I have imported a table using sqoop and saved it as a sequence file.
How do I read this file into an RDD or Dataframe?
I have tried sc.sequenceFile() but I'm not sure what to pass as keyClass and value Class. I tried tried using org.apache.hadoop.io.Text, org.apache.hadoop.io.LongWritable for keyClass and valueClass
but it did not work. I am using pyspark for reading the files.
in python its not working however in SCALA it works:
You need to do following steps:
step1:
If you are importing as sequence file from sqoop, there is a jar file generated, you need to use that as ValueClass while reading sequencefile. This jar file is generally placed in /tmp folder, but you can redirect it to a specific folder (i.e. to local folder not hdfs) using --bindir option.
example:
sqoop import --connect jdbc:mysql://ms.itversity.com/retail_export --
username retail_user --password itversity --table customers -m 1 --target-dir '/user/srikarthik/udemy/practice4/problem2/outputseq' --as-sequencefile --delete-target-dir --bindir /home/srikarthik/sqoopjars/
step2:
Also, you need to download the jar file from below link:
http://www.java2s.com/Code/Jar/s/Downloadsqoop144hadoop200jar.htm
step3:
Suppose, customers table is imported using sqoop as sequence file.
Run spark-shell --jars path-to-customers.jar,sqoop-1.4.4-hadoop200.jar
example:
spark-shell --master yarn --jars /home/srikarthik/sqoopjars/customers.jar,/home/srikarthik/tejdata/kjar/sqoop-1.4.4-hadoop200.jar
step4: Now run below commands inside the spark-shell
scala> import org.apache.hadoop.io.LongWritable
scala> val data = sc.sequenceFile[LongWritable,customers]("/user/srikarthik/udemy/practice4/problem2/outputseq")
scala> data.map(tup => (tup._1.get(), tup._2.toString())).collect.foreach(println)
You can use SeqDataSourceV2 package to read the sequence file with the DataFrame API without any prior knowledge of the schema (aka keyClass and valueClass).
Please note that the current version is only compatible with Spark 2.4
$ pyspark --packages seq-datasource-v2-0.2.0.jar
df = spark.read.format("seq").load("data.seq")
df.show()
Related
We are using Spark-Shell REPL Mode to test various use-cases and connecting to multiple sources/sinks
We need to add custom drivers/jars in spark-defaults.conf file, I have tried to add multiple jars separated by comma
like
spark.driver.extraClassPath = /home/sandeep/mysql-connector-java-5.1.36.jar
spark.executor.extraClassPath = /home/sandeep/mysql-connector-java-5.1.36.jar
But its not working, Can anyone please provide details for correct syntax
Note: Verified in Linux Mint and Spark 3.0.1
If you are setting properties in spark-defaults.conf, spark will take those settings only when you submit your job using spark-submit.
Note: spark-shell and pyspark need to verify.
file: spark-defaults.conf
spark.driver.extraJavaOptions -Dlog4j.configuration=file:log4j.properties -Dspark.yarn.app.container.log.dir=app-logs -Dlogfile.name=hello-spark
spark.jars.packages org.apache.spark:spark-sql-kafka-0-10_2.12:3.0.1,org.apache.spark:spark-avro_2.12:3.0.1
In the terminal run your job say wordcount.py
spark-submit /path-to-file/wordcount.py
If you want to run your job in development mode from an IDE then you should use config() method. Here we will set Kafka jar packages and avro package. Also if you want to include log4j.properties, then use extraJavaOptions.
AppName and master can be provided in 2 way.
use .appName() and .master()
use .conf file
file: hellospark.py
from logger import Log4j
from util import get_spark_app_config
from pyspark.sql import SparkSession
# first approach.
spark = SparkSession.builder \
.appName('Hello Spark') \
.master('local[3]') \
.config("spark.streaming.stopGracefullyOnShutdown", "true") \
.config("spark.jars.packages",
"org.apache.spark:spark-sql-kafka-0-10_2.12:3.0.1,
org.apache.spark:spark-avro_2.12:3.0.1") \
.config("spark.driver.extraJavaOptions",
"-Dlog4j.configuration=file:log4j.properties "
"-Dspark.yarn.app.container.log.dir=app-logs "
"-Dlogfile.name=hello-spark") \
.getOrCreate()
