Looky Installation Routing
 | Table Of Content | |
1 Setup Server / Apache Server
You must be root or have permissions to create setup a WEB server to
proceed the steps described in this section.
- Assume that you have an Apache WEB server. If not, you must
adopt this document to the configuration of your WEB server.
- Assume that WWW:WWW is the user and the group of the
user running your WEB server.
- Assume that $DOWNLOAD names the directory where you have
downloaded the package files.
- Create directory /opt/looky and make this directory
readable and writeable to your Apache server:
#> cd /opt
#> mkdir looky
#> chown WWW:WWW looky
#> chmod 755 looky
- Copy files urload.pl and urload.pbp to this
directory /opt/looky
#> cd /opt
#> cp $DOWNLOAD/urload.pl looky
#> cp $DOWNLOAD/urload.pbp looky
#> chmod 755 looky/urload.pl
#> chmod 644 looky/urload.pbp
#> chown -R WWW:WWW looky
- Edit shebang of file /opt/looky/urload.pl to match
your local perl:
#> cd /opt
#> type perl
perl is /usr/bin/perl
#> vi looky/urload.pl
(ESC-i)#!/usr/bin/perl(ESC-wq)
- Add a script alias entry to your httpd.conf file.
ScriptAlias /looky/ /opt/looky/
- Restart your Apache server.
2 Install packages
The looky project uses a package installer called 'pkg-by-pkg'. This
package isntaller provides a platform independant way in installing
WEB based perl applications.
A pkg-by-pkg installation consists of two general steps:
- step 1: urloading
- step 2: install application
Within the urload phase, the package installer is installed by
itself: this is done by a stand-alone perl script named
urload.pl. This scripts takes a pkg-by-pkg file that
provides the pkg-by-pkg software.
Once this pkg-by-pkg software is installed, you get an admin
interface to maintain your looky installation. By default, your
looky installation consist only of infrastructure as provided by the
urload process. So you have to upload a looky core package
(looky-1.0.7-core.pbp) to your site first.
Once this is uploaded, the package must be 'imported'. During
import the pkg-by-pkg installer creates necessary subdirectories and
installs perl libaries and applications. After this is done the
looky installation must be configured and is ready for use.
If a new looky release has been posted, you could 'install' the next
release package files. The pkg-by-pkg installer replaces necessary
files but site dependant files (e.g. your configuration file) are
unchanged during this process.
The looky project provides three packages:
- looky-1.0.7-core.pbp: the looky core:
libaries and applications to run looky.
- looky-1.0.7-doc.pbp: this documentation.
- looky-1.0.7-rc.pbp: a set of rc scripts (to
make looky bootable) and application looky-killer.pl (to shut
down looky server)
If the pkg-by-pkg software has been changed, an other package
(looky-1.0.7-pkg.pbp) is shiped in a looky
release. This package is needed to update the infrastructure as
created by urload process of your looky installation. The package is
only needed if you already have a looky installation.
This sounds rather complex, but actually it is quite easy. The
installation routing is demonstrated in the following two sections.
2.1 Urload
- To run the urload process, use a web browser with URL
http://<server>/looky/urload.pl
to urload pkg-by-pkg structure to directory /opt/looky. If
you set up your Apache server als described in previous section, the
urload start screen is [shown].
On this screen two substeps steps are shown:
First some very basic checks are done: - The urload.pbp file
is checked, if this file exists and if it is readable or not. The
file has to be readable.
- The installation directory is checked
if an pkg-by-pkg instances already exists. Warning: you should not
install a pkg-by-pkg instance on an other instance: this is done at
your own risk!
If this checks are passed successfully the urloader tries to guess
the binary path to your perl interpreter and the root directory
where looky has to be installed (/opt/looky).
Please check the values quite carefully. This cannot be changed
later, so you must enter the correct values (In case you fail here:
just delete the complete directory root directory
/opt/looky and start again)
- On the next [screen], the given values for root-directory and
perl interpreter are checked. If this is ok, the package file
urload.pbp is opened and content is shown to you.
Just click 'accept' button to proceed.
- Now the pkg-by-pkg infrastructure is created. The result of
this step is shown on the next [screen].
Once the pkg-by-pkg infrastructure is available, the urload.pl
script tries to use the perl packages as urloaded from urload.pbp
file. If this fails, a perl error message is shown.
- On the next [screen], the package requirements are
checked. This phase may lead to a perl error that is shown to you:
in this case you have to fetch listed package from cpan.
- Finally, on the last [screen], the files urload.pl and
urload.php are deleted .
Instead of these a new file admin.pl has been created to
manage your looky installation. Just select [continue].
