Question 1

Agile methodologies used?

Accepted Answer

**Scrum**: 2-week sprints, standups, planning, retros, refinement. Jira for epics, stories, bugs. **Kanban**: For support and incidents—continuous flow. **Data**: Sprint on pipeline features, schema changes, quality; incidents through Kanban....

Question 2

An existing job running longer suddenly: how to analyze the issue?

Accepted Answer

**STAR approach**: **Situation**: Job ran 2 hr, now 6 hr. **Task**: Find root cause. **Analysis**: (1) Data volume growth—compare input size. (2) Skew—Spark UI shows uneven partitions. (3) Resource contention—other jobs. (4) Source throttling—DB or API limits. (5) Partition pruning—missing partitions? **Actions**: Add partitions; salting for skew; increase resources; fix source limits. **Result**: Document in runbook; add monitoring....

Question 3

How is Oozie called?

Accepted Answer

**Invocation**: (1) CLI—oozie job -run -config job.properties; (2) REST—POST /oozie/v1/jobs?action=start; (3) Hue UI; (4) Cron; (5) Sub-workflow/shell from other jobs. Example: oozie job -oozie http://host:11000/oozie -run -config workflow.properties. Oozie coordinates Hadoop jobs....

Question 4

Oozie workflow files (how many used)?

Accepted Answer

Oozie uses workflow.xml (DAG), coordinator.xml (scheduling), bundle.xml (multi-coordinator). One workflow.xml per workflow; 1–10+ per org depending on pipeline complexity. WHY: Oozie is XML-based, Hadoop-native; Airflow has largely replaced it for Python DAGs and ecosystem. SCALABILITY: Modular workflows and parameterization scale; version control in Git....

Question 5

Shell commands for renaming a file?

Accepted Answer

mv oldname newname. rename (Perl) for batch: rename 's/old/new/' *.txt. Windows: ren. mv -i for interactive overwrite. Quote names with spaces.

Question 6

Shell: change permissions?

Accepted Answer

chmod [mode] file. Numeric: 755=rwxr-xr-x. Symbolic: u+x, g-w. chmod -R 644 dir/* for recursive. chown for owner. Least privilege: 644 data, 755 exec; avoid 777.

Question 7

Shell: command to check processes running in the background?

Accepted Answer

jobs (current shell). ps aux | grep X. top, htop. pgrep -l python. nohup cmd &; then jobs or ps. kill, disown.

Question 8

Using shell, how to find the difference between two files?

Accepted Answer

diff file1 file2 (line-by-line). diff -u (unified). diff -r dir1 dir2 (recursive). cmp (byte-by-byte; exit 0 if identical). comm -3 <(sort f1) <(sort f2) for sorted common lines. Large files: md5sum/sha256sum first to skip diff if identical. WHY: diff for review; checksums for binary or quick equality....

Question 9

What type of wrapper is used, or which language is used?

Accepted Answer

**Choice depends on context.** Python (subprocess, requests)—scripting, APIs. Shell—Unix pipelines. Java/Scala—Spark jobs at scale. Node.js—event-driven. **Best practice:** Native to platform—Python for Databricks/Glue, Scala for Spark. Wrappers thin; logic in tested libs. **Scalability:** Document deps; containerize (Docker) for consistency....

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