Engineering Questions with Answers - Multiple Choice Questions

MCQs on The ZooKeeper Service – 2

1 - Question

You need to have _________ installed before running ZooKeeper.
a) Java
b) C
c) C++
d) SQLGUI

View Answer

Answer: a
Explanation: Client bindings are available in several other languages.




2 - Question

Point out the correct statement.
a) All znodes are ephemeral, which means they are describing a “temporary” state
b) /hbase/replication/state contains the list of RegionServers in the main cluster
c) Offline snapshots are coordinated by the Master using ZooKeeper to communicate with the RegionServers using a two-phase-commit-like transaction
d) None of the mentioned

View Answer

Answer: a
Explanation: Although the Replication znodes do not describe a temporary state, they are meant to be the source of truth for the replication state, describing the replication state of each machine.




3 - Question

How many types of special znodes are present in Zookeeper?
a) 1
b) 2
c) 3
d) All of the mentioned

View Answer

Answer: b
Explanation: There are two special types of znode: sequential and ephemeral.




4 - Question

To register a “watch” on a znode data, you need to use the _______ commands to access the current content or metadata.
a) stat
b) put
c) receive
d) gets

View Answer
Answer: a
Explanation: ZooKeeper can also notify you of changes in a znode content or changes in a znode children.

 

 



5 - Question

Point out the wrong statement.
a) All the znodes are prefixed using the default /hbase location
b) ZooKeeper provides an interactive shell that allows you to explore the ZooKeeper state
c) The znodes that you’ll most often see are the ones that coordinate operations like Region Assignment
d) All of the mentioned

View Answer

Answer: d
Explanation: The HBase root znode path is configurable using hbase-site.xml, and by default the location is “/hbase”.




6 - Question

_______ has a design policy of using ZooKeeper only for transient data.
a) Hive
b) Imphala
c) Hbase
d) Oozie

View Answer

Answer: c
Explanation: If the HBase ZooKeeper data is removed, only the transient operations are affected – data can continue to be written and read to/from HBase.




7 - Question

Zookeeper keep track of the cluster state such as the ______ table location.
a) DOMAIN
b) NODE
c) ROOT
d) All of the mentioned

View Answer

Answer: c
Explanation: Zookeeper keeps track of list of online RegionServers, unassigned Regions.




8 - Question

The ________ master will register its own address in this znode at startup, making this znode the source of truth for identifying which server is the Master.
a) active
b) passive
c) region
d) all of the mentioned

View Answer

Answer: a
Explanation: Each inactive Master will register itself as backup Master by creating a sub-znode.




9 - Question

___________ is used to decommission more than one RegionServer at a time by creating sub-znodes.
a) /hbase/master
b) /hbase/draining
c) /hbase/passive
d) None of the mentioned

View Answer

Answer: b
Explanation: /hbase/draining lets you decommission multiple RegionServers without having the risk of regions temporarily moved to a RegionServer that will be decommissioned later.




10 - Question

The ______ znode is used for synchronizing the changes made to the _acl_ table by the grant/revoke commands.
a) zcl
b) acl
c) scl
d) bnl

View Answer

Answer: b
Explanation: Each table will have a sub-znode (/hbase/acl/tableName) containing the ACLs of the table.

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