The urload is finshed by this screen. Now you should add looky
packages to this installation. This is described in next section.
2.2 Install Looky Core
- The admin script provides the following main [screen].
To upload the looky core package file, select [upload package]
- Select the looky-1.0.7-core.pbp file and
upload file by button [upload].
- The file is uploaded (this may take a while). If the upload
was successfully a positve result is [shown].
Select [import] to
jump to the import page.
- All uploaded files are [shown] to the user.
Just select [import]
of the uploaded looky-1.0.7-core.pbp file to start
import of the uploaded package.
- The package is extracted and its content is [shown] to the user.
Just select [import]
to import the package.
- The package is installed and the result of this process is [shown] to the user.
Just select [continue]
to proceed
- The imported package has added two links to the admin.pl
[script].
The installation process is done.
3 Configuration
Finally you have to setup the configuration. There are 4 things to
be done:
- define pools
- assign resource to pools
- setup security and finally
- setup redirection urls.
3.1 Define Pools
The definition of pools is a fundamental work. In general you have
to answer a simple question: it is necessary from organzational,
monentary or technical reasons to split you consumers into several
groups?
The answer to this question provides you the number of pools you
should define: for each group one pool. However one pool has to be
defined ... :-)
The next question is a little bit more complex: you have to assign a
usefull seed method, a latency time and a distribution mode. The
answer depends on your application.
| Goal |
Settings |
|
You just want to distribute your consumers to the resource with
a constant factor: e.g. 100:100:50
|
Use distribution mode '(auto-)queue'. Set seed method to
weighted or parallel. Set latency time to a short value.
|
|
You want to garantee that not more sessions are started than
provided on resource.
|
Use distribution mode 'sticky'. Set a very high latency time
(e.g. 200 days). Set any seed method you like. Use the
looky-sessioner.pl script to controll number of sessions.
|
|
You want to do control distribution by resource load.
|
Use distribution mode 'sticky'. Set a very high latency time
(e.g. 200 days). Set any seed method you like. Define opt and
max load values for each resource. Use the looky-controller.pl
server to master the looky-sever. Define a high optimal and
maximal 'have' value. Use the looky-probe client to collect
load from system.
|
3.2 Define Resources
Next step is to assign resources to the pools. This is quite easy:
just assign the number of sessions you want to run on this resources
as 'have' value of the resource.
Think if you have the need to have a resource located in more than
one pool. If this is true, think if this resource is shared or
coupled.
3.3 Setup Security
This is quite easy: If you run the looky server on the same server
than the apache hosting the LBC, the default ACL to access the looky
server is ok.
If you plan to run the looky server on an other host than the LBC's,
you should add this host to the 'allow' list in looky configuration.
If you use looky-sessioner clients, you have to modify the ACLs of
the looky server to grant access for the servers hosting the looky
sessioner clients. If you use looky probe clients, you have to do
the same for the ACL of the looky controller.
3.4 Setup Redirection
3.4.1 Setup up error redirection
However this is quite easy: Create three HTML files on the same WEB
server hosting the LBC: one file to signal to the consumer, that no
further resource exist (no-resource.html), one file to signal to the
consumer, that the looky server is offline (no-server.html) and one
file to signal to the consumer that he had entered an invalid url
(invalid-url.html)
3.4.2 Setup up standard redirection
This is the last step of the procedure. To speed up the
loadbalancing stuff, it is highly recommended to run the LBC by
mod_perl.
PerlModule Apache::Registry
# ----- map location 'load' to be run by LBC
#
ScriptAliasMatch ^/load/.* /opt/looky/looky-client-cgi.pl
# ----- host this location by mod_perl
#
<Location /load/>
SetHandler perl-script
PerlHandler Apache::Registry
Options +ExecCGI
PerlSendHeader On
allow from all
</Location>
Once this is done, the following is recommended for redirection.
http://<server>/load/<pool>/<start>/<url>/<of>?<your>=<application>
`----´ `----------------´ `------------------´
| | |
get pool from this segment make path transient |
from segment 2 |
just use query part
as given by url
If pools are set, compute the pool from the following segment (here
segment '1'). Copy the rest of the path as transient value to
redirection URL. Pass query part unchanged.
As a result from this, you get the following configuration:
redirect:http://%{resource}/%{path}%{url/query:?%{url/query}}%{url/fragment:#%{url/fragment}}
compute.pool:path/1
transient.path:2
4 Start processes
This step is quite easy: Just start the looky server like this:
$>cd /opt/looky
$>perl looky-server.pl -q &
If you have installed the looky-1.0.7-rc.pbp
package you may start the looky server by this script.
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install