> For the complete documentation index, see [llms.txt](https://bigdata-2.gitbook.io/bd201notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bigdata-2.gitbook.io/bd201notes/questions/questions-for-screanings/junior.md).

# junior

## Hadoop

* What task can be considered as BigData task?
* What is Hadoop?
* Pros & Cons of using Hadoop.
  * Pros: Scalable, Cost Effective, Flexible, Computing Power, Fault Tolerant 
  * Cons: Security Concern, Potential Stability Issues, Not Fit for Small Data
* Describe types of data in terms of structure. (Structured, Semi-Structured, Unstructured)
* Schema on read vs schema on write

## HDFS

* Name HDFS node types. (NameNode and DataNode) 
* What is the purpose of each of them?
* How HDFS achieves Fault Tolerance? (Data Replication)
* Block size. Physical space allocation of blocks.
* Small files problem. Small file problem solutions
* What is rack and rack awareness? Data locality.
* How does name node mange meta data fsimage; editlogs, SecondaryNameNode
* Describe at least one way to achieve High Availability. (StandBy NameNode, QJN, NFS, ZooKeeper etc.)
  * Active node
  * Standby node 
  * Journal Node
* What are differences between CheckpointingNameNode and BackupNameNode?
* File Formats. Describe and compare these file formats: ORC, Sequence; Avro; JSON

## Yarn

* What is Yarn?
* Types of schedulers (FIFO, Fair, Capacity) and how they work
* Describe the process of resource distribution during launching of disributed application: 

## DevOps

* Continuous integration, Continuous delivery, Continuous deployment what are the benefits of each?
* What is Infrastructure as a Code? \[max 1 point]
* Docker image; Docker container; Docker Hub.
* Describe these DevOps tools: 
  * Jenkins
  * Sonar
  * Puppet 
  * Chef
  * Ansible