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Cloudera Hadoop Administrator Certification Certification Questions and Answer (Dumps and Practice Questions)



Question : In the YARN design, Map-Reduce is just one

: In the YARN design, Map-Reduce is just one
1. Resource Manager
2. Application
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4. None of the above

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Exp: The ApplicationMaster is the process that coordinates an application's execution in the cluster. Each application has its own unique ApplicationMaster,
which is tasked with negotiating resources (containers) from the ResourceManager and working with the NodeManager(s) to execute and monitor the
tasks. In the YARN design, Map-Reduce is just one application framework; this design permits building and deploying distributed applications using other
frameworks. For example, YARN ships with a Distributed-Shell application that allows a shell script to be run on multiple nodes on the YARN cluster.

Once the ApplicationMaster is started (as a container), it will periodically send heartbeats to the ResourceManager to affirm its health and to update the
record of its resource demands. After building a model of its requirements, the ApplicationMaster encodes its preferences and constraints in a heartbeat
message to the ResourceManager. In response to subsequent heartbeats, the ApplicationMaster will receive a lease on containers bound to an allocation
of resources at a particular node in the cluster. Depending on the containers it receives from the ResourceManager, the ApplicationMaster may update its
execution plan to accommodate the excess or lack of resources. Container allocation/deallocation can take place in a dynamic fashion as the application
progresses.






Question : Select the correct statement for HDFS in Hadoop .
: Select the correct statement for HDFS in Hadoop .
1. NameNode federation significantly improves the scalability and performance of HDFS by introducing the ability to deploy multiple NameNodes for a single cluster.
2. built-in high availability for the NameNode via a new feature called the Quorum Journal Manager (QJM). QJM-based HA features an active NameNode and a standby NameNode
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4. 1 and 3
5. 1,2 and 3

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Exp: Hadoop 2 offers significant improvements beyond YARN-namely, improvements in the HDFS (Hadoop File System) that can influence infrastructure
decisions. Whether to use NameNode federation and NameNode HA (high availability) are the two important decisions that must be made by most
organizations. NameNode federation significantly improves the scalability and performance of HDFS by introducing the ability to deploy multiple
NameNodes for a single cluster. In addition, HDFS introduces built-in high availability for the NameNode via a new feature called the Quorum Journal
Manager (QJM). QJM-based HA features an active NameNode and a standby NameNode. The standby NameNode can become active either by a manual
process or automatically. Automatic failover works in coordination with ZooKeeper. Hadoop 2 HDFS introduces the ZKFailoverController, which uses
ZooKeeper's election functionality to determine the active NameNode.






Question : In Acmeshell Inc Hadoop cluster you have slave datanodes and single Active NameNode configured.
Now suddenly you have to change some of the configuration for the all 100 slave nodes. Select the correct statement in such scenario.


: In Acmeshell Inc Hadoop cluster you have slave datanodes and single Active NameNode configured.
1. Change the slaves configuration on your NameNode .
2. Restart all 100 DataNode daemons .

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4. All the nodes including slaves and master needs to be restarted.


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Explanation: You can stop the DataNodes and TaskTrackers from NameNode's hadoop bin directory.
./hadoop-daemon.sh stop tasktracker
./hadoop-daemon.sh stop datanode
So this script checks for slaves file in conf directory of hadoop to stop the DataNodes and same with the TaskTracker.
To start To change the configuration of a DataNode daemon, you must modify the configuration file on the machine on which the daemon is running, and then restart that daemon. So to change the configuration of all datanodes, after changing the configuration files you must restart all six of the DataNodes. You do not need to restart the NameNode, since its configuration has not changed.
Again this script checks for slaves file in conf directory of hadoop to start the DataNodes and TaskTrackers.

./hadoop-daemon.sh start tasktracker
./hadoop-daemon.sh start datanode
You need to do something like this:

bin/stop-all.sh (or stop-dfs.sh and stop-yarn.sh in the 2.x serie)
rm -Rf /app/tmp/hadoop-your-username/*
bin/hadoop namenode -format (or hdfs in the 2.x serie)



Related Questions

Question :

The ApplicationMaster has to emit __________ to the ResourceManager to keep it informed that the ApplicationMaster is alive and still running.



 :
1. heartbeats
2. messages
3. events
4. Async Messages



Question :
A _____ is the basic unit of processing capacity in YARN, and is an encapsulation of resource elements (memory, cpu etc.)

 :
1. Node Manager
2. Container
3. ApplicationMaster
4. DataNode


Question :

Select the correct option which is/are correct


 :
1. YARN takes into account all of the available compute resources on each machine in the cluster.
2. Based on the available resources, YARN negotiates resource requests from applications (such as MapReduce) running in the cluster.
3. YARN then provides processing capacity to each application by allocating Containers.
4. 1 and 3
5. 1,2 and 3


Question : As a general recommendation, allowing for ______ Containers per disk and per core gives the best balance for cluster utilization.

 : As a general recommendation, allowing for ______ Containers per disk and per core gives the best balance for cluster utilization.
1. One
2. Two
3. Three
4. Four



Question : In the Hadoop . framework, if HBase is also running on the same node for which available RAM is GB, so what is the ideal configuration
for "Reserved System Memory"

 : In the Hadoop . framework, if HBase is also running on the same node for which available RAM is GB, so what is the ideal configuration
1. 1GB
2. 2GB
3. 3GB
4. No need to reserve


Question : The next calculation is to determine the maximum number of containers allowed per node. The following formula can be used:

# of containers = min (2*CORES, 1.8*DISKS, (Total available RAM) / MIN_CONTAINER_SIZE)

Where MIN_CONTAINER_SIZE is the minimum container size (in RAM). This value is dependent on the amount of RAM available -- in smaller memory nodes, the minimum container size should also be smaller

Available Total RAM per Node"is 24GB, then what is the "Recommended Minimum Container Size"


 : The next calculation is to determine the maximum number of containers allowed per node. The following formula can be used:
1. 256MB
2. 512MB
3. 1024MB
4. 2048 MB