# second approach.
conf = get_spark_app_config()
spark = SparkSession.builder \
.config(conf=conf)
.config("spark.jars.packages",
"org.apache.spark:spark-sql-kafka-0-10_2.12:3.0.1") \
.getOrCreate()
logger = Log4j(spark)
file: logger.py
from pyspark.sql import SparkSession
class Log4j(object):
def __init__(self, spark: SparkSession):
conf = spark.sparkContext.getConf()
app_name = conf.get("spark.app.name")
log4j = spark._jvm.org.apache.log4j
self.logger = log4j.LogManager.getLogger(app_name)
def warn(self, message):
self.logger.warn(message)
def info(self, message):
self.logger.info(message)
def error(self, message):
self.logger.error(message)
def debug(self, message):
self.logger.debug(message)
file: util.py
import configparser
from pyspark import SparkConf
def get_spark_app_config(enable_delta_lake=False):
"""
It will read configuration from spark.conf file to create
an instance of SparkConf(). Can be used to create
SparkSession.builder.config(conf=conf).getOrCreate()
:return: instance of SparkConf()
"""
spark_conf = SparkConf()
config = configparser.ConfigParser()
config.read("spark.conf")
for (key, value) in config.items("SPARK_APP_CONFIGS"):
spark_conf.set(key, value))
if enable_delta_lake:
for (key, value) in config.items("DELTA_LAKE_CONFIGS"):
spark_conf.set(key, value)
return spark_conf
file: spark.conf
[SPARK_APP_CONFIGS]
spark.app.name = Hello Spark
spark.master = local[3]
spark.sql.shuffle.partitions = 3
[DELTA_LAKE_CONFIGS]
spark.jars.packages = io.delta:delta-core_2.12:0.7.0
spark.sql.extensions = io.delta.sql.DeltaSparkSessionExtension
spark.sql.catalog.spark_catalog = org.apache.spark.sql.delta.catalog.DeltaCatalog
As an example in addition to Prateek's answer, I have had some success by adding the following to the spark-defaults.conf file to be loaded when starting a spark-shell session in client mode.
spark.jars jars_added/aws-java-sdk-1.7.4.jar,jars_added/hadoop-aws-2.7.3.jar,jars_added/sqljdbc42.jar,jars_added/jtds-1.3.1.jar
Adding the exact line to the spark-defaults.conf file will load the three jar files as long as they are stored in the jars_added folder when spark-shell is run from the specific directory (doing this for me seems to mitigate the need to have the jar files loaded onto the slaves in the specified locations as well). I created the folder 'jars_added' in my $SPARK_HOME directory so whenever I run spark-shell I must run it from this directory (I have not yet worked out how to change the location the spark.jars setting uses as the initial path, it seems to default to the current directory when launching spark-shell). As hinted at by Prateek the jar files need to be comma separated.
I also had to set SPARK_CONF_DIR to $SPARK_HOME/conf (export SPARK_CONF_DIR = "${SPARK_HOME}/conf") for spark-shell to recognise the location of my config file (i.e. spark-defaults.conf). I'm using PuTTY to ssh onto the master.
Just to clarify once I have added the spark.jars jar1, jar2, jar3 to my spark-defaults.conf file I type the following to start my spark-shell session:
cd $SPARK_HOME //navigate to the spark home directory which contains the jars_added folder
spark-shell
On start up the spark-shell then loads the specified jar files from the jars_added folder
I'm trying to start use DeltaLakes using Pyspark.
To be able to use deltalake, I invoke pyspark on Anaconda shell-prompt as —
pyspark — packages io.delta:delta-core_2.11:0.3.0
Here is the reference from deltalake — https://docs.delta.io/latest/quick-start.html
All commands for delta lake works fine from Anaconda shell-prompt.
On jupyter notebook, reference to a deltalake table gives error.Here is the code I am running on Jupyter Notebook -
df_advisorMetrics.write.mode("overwrite").format("delta").save("/DeltaLake/METRICS_F_DELTA")
spark.sql("create table METRICS_F_DELTA using delta location '/DeltaLake/METRICS_F_DELTA'")
Below is the code I am using at start of notebook to connect to pyspark -
import findspark
findspark.init()
findspark.find()
import pyspark
findspark.find()
Below is the error I get:
Py4JJavaError: An error occurred while calling o116.save.
: java.lang.ClassNotFoundException: Failed to find data source: delta. Please find packages at http://spark.apache.org/third-party-projects.html
Any suggestions?
I have created a Google Colab/Jupyter Notebook example that shows how to run Delta Lake.
https://github.com/prasannakumar2012/spark_experiments/blob/master/examples/Delta_Lake.ipynb
It has all the steps needed to run. This uses the latest spark and delta version. Please change the versions accordingly.
A potential solution is to follow the techniques noted in Import PySpark packages with a regular Jupyter notebook.
Another potential solution is to download the delta-core JAR and place it in the $SPARK_HOME/jars folder so when you run jupyter notebook it automatically includes the Delta Lake JAR.
