1. What is Logstash?

A) It is an open-source data processing tool
B) It is an automated testing tool
C) It is a database management system
D) It is a data visualization tool

Answer: A)

2. Which programming language is used to write Logstash plugins?

A) Java
B) Python
C) Ruby
D) All of the above

Answer: C)

3. What is the purpose of Logstash grok filter?

A) To convert logs into JSON format
B) To parse unstructured log data
C) To compress log data
D) To encrypt log data

Answer: B)

4. Which of the following is NOT a Logstash filter plugin?

A) Grok
B) Mutate
C) Date
D) Java

Answer: D)

5. Which output plugin should be used to store logs in Elasticsearch?

A) Filebeat
B) Kafka
C) Redis
D) Elasticsearch

Answer: D)

6. How can you add the timestamp to log messages in Logstash?

A) By using the Date filter plugin
B) By using the Elasticsearch output plugin
C) By using the File input plugin
D) By using the Grok filter plugin

Answer: A)

7. What is the purpose of the Logstash split filter?

A) To split log messages into multiple sections
B) To split unstructured data into fields
C) To split data into different output streams
D) To split data across multiple Logstash instances

Answer: A)

8. Which plugin would you use to remove fields from a log message?

A) Grok
B) Mutate
C) Date
D) Elasticsearch

Answer: B)

9. What is the purpose of the Logstash aggregate filter?

A) To summarize log data into a single message
B) To aggregate logs from multiple sources
C) To filter out unwanted data from logs
D) None of the above

Answer: A)

10. How can you ensure that Logstash processes messages in order?

A) By using the input plugin
B) By using the output plugin
C) By using the filter plugin
D) By using the codec plugin

Answer: C)

11. Which plugin would you use to convert a log message into JSON format?

A) Grok
B) Json
C) Date
D) Elasticsearch

Answer: B)

12. What is the purpose of the multiline filter in Logstash?

A) To combine multiple log messages into a single event
B) To split log messages into multiple events
C) To convert log data to a JSON format
D) To remove unwanted fields from log messages

Answer: A)

13. Which plugin should be used to ingest data from a CSV file?

A) Csv
B) File
C) Json
D) Grok

Answer: A)

14. What is the purpose of the Logstash fingerprint filter?

A) To compress log data
B) To generate unique identifiers for log messages
C) To tokenize log data
D) To extract fields from log messages

Answer: B)

15. Which codec should be used to read syslog messages?

A) Json
B) Syslog
C) Plain
D) None of the above

Answer: B)

16. How can you add a prefix to log messages in Logstash?

A) By using the mutate filter plugin
B) By using the date filter plugin
C) By using the File input plugin
D) By using the Elasticsearch output plugin

Answer: A)

17. What is the purpose of the Logstash translate filter?

A) To translate log messages into different languages
B) To convert log data into CSV format
C) To convert timestamps to a specified format
D) To replace values in log messages

Answer: D)

18. Which plugin would you use to convert a log message to uppercase?

A) Json
B) Uppercase
C) Grok
D) Mutate

Answer: D)

19. What is the purpose of the kv filter in Logstash?

A) To convert log messages into key-value pairs
B) To aggregate log data from multiple sources
C) To split log messages into multiple events
D) None of the above

Answer: A)

20. Which codec should be used to read JSON data?

A) Json_lines
B) Plain
C) Csv
D) Syslog

Answer: A)

21. What is the purpose of the Logstash throttle filter?

A) To control the rate at which log messages are processed
B) To aggregate log data from multiple sources
C) To split log messages into multiple events
D) None of the above

Answer: A)

22. Which plugin would you use to add a new field to a log message?

A) Mutate
B) Date
C) Json
D) Syslog

Answer: A)

23. What is the purpose of the Logstash uri_parser filter?

A) To parse URIs in log messages
B) To split log messages into multiple events
C) To convert timestamps to a specified format
D) None of the above

Answer: A)

24. Which plugin should be used to ingest data from Kafka?

A) Kafka
B) File
C) Csv
D) Grok

Answer: A)

25. What is the purpose of the Logstash syslog_pri filter?

A) To parse syslog messages
B) To split log messages into multiple events
C) To convert timestamps to a specified format
D) None of the above

Answer: A)

26. Which codec should be used to read Avro data?

A) Avro
B) Csv
C) Syslog
D) Plain

Answer: A)

27. What is the purpose of the Logstash bytes filter?

A) To convert log data to bytes format
B) To split log messages into multiple events
C) To convert timestamps to a specified format
D) To limit the size of log messages

Answer: D)

28. Which plugin would you use to add a tag to a log message?

A) Json
B) Mutate
C) Grok
D) Csv

Answer: B)

29. What is the purpose of the Logstash drop filter?

A) To drop log messages that match a specified condition
B) To aggregate log data from multiple sources
C) To split log messages into multiple events
D) None of the above

Answer: A)

30. Which plugin should be used to ingest data from a SQL database?

A) Jdbc
B) File
C) Csv
D) Grok

Answer: A)

31. What is the purpose of the Logstash dns filter?

A) To resolve IP addresses to hostnames in log messages
B) To split log messages into multiple events
C) To convert timestamps to a specified format
D) None of the above

Answer: A)

32. Which codec should be used to read XML data?

A) Xml
B) Csv
C) Json
D) Syslog

Answer: A)

