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Quick Tip on Using Sqoop Action in Oozie

Another Oozie tip blog post.

If you try to use Sqoop action in Oozie, you know you can use the “command” format, with the entire Sqoop configuration in a single line:

            import  --connect jdbc:hsqldb:file:db.hsqldb --table TT --target-dir hdfs://localhost:8020/user/tucu/foo -m 1

This is convenient, but can be difficult to read and maintain. I prefer using the “arg” syntax, with each argument in its own line:

Why Oozie?

Thats a really frequently asked question. Oozie is a workflow manager and scheduler. Most companies already have a workflow schedulers – Activebatch, Autosys, UC4, HP Orchestration. These workflow schedulers run jobs on all their existing databases – Oracle, Netezza, MySQL. Why does Hadoop need its own special workflow scheduler?

As usual, it depends. In general, you can keep using any workflow scheduler that works for you. No need to change, really.
However, Oozie does have some benefits that are worth considering:

Parameterizing Hive Actions in Oozie Workflows

Very common request I get from my customers is to parameterize the query executed by a Hive action in their Oozie workflow.
For example, the dates used in the query depend on a result of a previous action. Or maybe they depend on something completely external to the system – the operator just decides to run the workflow on specific dates.

There are many ways to do this, including using EL expressions, capturing output from shell action or java action.
Here’s an example of how to pass the parameters through the command line. This assumes that whoever triggers the workflow (Human or an external system) has the correct value and just needs to pass it to the workflow so it will be used by the query.

Here’s what the query looks like:

Using Oozie in Kerberized Cluster

In general, most Hadoop ecosystem tools work rather transparently in a kerberized cluster. Most of the time things “just work”. This includes Oozie. Still, when things don’t “just work”, they tend to fail with slightly alarming and highly ambiguous error messages. Here are few tips for using Oozie when your Hadoop cluster is kerberized. Note that this is a client/user guide. I assume you already followed the documentation on how to configure the Oozie server in the kerberized cluster (or you are using Cloudera Manager, which magically configures it for you).

Hadoop Streaming, Hue, Oozie Workflows, and Hive

Elephant Painting

MapReduce with Hadoop Streaming in bash – Bonus!