I use DeltaLake all the time from a Jupyter notebook.
Try the following in you Jupyter notebook running Python 3.x.
### import Spark libraries
from pyspark.sql import SparkSession
import pyspark.sql.functions as F
### spark package maven coordinates - in case you are loading more than just delta
spark_packages_list = [
'io.delta:delta-core_2.11:0.6.1',
]
spark_packages = ",".join(spark_packages_list)
### SparkSession
spark = (
SparkSession.builder
.config("spark.jars.packages", spark_packages)
.config("spark.delta.logStore.class", "org.apache.spark.sql.delta.storage.S3SingleDriverLogStore")
.config("spark.sql.extensions", "io.delta.sql.DeltaSparkSessionExtension")
.config("spark.sql.catalog.spark_catalog", "org.apache.spark.sql.delta.catalog.DeltaCatalog")
.getOrCreate()
)
sc = spark.sparkContext
### Python library in delta jar.
### Must create sparkSession before import
from delta.tables import *
Assuming you have a spark dataframe df
HDFS
Save
### overwrite, change mode="append" if you prefer
(df.write.format("delta")
.save("my_delta_file", mode="overwrite", partitionBy="partition_column_name")
)
Load
df_delta = spark.read.format("delta").load("my_delta_file")
AWS S3 ObjectStore
Initial S3 setup
### Spark S3 access
hdpConf = sc._jsc.hadoopConfiguration()
user = os.getenv("USER")
### Assuming you have your AWS credentials in a jceks keystore.
hdpConf.set("hadoop.security.credential.provider.path", f"jceks://hdfs/user/{user}/awskeyfile.jceks")
hdpConf.set("fs.s3a.fast.upload", "true")
### optimize s3 bucket-level parquet column selection
### un-comment to use
# hdpConf.set("fs.s3a.experimental.fadvise", "random")
### Pick one upload buffer option
hdpConf.set("fs.s3a.fast.upload.buffer", "bytebuffer") # JVM off-heap memory
# hdpConf.set("fs.s3a.fast.upload.buffer", "array") # JVM on-heap memory
# hdpConf.set("fs.s3a.fast.upload.buffer", "disk") # DEFAULT - directories listed in fs.s3a.buffer.dir
s3_bucket_path = "s3a://your-bucket-name"
s3_delta_prefix = "delta" # or whatever
Save
### overwrite, change mode="append" if you prefer
(df.write.format("delta")
.save(f"{s3_bucket_path}/{s3_delta_prefix}/", mode="overwrite", partitionBy="partition_column_name")
)
Load
df_delta = spark.read.format("delta").load(f"{s3_bucket_path}/{s3_delta_prefix}/")
Spark Submit
Not directly answering the original question, but for completeness, you can do the following as well.
Add the following to your spark-defaults.conf file
spark.jars.packages io.delta:delta-core_2.11:0.6.1
spark.delta.logStore.class org.apache.spark.sql.delta.storage.S3SingleDriverLogStore
spark.sql.extensions io.delta.sql.DeltaSparkSessionExtension
spark.sql.catalog.spark_catalog org.apache.spark.sql.delta.catalog.DeltaCatalog
Refer to conf file in spark-submit command
spark-submit \
--properties-file /path/to/your/spark-defaults.conf \
--name your_spark_delta_app \
--py-files /path/to/your/supporting_pyspark_files.zip \
--class Main /path/to/your/pyspark_script.py
I'm struggling to understand how to import files as libraries with pyspark.
Let's say that I have the following
HappyBirthday.py
def run():
print('Happy Birthday!')
sparky.py
from pyspark import SparkContext, SparkConf
from pyspark.sql import SparkSession
import HappyBirthday
sc = SparkContext(appName="kmeans")
HappyBirthday.run()
sc.stop()
And both of them are stored in the same folder in S3.
How I make sure that, when I use
spark-submit --deploy-mode cluster s3://<PATH TO FILE>/sparky.py
, HappyBirthday.py is also imported?
If you are trying to run sparky.py and use a function inside HappyBirthday.py, you can try something like this.
spark-submit \
--deploy-mode cluster --master yarn \
--py-files s3://<PATH TO FILE>/HappyBirthday.py \
s3://<PATH TO FILE>/sparky.py
Just remember that s3 does not have the concept of "folders", so you just need to provide the exact path of the files or the group of files.
In case you have a whole bunch of dependencies in your project, you can bundle them all up into a single .zip file with the necessary init.py files and you can import any of the functions inside the libraries.
