LinkedIn 技能评估答案和问题 — Hadoop
Hadoop is a popular framework for processing large-scale data sets using distributed computing. Many companies use Hadoop to store, 管理和分析他们的数据, 他们需要能够使用这项技术的熟练专业人员. If you want to prove your Hadoop skills and get certified by LinkedIn, you need to pass the LinkedIn skill assessment test 对于 Hadoop. This test consists of multiple-choice questions that cover various topics related to Hadoop, such as its architecture, 组件, 命令, 配置, 和更多.
To help you prepare for this test, I have compiled a list of questions and answers that you may encounter in the exam. These questions and answers are based on my own experience and research, and they are not official or endorsed by LinkedIn. 然而, they can give you an idea of what to expect and how to answer the questions correctly. 这里有 问题 和 答案 为了 LinkedIn skill assessment test for Hadoop.
第一季度. Partitioner controls the partitioning of what data?
- final keys
- final values
- intermediate keys
- intermediate values
SQL Windowing functions are implemented in Hive using which keywords?
Q2.- UNION DISTINCT, RANK
- 超过, RANK
- 超过, EXCEPT
- UNION DISTINCT, RANK
Rather than adding a Secondary Sort to a slow Reduce job, it is Hadoop best practice to perform which optimization?
Q3.- Add a partitioned shuffle to the Map job.
- Add a partitioned shuffle to the Reduce job.
- Break the Reduce job into multiple, chained Reduce jobs.
- Break the Reduce job into multiple, chained Map jobs.
Hadoop Auth enforces authentication on protected resources. Once authentication has been established, it sets what type of authenticating cookie?
第四季度.- encrypted HTTP
- unsigned HTTP
- compressed HTTP
- signed HTTP
MapReduce jobs can be written in which language?
Q5.- Java or Python
- SQL only
- SQL or Java
- Python or SQL
To perform local aggregation of the intermediate outputs, MapReduce users can optionally specify which object?
Q6.- Reducer
- Combiner
- Mapper
- 柜台
To verify job status, look for the value ___
在里面 ___
.
Q7. - SUCCEEDED; syslog
- SUCCEEDED; stdout
- DONE; syslog
- DONE; stdout
Which line of code implements a Reducer method in MapReduce 2.0?
Q8.- public void reduce(Text key, Iterator values, Context context){...}
- public static void reduce(Text key, IntWritable[] 值, Context context){...}
- public static void reduce(Text key, Iterator values, Context context){...}
- public void reduce(Text key, IntWritable[] 值, Context context){...}
To get the total number of mapped input records in a map job task, you should review the value of which counter?
Q9.- FileInputFormatCounter
- FileSystemCounter
- JobCounter
- TaskCounter (NOT SURE)
Hadoop Core supports which CAP capabilities?
辅酶Q10.- 一个, P
- C, 一个
- C, P
- C, 一个, P
What are the primary phases of a Reducer?
Q11.- 结合, 地图, and reduce
- shuffle, 种类, and reduce
- reduce, 种类, and combine
- 地图, 种类, and combine
To set up Hadoop workflow with synchronization of data between jobs that process tasks both on disk and in memory, 使用 ___
服务, 这是 ___
.
Q12. - Oozie; 开源
- Oozie; commercial software
- Zookeeper; commercial software
- Zookeeper; 开源
For high availability, which type of multiple nodes should you use?
Q13.- 数据
- 名称
- 记忆
- worker
DataNode supports which type of drives?
Q14.- hot swappable
- cold swappable
- warm swappable
- non-swappable
Which method is used to implement Spark jobs?
Q15.- on disk of all workers
- on disk of the master node
- in memory of the master node
- in memory of all workers
In a MapReduce job, where does the map() function run?
Q16.- on the reducer nodes of the cluster
- on the data nodes of the cluster (NOT SURE)
- on the master node of the cluster
- on every node of the cluster
To reference a master file for lookups during Mapping, what type of cache should be used?
Q17.- distributed cache
- local cache
- partitioned cache
- cluster cache
Skip bad records provides an option where a certain set of bad input records can be skipped when processing what type of data?
Q18.- cache inputs
- reducer inputs
- intermediate values
- map inputs
Which command imports data to Hadoop from a MySQL database?
Q19.- spark import –connect jdbc:mysql://mysql.example.com/spark –username spark –warehouse-dir user/hue/oozie/deployments/spark
- sqoop import –connect jdbc:mysql://mysql.example.com/sqoop –username sqoop –warehouse-dir user/hue/oozie/deployments/sqoop
- sqoop import –connect jdbc:mysql://mysql.example.com/sqoop –username sqoop –password sqoop –warehouse-dir user/hue/oozie/deployments/sqoop
- spark import –connect jdbc:mysql://mysql.example.com/spark –username spark –password spark –warehouse-dir user/hue/oozie/deployments/spark
In what form is Reducer output presented?
