How does Hadoop DistCp work?

DistCp (distributed copy) is a tool used for large inter/intra-cluster copying. It uses MapReduce to effect its distribution, error handling and recovery, and reporting. It expands a list of files and directories into input to map tasks, each of which will copy a partition of the files specified in the source list.

Is DistCp secure?

Security settings dictate whether DistCp should be run on the source cluster or the destination cluster. The general rule-of-thumb is that if one cluster is secure and the other is not secure, DistCp should be run from the secure cluster — otherwise there may be security- related issues.

How do I enable Kerberos authentication in Hadoop?

You must restart the Hadoop daemons on the compute clients to apply the changes.

  1. Configure the krb5.conf file.
  2. Modify the hdfs-site.xml file.
  3. Modify the core-site.xml file for authentication and authorization.
  4. Modify the mapred-site.
  5. Test the Kerberos connection to the cluster.

What is difference between CP and DistCp?

2) distcp runs a MR job behind and cp command just invokes the FileSystem copy command for every file. 3) If there are existing jobs running, then distcp might take time depending memory/resources consumed by already running jobs.In this case cp would be better. 4) Also, distcp will work between 2 clusters.

How can I improve my DistCp performance?

This section includes tips for improving performance when copying large volumes of data between Amazon S3 and HDFS….‚ÄčImproving DistCp Performance

  1. Working with Local Stores.
  2. Accelerating File Listing.
  3. Controlling the Number of Mappers and Their Bandwidth.

Does DistCp overwrite?

The DistCp -overwrite option overwrites target files even if they exist at the source, or if they have the same contents. The -update and -overwrite options warrant further discussion, since their handling of source-paths varies from the defaults in a very subtle manner.

How does Kerberos authentication work?

Kerberos uses symmetric key cryptography and a key distribution center (KDC) to authenticate and verify user identities. A KDC involves three aspects: A ticket-granting server (TGS) that connects the user with the service server (SS) A Kerberos database that stores the password and identification of all verified users.

What is the most preferred way of authentication in Hadoop?

Kerberos is the basis for authentication in Hadoop secure mode. Data is encrypted as part of the authentication process. Many organizations perform authentication in the Hadoop environment by using their Active Directory or LDAP solutions.

How do I transfer data from one HDFS to another?

You can use the cp command in Hadoop. This command is similar to the Linux cp command, and it is used for copying files from one directory to another directory within the HDFS file system.

What is the difference between SAML and Kerberos?

Kerberos is a lan (enterprise) technology while SAML is Internet. Kerberos requires that the system that requests the ticket (asks for user identity, in a way )is also in the kerberos domain, SAML does not require systems to sign up before.

Which authentication is used for Kerberos?

symmetric key cryptography
Kerberos uses symmetric key cryptography and a key distribution center (KDC) to authenticate and verify user identities.

What is Kerberos authentication in Hadoop?

Hadoop uses Kerberos as the basis for strong authentication and identity propagation for both user and services. Kerberos is a third party authentication mechanism, in which users and services rely on a third party – the Kerberos server – to authenticate each to the other.