Migrating hive from one hadoop cluster to another cluster

Recently I have migrated a hive installation from one cluster to another cluster. I havent find any
document regarding this migration. So I did it with my experience and knowledge.
Hive stores the metadata in some databases, ie it stores the data about the tables in some database.
For developement/ production grade installations, we normally use mysql/oracle/postgresql databases.
Here I am explaining about the migration of the hive with its metastore database in mysql.
The metadata contains the information about the tables. The contents of the table are stored in hdfs.
So the metadata contains hdfs uri and other details. So if we migrate hive from one cluster to another
cluster, we have to point the metadata to the hdfs of new cluster. If we haven’t do this, it will point
to the hdfs of older cluster.

For migrating a hive installation, we have to do the following things.

1) Install hive in the new hadoop cluster
2) Transfer the data present in the hive metastore directory (/user/hive/warehouse) to the new hadoop
cluster
3) take the mysql metastore dump.
4) Install mysql in the new hadoop cluster
5) Open the hive mysql-metastore dump using text readers such as notepad, notepad++ etc and search for
hdfs://ip-address-old-namenode:port and replace with hdfs://ip-address-new-namenode:port and save it.

Where ip-address-old-namenode is the ipaddress of namenode of old hadoop cluster and ip-address-
new-namenode
is the ipaddress of namenode of new hadoop cluster.

6) After doing the above steps, restore the editted mysql dump into the mysql of new hadoop cluster.
7) Configure hive as normal and do the hive schema upgradations if needed.

This is a solution that I discovered when I faced the migration issues. I dont know whether any other
standard methods are available.
This worked for me perfectly. 🙂

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About amalgjose
I am an Electrical Engineer by qualification, now I am working as a Software Engineer. I am very much interested in Electrical, Electronics, Mechanical and now in Software fields. I like exploring things in these fields. I like travelling, long drives and very much addicted to music.

7 Responses to Migrating hive from one hadoop cluster to another cluster

  1. Ajay says:

    Anyone who migrated metastore from 1 rdbms to other (like MySQL or Oracle)?

  2. Kartikeya Sinha says:

    Awesome

  3. Pingback: Sqoop Import from Hive to Hive - HTML CODE

  4. Gopi says:

    Amal, this is exactly what I wanted to validate before giving it a shot myself. Your posts are nice and helpful, have come across your posts before too. Thanks for your notes and hope you keep at it.. Thank you!

  5. Manoj Donga says:

    Needful , Thanks Amal.

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