performance optimization 2019-07-23 20:20:22 -05:00
project [SPARK-28556][SQL] QueryExecutionListener should also notify Error 2019-07-30 11:47:36 +09:00
python [SPARK-26175][PYTHON] Redirect the standard input of the forked child to devnull in daemon 2019-07-31 09:10:24 +09:00
R [SPARK-28471][SQL] Replace yyyy by uuuu in date-timestamp patterns without era 2019-07-28 20:36:36 -07:00
repl [SPARK-28549][BUILD][CORE][SQL] Use text.StringEscapeUtils instead lang3.StringEscapeUtils 2019-07-29 11:45:29 +09:00
resource-managers [SPARK-28550][K8S][TESTS] Unset SPARK_HOME environment variable in K8S integration preparation 2019-07-29 10:47:28 -07:00
sbin [SPARK-28164] Fix usage description of start-slave.sh 2019-06-26 12:42:33 -05:00
sql [SPARK-28375][SQL] Make pullupCorrelatedPredicate idempotent 2019-07-30 16:29:24 -07:00
streaming [SPARK-28549][BUILD][CORE][SQL] Use text.StringEscapeUtils instead lang3.StringEscapeUtils 2019-07-29 11:45:29 +09:00
tools [SPARK-25956] Make Scala 2.12 as default Scala version in Spark 3.0 2018-11-14 16:22:23 -08:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [MINOR][DOC] Documentation on JVM options for SBT 2019-01-22 18:27:24 -06:00
appveyor.yml [SPARK-28309][R][INFRA] Fix AppVeyor to run SparkR tests by avoiding to use devtools for testthat 2019-07-09 12:06:46 +09:00
CONTRIBUTING.md [MINOR][DOCS] Tighten up some key links to the project and download pages to use HTTPS 2019-05-21 10:56:42 -07:00
LICENSE [SPARK-27557][DOC] Add copy button to Python API docs for easier copying of code-blocks 2019-05-01 11:26:18 -05:00
LICENSE-binary [SPARK-27300][GRAPH] Add Spark Graph modules and dependencies 2019-06-09 00:26:26 -07:00
NOTICE [SPARK-23654][BUILD] remove jets3t as a dependency of spark 2018-08-16 12:34:23 -07:00
NOTICE-binary [SPARK-27862][BUILD] Move to json4s 3.6.6 2019-05-30 19:42:56 -05:00
pom.xml [SPARK-28544][BUILD] Update zstd-jni to 1.4.2-1 2019-07-27 18:08:20 -07:00
README.md [SPARK-28473][DOC] Stylistic consistency of build command in README 2019-07-23 16:29:46 -07:00
scalastyle-config.xml [SPARK-25986][BUILD] Add rules to ban throw Errors in application code 2018-11-14 13:05:18 -08:00

Apache Spark

Spark is a unified analytics engine for large-scale data processing. It provides high-level APIs in Scala, Java, Python, and R, and an optimized engine that supports general computation graphs for data analysis. It also supports a rich set of higher-level tools including Spark SQL for SQL and DataFrames, MLlib for machine learning, GraphX for graph processing, and Structured Streaming for stream processing.

https://spark.apache.org/

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Online Documentation

You can find the latest Spark documentation, including a programming guide, on the project web page. This README file only contains basic setup instructions.

Building Spark

Spark is built using Apache Maven. To build Spark and its example programs, run:

./build/mvn -DskipTests clean package

(You do not need to do this if you downloaded a pre-built package.)

You can build Spark using more than one thread by using the -T option with Maven, see "Parallel builds in Maven 3". More detailed documentation is available from the project site, at "Building Spark".

For general development tips, including info on developing Spark using an IDE, see "Useful Developer Tools".

Interactive Scala Shell

The easiest way to start using Spark is through the Scala shell:

./bin/spark-shell

Try the following command, which should return 1,000,000,000:

scala> spark.range(1000 * 1000 * 1000).count()

Interactive Python Shell

Alternatively, if you prefer Python, you can use the Python shell:

./bin/pyspark

And run the following command, which should also return 1,000,000,000:

>>> spark.range(1000 * 1000 * 1000).count()

Example Programs

Spark also comes with several sample programs in the examples directory. To run one of them, use ./bin/run-example <class> [params]. For example:

./bin/run-example SparkPi

will run the Pi example locally.

You can set the MASTER environment variable when running examples to submit examples to a cluster. This can be a mesos:// or spark:// URL, "yarn" to run on YARN, and "local" to run locally with one thread, or "local[N]" to run locally with N threads. You can also use an abbreviated class name if the class is in the examples package. For instance:

MASTER=spark://host:7077 ./bin/run-example SparkPi

Many of the example programs print usage help if no params are given.

Running Tests

Testing first requires building Spark. Once Spark is built, tests can be run using:

./dev/run-tests

Please see the guidance on how to run tests for a module, or individual tests.

There is also a Kubernetes integration test, see resource-managers/kubernetes/integration-tests/README.md

A Note About Hadoop Versions

Spark uses the Hadoop core library to talk to HDFS and other Hadoop-supported storage systems. Because the protocols have changed in different versions of Hadoop, you must build Spark against the same version that your cluster runs.

Please refer to the build documentation at "Specifying the Hadoop Version and Enabling YARN" for detailed guidance on building for a particular distribution of Hadoop, including building for particular Hive and Hive Thriftserver distributions.

Configuration

Please refer to the Configuration Guide in the online documentation for an overview on how to configure Spark.

Contributing

Please review the Contribution to Spark guide for information on how to get started contributing to the project.