GGUS Architecture

The GGUS architecture consists of the following three layers:

• 1. Web-based Client (based on httpd and php scripts) with VOMS user synchronization interface
• 2. Logic Server (based on ARS Remedy) with Web service (based on apache tomcat) and Email interface
• 3. Database (oracle based) for tickets and Portal data

Every layer is constructed for three independent environments: development, testing and production. The development process is restricted by development and testing environments. All scripts are going into test (checking software quality) and production by using standard package management software for operating system. Hence, the announced downtime is reduced, but cannot be completely avoided because of workflows update (intra ARS Remedy coding).

Vision for high availability (HA) GGUS Service is to bring the GGUS architecture into the highly available infrastructure. This task is done for all GGUS hosts and consists of the following components:

1. Virtualisation

• Is based on VMWare ESX Clusters
• Has redundant connection to Networking and Storage (which is also complete redundant)
• Include two completely independent instances: Campus South and North (around 12 km in between)
• All hosts are virtual machines
• Daily virtual machines backup

2. Networking

• 10 Gigabit connection
• Is redundant between Campus North and South
• Is located on DMZ (perimeter or demilitarized network)
• Use redundant Domain Name Servers (DNS)
• Internet Connection use two different Internet service providers

3. Hosts

• Every layer is hosted under own virtual host
• Based on Redhat Linux 6 operating system
• Software configuration is done by the configuration management tool (cfengine v.3)
• Database synchronization is done by replication without clustering (cheap solution)
• Switching between replicated hosts is partly automated
• Are under On-Call-Duty service monitoring (24/7)