33. What is the purpose of the Logstash prune filter?

A) To remove fields from log messages that match a specified condition
B) To split log messages into multiple events
C) To convert timestamps to a specified format
D) None of the above

Answer: A)

34. Which plugin would you use to perform a DNS lookup in Logstash?

A) Json
B) Dns
C) Csv
D) Grok

Answer: B)

35. What is the purpose of the Logstash uuid filter?

A) To generate a unique identifier for each log message
B) To split log messages into multiple events
C) To convert timestamps to a specified format
D) None of the above

Answer: A)

36. Which codec should be used to read YAML data?

A) YAML
B) Json
C) Syslog
D) Csv

Answer: A)

37. What is the purpose of the Logstash geoip filter?

A) To add geo-location information to log messages
B) To split log messages into multiple events
C) To convert timestamps to a specified format
D) None of the above

Answer: A)

38. Which plugin should be used to ingest data from a MongoDB database?

A) Mongo
B) File
C) Csv
D) Grok

Answer: A)

39. What is the purpose of the Logstash throttle_retry filter?

A) To retry log messages when a specified condition is met
B) To aggregate log data from multiple sources
C) To split log messages into multiple events
D) None of the above

Answer: A)

40. Which codec should be used to read JSON logs with multiple lines?

A) Json_lines
B) Json
C) Csv
D) Plain

Answer: A)

41. What is the purpose of the Logstash clone filter?

A) To create a copy of a log message
B) To split log messages into multiple events
C) To convert timestamps to a specified format
D) None of the above

Answer: A)

42. Which plugin would you use to remove leading and trailing white spaces from a log message?

A) Grok
B) Strip
C) Csv
D) Json

Answer: B)

43. What is the purpose of the Logstash mutate_replace filter?

A) To replace field values in log messages
B) To aggregate log data from multiple sources
C) To split log messages into multiple events
D) None of the above

Answer: A)

44. Which codec should be used to read Apache Avro logs?

A) Avro
B) Csv
C) Json
D) Plain

Answer: A)

45. What is the purpose of the Logstash cidr filter?

A) To match IP addresses in log messages against a CIDR block
B) To split log messages into multiple events
C) To convert timestamps to a specified format
D) None of the above

Answer: A)

46. Which plugin would you use to rename a field in a log message?

A) Mutate_rename
B) Grok
C) Csv
D) Json

Answer: A)

47. What is the purpose of the Logstash xml filter?

A) To parse XML data from log messages
B) To split log messages into multiple events
C) To convert timestamps to a specified format
D) None of the above

Answer: A)

48. Which codec should be used to read Apache Kafka logs?

A) Kafka
B) Json
C) Csv
D) Syslog

Answer: A)

49. What is the purpose of the prune_metadata filter in Logstash?

A) To remove metadata fields from log messages
B) To aggregate log data from multiple sources
C) To split log messages into multiple events
D) None of the above

Answer: A)

50. Which plugin should be used to ingest data from a Couchbase database?

A) Couchbase
B) File
C) Csv
D) Grok

Answer: A)

The post Top 50 Logstash Interview Questions with Answers appeared first on scmGalaxy.

What is Logstash?
Logstash is an open source, server-side data processing pipeline that ingests data from a multitude of sources simultaneously, transforms it, and then sends it to your favorite “stash.”

Logstash Benefits

• Logstash allows you to easily ingest unstructured data from a variety of data sources including system logs, website logs, and application server logs.
• Logstash offers pre-built filters, so you can readily transform common data types, index them in Elasticsearch, and start querying without having to build custom data transformation pipelines.
• With over 200 plugins already available on Github, it is likely that someone has already built the plugin you need to customize your data pipeline.

Logstash work in 3 phases….

Phase 1 – When it comes from ingests data from a multitude of sources simultaneously, which includes files, s3,beats, kafka etc. Data is often scattered or siloed across many systems in many formats. Logstash supports a variety of inputs that pull in events from a multitude of common sources, all at the same time.
List of sources from where logstash can ingest the data are as follows;
https://www.elastic.co/guide/en/logstash/current/input-plugins.html

Phase 2 – Next, It Parse & Transform Your Data On the Fly. As data travels from source to store, Logstash filters parse each event, identify named fields to build structure, and transform them to converge on a common format for easier, accelerated analysis and business value. Logstash dynamically transforms and prepare your data regardless of format or complexity

Phase 3 – Last, Logstash stored the parsed data into Elasticsearch, aws,hadoop, Mongodb and go-to output that opens up a world of search and analytics possibilities.Logstash has a variety of outputs that let you route data where you want, giving you the flexibility to unlock a slew of downstream use cases. Some of these are given below;
https://www.elastic.co/guide/en/logstash/current/output-plugins.html

Where you can use the Logstash?

1. Log Analytics – Ingest un-structured and semi-structured logs generated by servers, applications, mobile devices, and more for a wide variety of applications such as digital marketing, application monitoring, fraud detection, ad tech, gaming, and IoT. Logstash provides plugins to quickly load data from a variety of data sources.
2. IT Operations Monitoring – Capture server logs and push them into your Elasticsearch cluster using Logstash. Elasticsearch indexes the data and makes it available for analysis in near real-time (less than one second). You can then use Kibana to visualize the data and perform operational analyses like identifying network issues and disk I/O problems. Your on-call teams can perform statistical aggregations to identify root cause and fix issues.

The post Logstash explained in 5 mins appeared first on scmGalaxy.