Q20.- compressed (NOT SURE)
- sorted
- not sorted
- encrypted
Which library should be used to unit test MapReduce code?
Q21.- JUnit
- XUnit
- MRUnit
- HadoopUnit
If you started the NameNode, then which kind of user must you be?
Q22.- hadoop-user
- super-user
- node-user
- admin-user
State _ between the JVMs in a MapReduce job
Q23.- can be configured to be shared
- is partially shared
- is shared
- is not shared (https://www.lynda.com/Hadoop-tutorials/Understanding-Java-virtual-machines-JVMs/191942/369545-4.html)
To create a MapReduce job, what should be coded first?
Q24.- a static job() 方法
- a Job class and instance (NOT SURE)
- a job() 方法
- a static Job class
To connect Hadoop to AWS S3, which client should you use?
Q25.- S3A
- S3N
- S3
- the EMR S3
HBase works with which type of schema enforcement?
Q26.- schema on write
- no schema
- external schema
- schema on read
HDFS files are of what type?
Q27.- read-write
- read-only
- write-only
- append-only
A distributed cache file path can originate from what location?
Q28.- hdfs or top
- HTTP
- hdfs or http
- hdfs
Which library should you use to perform ETL-type MapReduce jobs?
Q29.- 蜂巢
- Pig
- Impala
- Mahout
What is the output of the Reducer?
Q30.- a relational table
- an update to the input file
- 一个, combined list
- a set of <钥匙, 值> 对
map function processes a certain key-value pair and emits a certain number of key-value pairs and the Reduce function processes values grouped by the same key and emits another set of key-value pairs as output.
To optimize a Mapper, what should you perform first?
Q31.- Override the default Partitioner.
- Skip bad records.
- Break up Mappers that do more than one task into multiple Mappers.
- Combine Mappers that do one task into large Mappers.
When implemented on a public cloud, with what does Hadoop processing interact?
Q32.- files in object storage
- graph data in graph databases
- relational data in managed RDBMS systems
- JSON data in NoSQL databases
In the Hadoop system, what administrative mode is used for maintenance?
Q33.- data mode
- safe mode
- single-user mode
- pseudo-distributed mode
In what format does RecordWriter write an output file?
Q34.- <钥匙, 值> 对
- 钥匙
- 值
- <值, 钥匙> 对
To what does the Mapper map input key/value pairs?
Q35.- an average of keys for values
- a sum of keys for values
- a set of intermediate key/value pairs
- a set of final key/value pairs
Which Hive query returns the first 1,000 值?
Q36.- SELECT…WHERE value = 1000
- SELECT … LIMIT 1000
- SELECT TOP 1000 ...
- SELECT MAX 1000…
To implement high availability, how many instances of the master node should you configure?
Q37.- 一
- zero
- 共享
- two or more (https://data-flair.training/blogs/hadoop-high-availability-tutorial)
Hadoop 2.x and later implement which service as the resource coordinator?
Q38.- 州长
- JobManager
- JobTracker
- YARN
In MapReduce, _ have _
Q39.- 任务; 工作
- 工作; 活动
- 工作; 任务
- 活动; 任务
What type of software is Hadoop Common?
Q40.- 数据库
- distributed computing framework
- 操作系统
- productivity tool
If no reduction is desired, you should set the numbers of _ tasks to zero.
Q41.- combiner
- reduce
- mapper
- 中间
MapReduce applications use which of these classes to report their statistics?
Q42.- mapper
- reducer
- combiner
- counter
_ is the query language, and _ is storage for NoSQL on Hadoop.
Q43.- 高密度文件系统; HQL
- HQL; HBase
- 高密度文件系统; 查询语句
- 查询语句; HBase
MapReduce 1.0 _ YARN.
Q44.- does not include
- is the same thing as
- 包括
- replaces
Which type of Hadoop node executes file system namespace operations like opening, closing, and renaming files and directories?
Q45.- ControllerNode
- DataNode
- MetadataNode
- NameNode
HQL queries produce which job types?
Q46.- Impala
- MapReduce
- 火花
- Pig
Suppose you are trying to finish a Pig script that converts text in the input string to uppercase. What code is needed on line 2 下面?
