In this blog, I will cover different models for deploying Cloud services.
Following are the broad categories for deploying Cloud services.
- Private cloud
- Public cloud
- Hybrid cloud
- Community cloud
I found the following pictures in the internet which illustrates the Cloud types very well.
Private Cloud is where an Enterprise consolidates its internal resources into a Cloud and makes it available as an Elastic service to its employees or to its customers. Not all resources within an Enterprise qualify itself to be called as Cloud. As long as the resources satisfy the common cloud criterion like Elasticity and capability to provision services without user intervention, it can qualify as Cloud. Private cloud can be managed locally by the Enterprise or can be managed by partners. Private cloud does not have multi-tenancy where multiple enterprises share a common resource pool. Private cloud does not automatically provide better security than Public Cloud, it is needed to invest in both physical and virtual security to make Private cloud safe. Examples of Private cloud include clouds maintained by Enterprises.
- Usual cloud advantage of Elasticity, ease of use.
- Easier to conform with country bylaws since there is more control over where data is stored.
- Confidential information will be safe.
- If Private cloud is efficiently utilized, it is possible that over a period of time, Private cloud might work out to be cheaper.
- Capital investment is needed, need to plan for maximum resource usage.
With Public clouds, Cloud providers maintain all the infrastructure and Enterprises pay the cloud provider based on the usage. Multiple tenants or Enterprises share the same infrastructure. Examples of Public cloud include AWS, Google compute Engine, Microsoft Azure. Public clouds are ideal for smaller companies or startups because there is no capital investment involved, companies can focus their energy towards their core expertise rather than worrying about creating and maintaining IT infrastructure.
AWS has a service called VPC(Virtual private cloud) where Enterprises get more control over ACL, Subnet, Security groups using which different access mechanisms are available for different resources. Even though it uses private cloud in the naming, its still a public cloud service.
- Get all advantages of Cloud like Elasticity, ease of setup without any capital expenditure.
- Need to entrust confidential data to external Cloud providers.
- If the cloud provider gets bankrupt, need to have ways to recover data.
- Its difficult to obey country bylaws regarding data storage location.
The most popular cloud categories currently are Private and Public cloud, but it looks like the industry is moving more towards Hybrid cloud. With hybrid cloud, Enterprises keep their critical and confidential applications and data in private cloud and put the less critical stuff in Public cloud and connect the 2 clouds using VPN technologies.
- Get best of Private and Public cloud.
- Inter-cloud technologies are still in infancy stage.
Community cloud is a type of private cloud where multiple communities build a private cloud for sharing within the community. This is a common practice within Government organizations.
Looking at the different cloud models, its not correct to say that 1 Cloud type/model is better than the other. Its mostly about choosing the correct model based on the need. For example, for smaller enterprises, Public cloud could be a better option, while for bigger enterprises, private or hybrid cloud could be a better option.
- Comparing Cloud computing options
- Types of Cloud computing
- Cloud application architectures – By George Reese