Virtualisation
Born in the 1960's on mainframe systems, virtualisation has been brought to the mainstream by VMware. Founded in 1998 VMware has pioneered x86 virtualisation and created an industry which they now share with Xen (now Citrix), Parallels and Microsoft, etc. Virtualisation has become a production ready technology used by almot all of the FTSE 100 and Fortune 500 (Source: VMware).
The benefits of virtualisation are now well documented and include decreases in costs and server rollout times (Source: ). By virtualising your datacentre infrastructure you can create an agile environment that is more capable than an equivalent physical infrasturcture.
Virtualisation Automation
Virtualisation is a platform which can provide considerable
improvements to an organisations infrastructure.
Automation adds to virtualisation to make possible a range of more
sophisticated and beneficial abilities. These range from business
contiuity functionality such as automated failover to disaster recovery
servers, through to automated turning on and off of physical and
virtual servers to meet "green" goals and lower running costs.
An example we built
Enough theory...
Here is an example build that was built to show the power of an
automated, virtualised infrastructure. A web application in used in a
test environment was migrated (physical to virtual {p2v}) into an
environment managed by Cassatt Collage and running on VMware ESX
server(s) using HP and generic x86 servers.
The service consisted of a HTTP load balancer, two web
servers and three database servers.
Each of the servers was "imaged" from the physical servers. Two of the
physical servers were repurposed as Cassatt Collage controller node
servers. Another was built as a VMware ESX server; managed by the
Cassatt Collage installation. This ESX installation was then used to
build configurations for the load balancer, web and database servers.
Once built the system was configured to run with a minimum of 1 ESX server and up to 3 in total, a minimum of 2 and a maximum of 5 database servers, 1-3 web servers and 1 load balancer. Once ready the system ran with the Collage controller node running on two physical servers and a ESX server running opn a physical server. The 2 database servers and single web and load balancer servers ran as virtual machines.
Testing...
To simulate a hardware failure the ESX server was physically
unplugged from the power socket.
The active Cassatt Controller, detected the loss of the server and
immediately started to build "from bare metal" and identical ESX
server. Once build and online the database (virtual) servers were
started. Once this had competed the web server and load balancer
servers were started simultaneously.
To show automated response to load, a HTML traffic generator was targeted at the test environment. As load increased beyond acceptable service levels, Collage started new web server instances up to the specified maximum level of 3. The web traffic generated additional load on the database tier and Collage started 3 more database instances.
As the last of the database virtual servers was started a threshold was passed for maximum load on a single ESX server. To cope with this additional load a new ESX server instance was build "from bare metal" automatically. Once active some of the virtual servers were automatically migrated (vmotion) to the new ESX server; balancing the load between both servers.
Back to normal...
Once we had observed the infrastructure automatically adjust to the
load were were generating, we turned off the HTML load balancer. On
detecting the decreased load, the system shutdown a single database
server and a single web server. Once this had completed, the system
detected that the load on the ESX servers was below optimal. It then
proceeded to migrate all the virtual servers from one server to another
and then shutdown the now empty ESX server. This process continued
until the infrastructure was running on the minimum number of physical
and virtual servers required.