For example - I have sqlparse library as a dependency, with a bunch of python file s inside it. I have a package zip file, like below.
unzip -l packages.zip
Archive: packages.zip
0 05-05-2019 12:44 sqlparse/
2249 05-05-2019 12:44 sqlparse/__init__.py
5916 05-05-2019 12:44 sqlparse/cli.py
...
110 05-05-2019 12:44 sqlparse-0.3.0.dist-info/WHEEL
--------- -------
125034 38 files
This is uploaded to S3 and then used in the job.
spark-submit --deploy-mode cluster --master yarn --py-files s3://my0-test-bucket/artifacts/packages.zip s3://my-test-script/script/script.py
My file can contain imports like below.
import pyspark
import sqlparse # Importing the library
from pprint import pprint
What you want to use here is the --py-files argument for spark-submit. From the submitting applications page in the Spark documentation:
For Python, you can use the --py-files argument of spark-submit to add .py, .zip or .egg files to be distributed with your application. If you depend on multiple Python files we recommend packaging them into a .zip or .egg.
For your example, this would be:
spark-submit --deploy-mode cluster --py-files s3://<PATH TO FILE>/sparky.py
I am running both hadoop and spark and I want to use files from hdfs as an argument on spark-submit, so I made a folder in hdfs with the files
eg. /user/hduser/test/input
and I want to run spark-submit like this:
$SPARK_HOME/bin/spark-submit --master spark://admin:7077 ./target/scala-2.10/test_2.10-1.0.jar hdfs://user/hduser/test/input
but I cant make it work, what's the right way to do it?
the error I am getting is :
WARN FileInputDStream: Error finding new files
java.lang.NullPointerException
Check if you are able to access HDFS from Spark code, If yes then you need to add following line of code in your Scala import.
import org.apache.hadoop.fs.FileSystem
import org.apache.hadoop.fs.Path
import org.apache.spark.SparkFiles
then in your code add following lines
var hadoopConf = new org.apache.hadoop.conf.Configuration()
var fileSystem = FileSystem.get(hadoopConf)
var path = new Path(args(0))
actually the problem was the path. I had to use hdfs://localhost:9000/user/hduser/...
I am trying to copy the retail_db database tables into hive database which I already created. When I execute the following code
sqoop import-all-tables \
--num-mappers 1 \
--connect "jdbc:mysql://quickstart.cloudera:3306/retail_db" \
--username=retail_dba \
--password=cloudera \
--hive-import \
--hive-overwrite \
--create-hive-table \
--outdir java_files \
--hive-database retail_stage
My Map-reduce job stops with the following error:
ERROR tool.ImportAllTablesTool: Encountered IOException running import
job: org.apache.hadoop.mapred.FileAlreadyExistsException: Output
directory hdfs://quickstart.cloudera:8020/user/cloudera/categories
already exists
I am trying to copy the tables to hive database,Then why an existing file in cloudera caused the problem. Is there a way to ignore this error or overwrite the existing file.
This is how sqoop imports job works:
sqoop creates/imports data in tmp dir(HDFS) which is user's home dir(in your case it is /user/cloudera).
Then copy data to its actual hive location (i.e., /user/hive/wearhouse.
This categories dir should have exist before you ran import statements. so delete that dir or rename it if its important.
hadoop fs -rmr /user/cloudera/categories
OR
hadoop fs -mv /user/cloudera/categories /user/cloudera/categories_1
and re-run sqoop command!
So in short, Importing to Hive will use hdfs as the staging place and sqoop deletes staging dir /user/cloudera/categories after copying(sucessfully) to actual hdfs location - it is last stage of sqoop job to clean up staging/tmp files - so if you try to list the tmp staging dir, you won't find it.
After successful import: hadoop fs -ls /user/cloudera/categories - dir will not be there.
Sqoop import to Hive works in 3 steps:
Put data to HDFS
Create Hive table if not exists
Load data into Hive Table
You have not mentioned --target-dir or --warehouse-dir, so it will put data in HDFS Home Directory which I believe /user/cloudera/ in your case.
Now for a MySQL table categories you might have imported it earlier. So, /user/cloudera/categories directory exists and you are getting this exception.
Add any non-existing directory in --taget-dir like --taget-dir /user/cloudera/mysqldata. Then sqoop will put all the Mysql Tables imported by above command in this location.
Based on answer #1 above, I found this. I tried and it works.
So, just add --delete-target-dir
You cannot use hive-import and hive-overwrite at the same time.
The version I confirmed this issue is;
$ sqoop help import
--hive-overwrite Overwrite existing data in
the Hive table
$ sqoop version
Sqoop 1.4.6-cdh5.13.0
ref. https://stackoverflow.com/a/22407835/927387