TWiki - reference design for a scalable, structured wiki application

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Functional Overview

This application is fully featured, scalable, sturctured wiki, based on TWiki 4.0.2 (http://twiki.org/). The scalable infrastructure is built using AppLogic and AppLogic's catalog appliances.

TWiki is a flexible, powerful, and easy to use enterprise collaboration platform and knowledge management system. It is a Structured Wiki, typically used to run a project development space, a document management system, a knowledge base, or any other groupware tool, on an intranet or on the internet. Web content can be created collaboratively by using just a browser.

For administration and user guides please see the TWiki website or follow the links below: http://twiki.org/cgi-bin/view/TWiki04/TWikiUsersGuide http://twiki.org/cgi-bin/view/TWiki04/TWikiReferenceManual http://twiki.org/cgi-bin/view/TWiki04/TWikiReleaseNotes04x00x00

The TWiki application is packaged as an appliance. All required configuration is exposed on the boundary of the application, so that the application can be configured as a single appliance (using the Application Configuration property sheet in the editor).

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Boundary

Properties

These are the only settings that you must configure in order to start the application. Note that certain settings are automatically distributed to multiple appliances (such as the DNS servers, the admin e-mail, etc.). You don't need to understand the internal structure of the application in order to be able to configure it.

Property Name	Type	Description
usr_ip	IP	This is the IP address at which the application provides services to users. This property is mandatory
mail_ip	IP	This is the IP address that the mail gateway is going to use to send e-mail from. This property is mandatory. In the future, we may provide auto assignment of IP addresses to output gateways.
netmask	IP	Netmask for the network on which usr_ip and mail_ip reside. Default: 255.255.255.0
gateway	IP	Address of IP gateway to be used to route traffic. This property must be specified in order to access the TWiki application from hosts outside of the IP network on which TWiki is running (i.e., most cases). Use 0.0.0.0 to disable. This property is mandatory.
dns1	IP	IP address of a DNS server for host name resolutions. Used to resolve the mail server name. Default: 0.0.0.0
dns2	IP	IP address of a backup DNS server for host name resolutions. Used to resolve the mail server name. Default: 0.0.0.0
mail_server	String	Host name of the SMTP mail server through which TWiki should send e-mail notifications. The mail server can be specified as a host name (e.g., mail.3tera.com) or as an IP address (e.g., 12.34.56.78). Default: 0.0.0.0 (mail is disabled).
allowed_hosts	String

The IP addresses configured in the usr_ip and mail_ip properties must be IP addresses available on your AppLogic grid. You can find them, together with the netmask, gateway and dns servers on the dashboard of your grid. We are working to make it possible for AppLogic to provide these addresses automatically

Resources

Resource	Minimum	Maximum	Default
CPU	0.3	40	1.05
Memory	272MB	36 GB	848 MB
Bandwidth	4 Mbps	1.6 Gbps	4 Mbps

User Volumes

The application itself uses several volumes, described below. They are part of the application and are already configured into the appliance instances. There are no volumes that need to be configured on the application boundary.

Application Volumes

The TWiki application has the following volumes:

Volume	Description
data	Shared file system holding TWiki configuration and cache data. This volume is configured as the data volume of the data NAS appliance.
twiki	TWiki scripts volume. This volume is configured as the content volume of the web servers. It is read-only so can be shared between servers if more are added.

Description

Users of the TWiki application can access it at the usr input (defined by the usr_ip address).

Operation

Implementation details

Application Architecture

This is a reference design for a Scalabe TWiki Application

It has the following components:

• one firewalled input gateway
• a web server
• a content file storage
• firewalled output gateway to e-mail server

The application infrastructure is shown below:

Notes

On inital setup of the wiki application the user must set a vaild email address for the webmaster. This address must valid on the mail server that is specified in the configuration of the application.

This is due to a limitation in TWiki that will not allow the user to add accounts if the webmaster email fails.

after starting the application
ssh into main.web
vi /mnt/content/twiki/data/TWiki/TWikiPreferences.txt
replace webmaster@example.NOSPAM.com with the valid email address.

Questions and Comments

To post questions and comments for this application, visit our forum.

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-- PeterNic - 15 Jan 2006