/ 
AC-Yenta-1
River stage zero No dependents
/ AC::Yenta

NAME

AC::Yenta - eventually-consistent distributed key/value data store. et al.

SYNOPSIS

use AC::Yenta::D;
use strict;

my $y = AC::Yenta::D->new( );

$y->daemon( $configfile, {
  argv		=> \@ARGV,
  foreground	=> $OPT{f},
  debugall		=> $OPT{d},
  port		=> $OPT{p},
} );

exit;

USAGE

Copy + Paste from the example code into your own code.
Copy + Paste from the example config into your own config.
Send in bug report.

YIDDISH-ENGLISH GLOSSARY

Kibitz - Gossip. Casual information exchange with ones peers.

Yenta - 1. An old woman who kibitzes with other yentas.
	2. Software which kibitzes with other yentas.

DESCRIPTION

Peers

All of the running yentas are peers. There is no master server. New nodes can be added or removed on the fly with no configuration.

Kibitzing

Each yenta kibitzes (gossips) with the other yentas in the network to exchange status information, distribute key-value data, and detect and correct inconsistent data.

Eventual Consistency

Key-value data is versioned with timestamps. By default, newest wins. Maps can be configured to keep and return multiple versions and client code can use other conflict resolution mechanisms.

Lost, missing or otherwise inconsistent data is detected by kibitzing merkle tree hash values.

Topological awareness

Yentas can take network topology into account when tranferring data around to minimize long-distance transfers. You will need to write a custom MySelf class with a my_datacenter function.

Multiple Network Interfaces / NAT

Yentas can take advantage of multiple network interfaces with different IP addresses (eg. a private internal network + a public network), or multiple addresses (eg. a private addresses and a public address) and various NAT configurations.

You will need to write a custom MySelf class and my_network_info function.

Network Information

By default, yentas obtain their primary IP address by calling gethostbyname( hostname() ). If this either does not work on your systems, or isn't the value you want to use, you will need to write a custom MySelf class and my_network_info function.

CONFIG FILE

various parameters need to be specified in a config file. if you modify the file, it will be reloaded automagically.

port

specify the TCP port to use

port 3503
environment

specify the environment or realm to run in, so you can run multiple independent yenta networks, such as production, staging, and dev.

environment prod
allow

specify networks allowed to connect.

allow 127.0.0.1
allow 192.168.10.0/24
seedpeer

specify initial peers to contact when starting. the author generally specifies 2 on the east coast, and 2 on the west coast.

seedpeer 192.168.10.11:3503
seedpeer 192.168.10.12:3503
secret

specify a secret key used to encrypt data transfered between yentas in different datacenters.

secret squeamish-ossifrage
syslog

specify a syslog facility for log messages.

syslog local5
debug

enable debugging for a particular section

debug map
map

configure a map (a collection of key-value data). you do not need to configure the same set of maps on all servers. maps should be configured similarly on all servers that they are on.

    map users {
	backend	    bdb
        dbfile      /home/acdata/users.ydb
        history     4
    }

BUGS

Too many to list here.

SEE ALSO

AC::Yenta::Client

Amazon Dynamo - http://www.allthingsdistributed.com/2007/10/amazons_dynamo.html

AUTHOR

Jeff Weisberg - http://www.solvemedia.com/