CCA-500 Exam Dumps - Cloudera Certified Administrator for Apache Hadoop (CCAH)

Hdfs fs –du

Hdfs fsck

Dskchk

The map-only checksum

Hadoop does not provide any tools to discover missing or corrupt data; there is not need because three replicas are kept for each data block

Cached by the NodeManager managing the job containers, then written to a log directory on the NameNode

Cached in the YARN container running the task, then copied into HDFS on job completion

In HDFS, in the directory of the user who generates the job

On the local disk of the slave mode running the task

User authentication on all remote procedure calls (RPCs)

Encryption for data during transfer between the Mappers and Reducers

Encryption for data on disk (“at rest”)

Authentication for user access to the cluster against a central server

Root access to the cluster for users hdfs and mapred but non-root access for clients

SampleJar.Jar is sent to the ApplicationMaster which allocates a container for SampleJar.Jar

Sample.jar is placed in a temporary directory in HDFS

SampleJar.jar is sent directly to the ResourceManager

SampleJar.jar is serialized into an XML file which is submitted to the ApplicatoionMaster

The NameNode will update the dfs.hosts property to include machines running the DataNode daemon on the next NameNode reboot or with the command dfsadmin –refreshNodes

No new nodes can be added to the cluster until you specify them in the dfs.hosts file

Any machine running the DataNode daemon can immediately join the cluster

Presented with a blank dfs.hosts property, the NameNode will permit DataNodes specified in mapred.hosts to join the cluster

For a 1GB child heap size an io.sort.mb of 128 MB will always maximize memory to disk I/O

Increase the io.sort.mb to 1GB

Decrease the io.sort.mb value to 0

Tune the io.sort.mb value until you observe that the number of spilled records equals (or is as close to equals) the number of map output records.