Migrate from Legacy Hadoop

Hadoop to Databricks migration

Cloudera, Hortonworks, MapR

Cover illustration: Hadoop to Databricks migration
Short answer

A Hadoop to Databricks migration moves HDFS data, Hive tables, Spark and MapReduce jobs, Oozie workflows and Ranger or Sentry policies to a governed cloud lakehouse. Spark jobs usually move with small changes; MapReduce and Oozie logic is rebuilt as declarative pipelines and Lakeflow Jobs.

What we move

HDFS data, Hive tables, Spark and MapReduce jobs, Oozie workflows, Ranger and Sentry policies

Value after the move

  • Retire costly on-premise clusters and their upgrades
  • Keep Spark skills while dropping cluster babysitting
  • One governance model in Unity Catalog instead of Ranger and Sentry

How Legacy Hadoop maps to Databricks

Each component has a clear target on the Databricks Data Intelligence Platform.

Legacy HadoopDatabricks
HDFSCloud object storage with Delta Lake tables
Hive tables and Hive MetastoreDelta tables in Unity Catalog
Spark on YARNServerless or job compute
MapReduce jobsSpark code or Lakeflow Declarative Pipelines
Oozie workflowsLakeflow Jobs
Impala queriesDatabricks SQL warehouses
Ranger or Sentry policiesUnity Catalog permissions and audit

How we run the migration

  1. Assess

    Inventory every table, job, report and user. Map dependencies, find what is unused, and estimate effort and cost.

    Output: Migration assessment and business case
  2. Plan

    Design the target lakehouse, governance and security. Group workloads into waves by value and risk.

    Output: Target architecture and wave plan
  3. Convert

    Convert SQL and ETL with LakeBridge and our accelerators, then review and test the output.

    Output: Converted, tested code per wave
  4. Reconcile

    Run old and new side by side and compare results table by table until they match.

    Output: Signed-off reconciliation reports
  5. Cut over and optimize

    Move users in waves, retire the old system, then tune cost and performance.

    Output: Decommission plan and FinOps baseline

We use Databricks LakeBridge for profiling, code conversion and reconciliation, alongside our own accelerators and engineer review of every critical path.

Go deeper

FAQ

Hadoop to Databricks migration: FAQ

How long does a Hadoop to Databricks migration take?

It depends on the number of tables, jobs and users. We start with a short, fixed-scope assessment that inventories the cluster and produces a wave plan with effort and cost estimates.

Do we have to rewrite our Spark jobs?

Usually not. Most Spark jobs move with small changes. MapReduce jobs, Oozie workflows and custom scripts are the parts that need rewriting.

What happens to our Ranger or Sentry security policies?

We map them to Unity Catalog permissions, then add lineage and audit that Hadoop did not provide.

Other migration paths