![The Family of Hadoop
Nham Xuan Nam
nhamxuannam [at] gmail.com
http://namnham.blogspot.com
Barcamp Saigon, December 13 2009](https://image.slidesharecdn.com/hadoop-091213113721-phpapp01/85/The-Family-of-Hadoop-1-320.jpg)
![WordCount Example
File01: File02:
Hello Barcamp Hello Everyone Hello Hadoop Hello Everyone
<_, Hello Barcamp Hello Everyone> <_, Hello Hadoop Hello Everyone>
<Hello, 2> <Hello, 2>
<Barcamp, 1> <Hadoop, 1>
<Everyone, 1> <Everyone, 1>
<Barcamp, [1]>
<Hadoop, [1]>
<Hello, [2,2]>
<Everyone, [1,1]>
<Barcamp, 1>
<Hadoop, 1>
<Hello, 4>
<Everyone, 2>](https://image.slidesharecdn.com/hadoop-091213113721-phpapp01/85/The-Family-of-Hadoop-19-320.jpg)
The Family of Hadoop
- 1. The Family of Hadoop Nham Xuan Nam nhamxuannam [at] gmail.com http://namnham.blogspot.com Barcamp Saigon, December 13 2009
- 2. Content History Sub-projects HDFS Map Reduce HBase Hive
- 3. History created by Doug Cutting, the creator of Lucene. Lucene: open source index & search library. Nutch: Lucene-based web crawler. Jun 2003, there was a successful 100 million page Nutch demo system. Nutch problem: its architecture could not scale to the billions of pages.
- 4. History Oct 2003, Google published the paper “The Google File System”. In 2004, Nutch team wrote an open source implementation of GFS, called Nutch Distributed File System (NDFS). Dec 2004, Google published the paper “MapReduce: Simplified Data Processing on Large Clusters”. In 2005, Nutch team implemented MapReduce in Nutch. Mid 2005, all the major Nutch algorithms had been ported to run using MapReduce and NDFS.
- 5. History Feb 2006, Nutch's NDFS and the MapReduce implementation formed Hadoop project. Doug Cutting joined Yahoo!. Jan 2008, Hadoop became Apache top-level project. Feb 2008, Yahoo! production search index was generated by a 10,000-core Hadoop cluster.
- 7. Sub-projects
- 9. Architecture
- 10. Data Model File stored as blocks (default size: 64M) Reliability through replication – Each block is replicated to several datanodes
- 11. Namenode & Datanodes Namenode (master) – manages the filesystem namespace – maintains the filesystem tree and metadata for all the files and directories in the tree. Datanodes (slaves) – store data in the local file system – Periodically report back to the namenode with lists of all existing blocks Clients communicate with both namenode and datanodes.
- 12. Data Flow
- 13. Data Flow
- 14. Accessibility FileSystem Java API – org.apache.hadoop.fs.* Web Interface Commands for HDFS users $ hadoop dfs mkdir /barcamp $ hadoop dfs ls /barcamp Commands for HDFS admins $ hadoop dfsadmin report $ hadoop dfsadmin refreshNodes
- 17. Programming Model Data is a stream of keys and values Map – Input: <key1,value1> pairs from data source – Output: immediate <key2,value2> pairs Reduce – Called once per a key, in sorted order Input: <key2, list of value2> Output: <key3,value3> pairs
- 18. Data Flow
- 19. WordCount Example File01: File02: Hello Barcamp Hello Everyone Hello Hadoop Hello Everyone <_, Hello Barcamp Hello Everyone> <_, Hello Hadoop Hello Everyone> <Hello, 2> <Hello, 2> <Barcamp, 1> <Hadoop, 1> <Everyone, 1> <Everyone, 1> <Barcamp, [1]> <Hadoop, [1]> <Hello, [2,2]> <Everyone, [1,1]> <Barcamp, 1> <Hadoop, 1> <Hello, 4> <Everyone, 2>
- 20. MapReduce in Hadoop JobTracker (master) – handling all jobs. – scheduling tasks on the slaves. – monitoring & re-executing tasks. TaskTrackers (slaves) – execute the tasks. Task – run an individual map or reduce.
- 23. Introduction Nov 2006, Google released the paper “Bigtable: A Distributed Storage System for Structured Data” BigTable: distributed, column-oriented store, built on top of Google File System. HBase: open source implementation of BigTable, built on top of HDFS.
- 24. Data Model Data are stored in tables of rows and columns. Cells are ”versioned” → Data are addressed by row/column/version key. Table rows are sorted by row key, the table's primary key. Columns are grouped into column families. → A column name has the form “<family>:<label>” Tables are stored in regions. Region: a row range [start-key : end-key)
- 25. Data Model
- 26. Architecture
- 27. Architecture Master Server – assigns regions to regionservers – monitors the health of regionservers – handles administrative funtions RegionServers – contain regions and handle client read/write requests Catalog Tables (ROOT and META) – maintain the current list, state, recent history, and location of all regions.
- 28. Accessibility Client API org.apache.hadoop.hbase .client.* HBase Shell $ bin/hbase shell hbase> Web Interface
- 30. Introduction started at Facebook an open source data warehousing solution built on top of Hadoop for managing and querying structured data Hive QL: SQL-like query language – compiled into map-reduce jobs log processing, data mining,...
- 31. Data Model Tables – analogous to tables in RDBMS – rows are organized into typed columns – all the data is stored in a directory in HDFS Partitions – determine the distribution of data within sub-directories of the table directory Buckets – based on the hash of a column in the table – Each bucket is stored as a file in the partition directory
- 32. Architecture
- 33. Architecture Metastore – contains metadata about data stored in Hive. – stored in any SQL backend or an embedded Derby. – Database: a namespace for tables – Table metadata: column types, physical layout,... – Partition metadata Compiler Excution Engine Shell
- 34. Hive Query Language Data Definition (DDL) statements – CREATE/DROP/ALTER TABLE – SHOW TABLE/PARTITIONS Data Manipulation (DML) statements – LOAD DATA – INSERT – SELECT User Defined functions: UDF/UDAF
- 35. Hive @ Facebook