ETL4Data: Pipeline for OSM data set

Building ETLs is quite repetitive and data source specific, therefore, we want to provide an off-the-shelf set of ETLs for as many of the data sources listed in Landscape4Data as possible. This will give the user an ability to automate data harvesting and existing data updates

Set up

1. First create a directory in HDFS, on which user mapred has read and write permissions.

Example

sudo -u mapred hadoop fs -mkdir example

2. Create a directory called lib within the recently created directory.

Example

sudo -u mapred hadoop fs -mkdir example/lib

3. The Oozie workflow works with Java and Hive actions. Copy workflow.xml, job.properties and all hive scripts to directory example in HDFS.

Example

sudo -u mapred hadoop fs -put [file_to_upload] example

4. All Java programs must be compiled into jars, and it is recommended that all their dependencies are packaged in the jar as well. Copy all jars to example/lib

5. Copy the hive configuration file hive-site.xml from /etc/hive/conf/hive-site.xml to the directory example in HDFS.

6. To run the Oozie workkflow, execute the following command as mapred user:

   sudo -u mapred oozie job -oozie [oozie-server_url]/oozie -config [path to job.properties in local file system] -run

   Example

   sudo -u mapred oozie job -oozie http://udltest2.cs.ucl.ac.uk:11000/oozie -config [path to job.properties in local file system] -run

Useful links

• Oozie examples
• Oozie libraries
• OSM to Hive parser
• Oozie shell and Java actions
• Oozie scheduler
• Running Jupter Notebook on Cloudera
• OSM quality assurance
• MiniOozie