README

Eddie (1.5.0).
~~~~~~~~~~~~~~

1) What is this?

This high availability software package includes the components of 
Eddie, the IP Migration Application, the Intelligent HTTP Gateway 
and the Load Balancing DNS Package.

It is only meaningful to install Eddie on a *set* of
hosts. Never the less it is possible to simulate advanced clusters on
a single host. Read the tutorial included in this package to do this.

This is a beta release but we intend to remove the beta label within
the year and to release an NT version as soon as possible.

The other Eddie component are the Load-balancing DNS Server and the
Content Replication Application (experimental). They can be found at
http://www.eddieware.org/ and can either be used separately or
together.

The IP Migration Application is an all-purpose cluster solution making
it possible to setup overlapping take-over and fail-over sets using
any type of servers. The goal is to be in service as long as at least
one host is running. All aspects of the clustering are configurable
and call-back scripts can be written to customize start, stop,
monitoring and alarm handling. Our goal is to compete with products
such as Microsoft's Cluster Server etc.

The Intelligent HTTP Gateway is a peer which sits on top of back-end
HTTP servers such as the Apache Web server. The gateway schedules
requests to the least loaded back-ends on the LAN using adaptable
load-balancing algorithms. It also analyzes incoming requests
directing certain types of traffic to certain types of hosts using
configurable scheduling patterns, e.g. CGI-script requests can be
directed to host A and requests for static HTML pages to host B.

The gateway also features advanced admission control mechanisms, it
handles a session for each client and during server overload only
clients with active sessions are granted access. A new client is put
on hold (queued) during overload but is given a queue number and a
rough estimate on when access is granted. The client is frequently and
automatically reconnected as he/she advances in the queue. This
behavior is fully configurable, e.g. customized put on hold HTML pages
and CGI-scripts can be specified (commercials?). 

If the Load-balancing DNS Server, or indeed a simple round-robin DNS
server, and the IP Migration Application are used together several
gateways can be used in parallel. This guarantees a solution with high
throughput, high availability and a high degree of scalability. A
single host can even harbor several gateways and back-ends at the same
time if necessary. The gateways take this into account and the
load-balancing algorithms adapt.

2)  Compilation & Installation

Read INSTALL.

3) Configuration
 
Read $EDDIE_ROOT/doc/tutorial.ps.

4) Documentation summary

The amount of documentation included in this package is unfortunately
quite meager. We have focused on functionality rather than on a
talkative User's Guide.

We describe five example configurations harmonizing with the
configuration example in the DNS server package. 

README
	This file.
INSTALL
	Installation instructions.
LICENSE
	Erlang Public License, a modified Mozilla Public License.
RELEASE_NOTES
	Please read these as some documentation maybe out of date.

For more documentation please visit the web site:
    http://www.eddieware.org/documentation.html

5) Open source release.

This is an open source release - it comes with no guarantees
(and the usual disclaimers). It is has some problems (like 
brittle configuration scripts; it's not thoroughly auditted 
for security problems, etc).

6) Support.

If you have problems report this to team@eddieware.org.
The web site contains a bug reporting system.
    http://www.eddieware.org/support.html