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Describe Cloud Computing
- Delivery of computing services over the internet
- Includes common infrastructure like VMs, storage, DBs & networking.
- Also expands traditional IT offerings to cover IoT, ML and AI (for example).
- Is not constrained in the same way traditional datacentre ops are: What you pay for is the convenience of large, elastic scaling and abstracting the physical maintenance of hardware
- Traditionally, corporate physical datacentre space is maintained by the company and they will ensure the security, maintain or replace the servers if needed, etc (in practice most corporate datacentres are rented from providers but only the physical space and security elements: They may also take care of replacing hardware at the request of the customer, or the customer themselves may be responsible for this either in person or in collaboration with the DVC owner
- It department is responsible for maintaining infrastructure and software (OS, networking kit, updating software, whatever)
- Shared responsibility abstracts the datacentre itself away from the company and means the provider takes care of physical security, power, cooling, network connectivity and so on (much like a traditional datacentre provider), but on a huge scale so you can request resources whenever you want
- Customer is responsible for data and information stored there, and the access security of it
- Responsibilities can change depending upon the situation: cloud SQL means your are responsible for the databases themselves, but the provider is responsible for the maintenance of the underlying SQL Server instances, hardware, patching etc, but if you use SQL installed on a VM, they you are responsible for the patching, updates, how the physical files are stored on the VM disks etc
- On-premise datacentres mean you are responsible for everything (on-premise doesn't always mean physical on-premise: You can rent dedicated space in a datacentre provider but that does not mean it is a cloud solution). Cloud computing can remove a number of responsibilities from users which means they can focus on the things that make a business rather than the day to day maintenance. However, the exact nature of cloud services can mutate the shared responsibilities one way or another:
- Iaas means the consumer has most responsibility for the consumer since you are creating your own infrastructure within the cloud provider which will need maintenance (albeit underlying systems are still maintained by the provider as is physical security, power, connectivity). Think of a corporate network being hosted in a cloud provider along with the disk storage and all the rest that goes along with a normal corporate network, as well as possibly some software offerings, VMs etc.
- SaaS involves the least consumer responsibility since you are mostly just deploying code to or consuming services that already exist as a commodity, such as Function Apps or Web Apps etc.
- PaaS is a middle ground with responsibility more evenly shared between provider and consumer
- Consumers will always be responsible for:
- The information and data stored in the cloud
- Devices that are allowed to connect to your cloud
- The accounts and identities of the people, services and devices within the organisation
- Cloud providers will always be responsible for:
- The physical datacentre
- The physical network
- The physical hosts
- The chose service model will determine responsibility for things like:
- Operating systems
- Network controls
- Applications
- Identity and infrastructure
Cloud models define the deployment type of cloud resources. The three main models are private, public and hybrid.
Essentially an evolution of the corporate datacentre. It's a cloud delivering services over the internet that is used by one single entity. This provides much greater control for the company and the IT teams. But it comes at greater cost and fewer of the benefits of public cloud deployments. Our current datacentre solution could be thought of as a kind of private cloud since it is not physically in our offices, but you can host a private cloud in a on-premise datacentre too.
- You have complete control over resources and security
- Data is not co-located with other organisations' data
- Incurs a large capital cost for startup and maintenance
- You are responsible for all hardware maintenance and updates
This is built, controlled and maintained by a third-party cloud provider. Anyone who wants to purchase cloud services can access can use resources, but this does not mean that anyone can access your cloud resources. The general availability is the key difference between public and private clouds.
- No capital expenditure required for scaling up
- Apps can be quickly provisioned and deprovisioned
- Pay for what you use
- But you don't have complete control over resources and security
A computing environment that uses a combination of public and private clouds in an inter-connected environment.An example might be a private cloud that can surge for increased, temporary demand by deploying public cloud resources. This also allows you to choose where you deploy a service: The private cloud offers an extra security layer over the public cloud.
- Provides most flexibility
- Freedom to decide where an application runs
- You can still control security, compliance of legal requirements
An increasingly likely scenario where a consumer engages multiple public cloud providers. You may be migrating from one to another or pick and choose services from each that best suit your needs. However you must then manage resources and security in all the cloud environments you use
A set of technologies that help you manage a cloud environment, either public solely on Azure, private cloud in a datacentre, hybrid or even multi-cloud.
Allows you to run your VMware workloads in Azure with seamless integration and scalability. USeful if you are already invested in VMware in a private cloud environment but want to expand into Azure.
- IT infrastructure expenditure traditionally falls into CapEx (one-time up-front costs to or secure tangible resources) or OpEx (on-going costs of running, a service or using a product over time).
- Cloud computing falls under OpEx thanks to the consumption-based model. You don't pay for the hardware or datacentre space or anything else associated with the physical equipment: You pay to use it, or effectively rent, the resource. But you only pay for what you use.
Benefits include:
- No upfront costs
- No need to CapEx expensive resources which you might not use to their fullest extent, or possibly even under-specify leading to costly and time-consuming expansions of physical hardware/datacentre space
- Ability to pay more for resources if and when they are needed
- Ability to stop paying for resources that are no longer needed
- Traditional datacentres are easy to over- or under- spec. Both can be costly mistakes
Cloud computing allows you to rent compute and storage when you actually need them and to then hand back and stop paying for those resources when you don't, without the need to worry about physical space or hardware. You are billed only for what you use, but bitter experience shows that you must be careful to keep an eye on costs as it is very easy to spend more than you might think you will.