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old repo was full of junk. Here's a nice clean new repo.

if there's interest in the project this will evolve into a full blown CPAN
module, or I'll rewrite it into C and ... not put it on CPAN.
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dormando committed Oct 13, 2009
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30 changes: 30 additions & 0 deletions LICENSE
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Copyright (c) 2009, Dormando
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.

* Neither the name of the Danga Interactive nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
82 changes: 82 additions & 0 deletions README
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Load balancer test cluster emulator
Copyright 2009 Dormando (dormando@rydia.net)

Pre-CPAN release of some quick test cluster software I wrote for a talk at
Velocity 2009.

Dependencies:

Danga::Socket (though future releases might switch to AnyEvent)

To start
========

$ ./lbemu examples/ideal-test.yaml
initialized "basic webserver" listener on 127.0.0.1:5000
initialized "basic webserver" listener on 127.0.0.1:5001
initialized "basic webserver" listener on 127.0.0.1:5002
initialized "basic webserver" listener on 127.0.0.1:5003
initialized "basic webserver" listener on 127.0.0.1:5004
initialized "basic webserver" listener on 127.0.0.1:5005
initialized "basic webserver" listener on 127.0.0.1:5006
initialized "basic webserver" listener on 127.0.0.1:5007
initialized "basic webserver" listener on 127.0.0.1:5008
initialized "basic webserver" listener on 127.0.0.1:5009

Look in examples/ directory for a few examples.

HTTP parsing is _ultra_ simple. It supports an 'OPTIONS *' command, and a GET
vs any configured URL's. No other processing is done. Responses consist of 'x'
characters up to the requested response length.

It's pretty fast. Disabling the scheduling algorithm I can get over 10,000
requests/sec on my laptop. With the algo it's a lot lower but still pretty
good. A big point with this software is not to push a huge volume of requests
through it, however.

What lbemu is
=============

lbemu is a no-frills web cluster emulator. It allows you to create fake
webservers listening on many IPs or ports, which you can then configure into
your load balancer or proxy. It is useful in tuning paramters on your load
balancer and for comparing effectiveness of different load balancers, if you
are evaluating hardware/software solutions.

Lbemu contains a fake even-balanced CPU scheduler in order to emulate how much
*time* it takes to process a request.

- Specify a machine as having 1-n CPU's (lets say four)
- Specify each CPU as being able to process n 'ticks' per second (lets say
5000)
- lbemu runs at 50 'frames' per second. This is tunable in the top of your
sourcecode if you frequently lag on a loop.
- Requests are specified as having 0 or more ticks. a 0 tick doesn't enter the
scheduler, it's immediately responded to. This is for requests like OPTIONS
or a small static file.
- lbemu attempts to have a request process in that amount of time, per
scheduled across the CPUs.

So if you have a request that takes 1000 ticks, with 4 cpus with a 5000 tick
capacity each, a single request against the server should complete in roughly
200 milliseconds.

If you issue 4 requests all at once, they should all return in roughly 200
milliseconds.

If you issue 8 requests all at once, they should all return in roughly 400
milliseconds. This is what sets lbemu aside as far as lightweight server
emulation goes; it's not simply taking a request and returning a response
after N amount of time. Based on the requests presently being processed,
finished, running in parallel, requests will fluctuate and slow down at least
somewhat similar to a real web cluster.

You can also specify the equivalent of an apache MaxClients, which allows you
to properly test perlbal or similar load balancer.

If you think this stuff is useful, have a patch or idea, or want to say
thanks or how much you hate me, feel free to shoot me an e-mail :) If there's
interest, or if I continue to use the software, I'll continue to make
releases.

- Dormando (dormando@rydia.net)
32 changes: 32 additions & 0 deletions examples/ideal-test.yaml
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# Web cluster with nothing wrong with it
requests:
normal:
name: "normal request"
url: "/normal"
ticks: 400
size: 5000
fast:
name: "immediate response"
url: "/fast"
ticks: 0
size: 500

servers:
basic:
name: "basic webserver"
cpu_count: 4
cpu_speed: 4000
max_conns: 8
listen_queue: 5
keep_alive: 1

clusters:
main:
name: "main cluster"
port_start: 5000
ip: "127.0.0.1"
total: 10
server_type: "basic"
requests:
- "normal"
- "fast"
48 changes: 48 additions & 0 deletions examples/swap-test.yaml
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# Cluster with one server who is swapping or otherwise impaired.
requests:
normal:
name: "normal request"
url: "/normal"
ticks: 400
size: 5000
fast:
name: "immediate response"
url: "/fast"
ticks: 0
size: 500

servers:
basic:
name: "basic webserver"
cpu_count: 4
cpu_speed: 4000
max_conns: 8
listen_queue: 5
keep_alive: 1
swapper:
name: "swapping webserver"
cpu_count: 4
cpu_speed: 500
max_conns: 8
listen_queue: 5
keep_alive: 1

clusters:
swap:
name: "swap cluster"
port_start: 5009
ip: "127.0.0.1"
total: 1
server_type: "swapper"
requests:
- "normal"
- "fast"
main:
name: "main cluster"
port_start: 5000
ip: "127.0.0.1"
total: 9
server_type: "basic"
requests:
- "normal"
- "fast"
48 changes: 48 additions & 0 deletions examples/uneven-test.yaml
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# Cluster where half of the servers are old, and half are new.
requests:
normal:
name: "normal request"
url: "/normal"
ticks: 400
size: 5000
fast:
name: "immediate response"
url: "/fast"
ticks: 0
size: 500

servers:
new:
name: "new webserver"
cpu_count: 4
cpu_speed: 4000
max_conns: 8
listen_queue: 5
keep_alive: 1
old:
name: "old webserver"
cpu_count: 4
cpu_speed: 2000
max_conns: 8
listen_queue: 5
keep_alive: 1

clusters:
new:
name: "new cluster"
port_start: 5000
ip: "127.0.0.1"
total: 5
server_type: "new"
requests:
- "normal"
- "fast"
old:
name: "old cluster"
port_start: 5005
ip: "127.0.0.1"
total: 5
server_type: "old"
requests:
- "normal"
- "fast"

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