The Cloud infrastructure is built on Servers, SAN and VM. Cloud vendors will deploy largely similar infrastructure in order to facilitate Cloud deployments and scalability. This could include hardware federation and federating VMs. A very typical deployment model for the Cloud might look like the following:
Figure: 2 data-centre Cloud system
Many cloud systems have a primary and then a backup data-center. Within a system such as AWS or Google Cloud, these centers would be called Availability zones, within the same region, or perhaps 2 regions running within a distinct Virtual Private Cloud network.
In both centers or zones, we have VMs, a management platform, an identity authentication system, and backup and recovery systems which span both datacentres. In this configuration, both physical servers and virtual servers are shown, all connecting to a shared SAN storage, which in the case of the primary datacentre, is replicated across to the secondary datacentre to facilitate disaster recovery and failover should services at the primary datacentre fail. Notice that there is a firewall device located in the centre, indicating a secure network connection between datacentres that allows traffic to be redirected. This also facilitates failover of both cloud management nodes and guest/customer VMs if necessary. In the event of a total outage at the primary datacentre, the secondary datacentre could assume all cloud services.
The key to Cloud computing is the VM and the server infrastructure. What does it look like?
A VM and Cloud Hardware:
Installing a hypervisor onto each physical server provides for the best utilization of the hardware through multiple VMs. Some hypervisors are more mature than others, having more APIs and extensibility to integrate with other systems such as the SAN or server hardware management systems.
Key to virtualization
The key to virtualization, beyond squeezing more VMs into each physical server, is the ability to have VMs failover or quickly reboot on any other available physical server in the farm. Depending on the situation and hypervisor’s capability, this should be done so that a customer does not notice an outage. With this capability, the Cloud IaaS/PaaS provider can move all online VMs from one server to any other servers in the farm, facilitating easy maintenance or repair.
Server Configuration for the Cloud
The configuration includes:
- Two network switches for fiber Ethernet and fiber SAN connection to the datacentre infrastructure
- Three cloud management servers that will run the cloud management soft- ware platform
- A SAN storage system with seven disk trays connected through SAN switches to server chassis backplane
- Two high-density server chassis, each with 16-blade servers installed, running your choice of hypervisor and available as customer VMs (also called capacity VMs)
Additional expansion cabinets would be installed next to this notional cloud configuration with extra capacity servers and storage. Cloud management servers do not need to be repeated for every rack, but there is a limit, depending on the cloud management software vendor you choose and the number of guest/capacity VMs. When this limit is reached, additional cloud management servers will be needed but can be federated—meaning that they will be added under the command and control of the central cloud management platform and function as one large cloud that spans all of the expansion racks.