Q47.1 data = LOAD ‘/user/hue/pig/examples/data/midsummer.txt’… 2
- 如 (文本:CHAR[]); upper_case = FOREACH data GENERATE org.apache.pig.piggybank.evaluation.string.UPPER(文本);
- 如 (文本:CHARARRAY); upper_case = FOREACH data GENERATE org.apache.pig.piggybank.evaluation.string.UPPER(文本);
- 如 (文本:CHAR[]); upper_case = FOREACH data org.apache.pig.piggybank.evaluation.string.UPPER(文本);
- 如 (文本:CHARARRAY); upper_case = FOREACH data org.apache.pig.piggybank.evaluation.string.UPPER(文本);
In a MapReduce job, which phase runs after the Map phase completes?
Q48.- Combiner
- Reducer
- Map2
- Shuffle and Sort
Where would you configure the size of a block in a Hadoop environment?
Q49.- dfs.block.size in hdfs-site.xmls
- orc.write.variable.length.blocks in hive-default.xml
- mapreduce.job.ubertask.maxbytes in mapred-site.xml
- hdfs.block.size in hdfs-site.xml
Hadoop systems are _ RDBMS systems.
辅酶50.- replacements for
- not used with
- substitutes for
- additions for
Which object can be used to distribute jars or libraries for use in MapReduce tasks?
Q51.- distributed cache
- library manager
- lookup store
- registry
To view the execution details of an Impala query plan, which function would you use?
Q52.- explain
- query action
- detail
- query plan
Which feature is used to roll back a corrupted HDFS instance to a previously known good point in time?
Q53.- partitioning
- 快照
- 复制
- 高可用性
Hadoop Common is written in which language?
Q54.- C ++
- C
- Haskell
- Java的
Which file system does Hadoop use for storage?
Q55.- NAS
- FAT
- 高密度文件系统
- NFS
What kind of storage and processing does Hadoop support?
Q56.- encrypted
- verified
- 分散式
- remote
Hadoop Common consists of which components?
Q57.- Spark and YARN
- HDFS and MapReduce
- HDFS and S3
- Spark and MapReduce
Most Apache Hadoop committers’ work is done at which commercial company?
Q58.- Cloudera
- 微软
- 谷歌
- 亚马逊
To get information about Reducer job runs, which object should be added?
Q59.- Reporter
- IntReadable
- IntWritable
- 作家
After changing the default block size and restarting the cluster, to which data does the new size apply?
Q60.- all data
- no data
- existing data
- new data
Which statement should you add to improve the performance of the following query?
Q61.SELECT
c.id,
c.name,
c.email_preferences.categories.surveys
FROM customers c;
- 通过...分组
- 筛选
- SUB-SELECT
- SORT
What custom object should you implement to reduce IO in MapReduce?
Q62.- Comparator
- Mapper
- Combiner
- Reducer
You can optimize Hive queries using which method?
Q63.- secondary indices
- summary statistics
- column-based statistics
- a primary key index
If you are processing a single action on each input, what type of job should you create?
Q64.- partition-only
- map-only
- reduce-only
- combine-only
The simplest possible MapReduce job optimization is to perform which of these actions?
Q65.- Add more master nodes.
- Implement optimized InputSplits.
- Add more DataNodes.
- Implement a custom Mapper.
When you implement a custom Writable, you must also define which of these object?
Q66.- a sort policy
- a combiner policy
- a compression policy
- a filter policy
To copy a file into the Hadoop file system, what command should you use?
Q67.- hadoop fs -copy
- hadoop fs -copy
- hadoop fs -copyFromLocal
- hadoop fs -copyFromLocal
Delete a Hive _ table and you will delete the table _.
Q68.- managed; metadata
- external; data and metadata
- external; metadata
- managed; 数据
To see how Hive executed a JOIN operation, use the _ statement and look for the _ value.
Q69.- EXPLAIN; JOIN Operator
- QUERY; MAP JOIN Operator
- EXPLAIN; MAP JOIN Operator
- QUERY; JOIN Operator
Pig operates in mainly how many nodes?
Q70.- 二
- 三
- 四
- Five
After loading data, _ and then run a(n) _ query for interactive queries.
Q71.- invalidate metadata; Impala
- validate metadata; Impala
- invalidate metadata; 蜂巢
- validate metadata; 蜂巢
In Hadoop MapReduce job code, what must be static?
Q72.- 配置
- Mapper and Reducer
- Mapper
- Reducer
In Hadoop simple mode, which object determines the identity of a client process?
Q73.- Kerberos ticket
- kubernetes token
- guest operating system
- host operating system
Which is not a valid input format for a MapReduce job?
Q74.- FileReader
- CompositeInputFormat
- RecordReader
- TextInputFormat
If you see org.apache.hadoop.mapred, which version of MapReduce are you working with?
Q75.- 1.X
- 0.X
- 2.X
- 3.X
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