List some minimal criterias/requirements that are necessary to identify a system as a cloud computing one.
- Using computers and other infrastructure, potentially running application, all accessible remotely (over the Internet usually)
- There is a cloud provider taking on some of the responsibility for the cloud resources.
- Financial benefits because of the “pay as you go” approach
Describe what the cloud shared responsibility model is³
When you move to the cloud, you share responsibility of your systems/applications
with your cloud provider.
How much responsibility you shift to the provider depends on what type of cloud service you are using, but the responsibiity for any cloud deployment is always shared between you and the cloud provider.
Increased control over your resources means a larger responsibility on your part. Decreased control results in more responsibility on the cloud provider’s part. This concept is called the shared responsibility model.
What are the 3 cloud models that exists ?
- The public cloud
- The private cloud
- The hybrid cloud
Describe what a public cloud model is
In a public cloud model, you use shared infrastructure that is accessible on a public network, usually Internet.
The network, storage and virtual machine (VMs) that your application uses are provided by a cloud provider and shared between all consumers of the public cloud.
Example: Microsoft Azure, Amazon Web Servivces (AWS), Google Cloud.
Why are public clouds often referred to as multitenant environments ?
Because with public clouds, you are sharing resources with other people/organizations. And each organization has a single distinct tenant.
Describe what a private cloud model is
The private cloud model provides of the attractive benefits of the cloud in a private environment that is dedicated to a single company.
A private cloud can be hosted in an on-premises environment, but it can also be hosted on a third-party hosting provider.
Why are private clouds often referred to as singletenant environments ?
Because the resources in a private cloud are dedicated to a single organization.
Is a private cloud infrastructure always owned by the individual company benefiting from this cloud ?
No.
The bottom line is that the difference between a public and a private cloud is the privacy of infrastructure and data. It doesn’t really matter who owns the infrastructure (the hosting provider, the customer company, etc.) or whether it is on premises or not.
Describe what an hybrid cloud model is
Hybrid clouds are a mixture of public and private clouds.
In a hybrid cloud environment, you might have an application that is running within the public cloud, yet it accesses data that is securely stored on-premises.
You might also have a scenario where your application and most of its resources are located on a private cloud, but you want to use services or infrastructure that are in a public cloud.
What is the cloud consumption-based model ?
It refers to the “pay-as-you-go” billing approach of the cloud. The ability to use only those computing resources you require at any particular time and to pay only for the time that you consume computer resources.
What are the advantages of the public cloud ?
- You shift the maximum amount of responsibility to the cloud provider
- You benefit financially by taking advantage of the consumption-based model
What are the disadvantages of the public cloud ?
- Your give up some control fo the infrqstructure. The amount of control you give up depends on the type of cloud service you choose, but no matter what, the cloud provider will control some portion of your infrastructure
- There are some security concerns: public cloud is opened to the public Internet. It is therefore available to anyone having an internet connection. Security measures are needed to avoid unauthorized access to your application and data or denial of services.
- the public cloud locks you into the specific configuration defined by the cloud provider. For example, suppose you have an application that needs a large amount of disk storage, but you only need a single CPU system to run it. In order to meet your disk space requirements, the cloud provider might require you to use a high-powered, multi-CPU VM, thereby increasing your costs unnecessarily.
What are the advantages of private cloud ?
- Security, privacy, often regulation
- Might be accessible without need of Internet access. And therefore used in places where internet access is not always available
What are the disadvantages of private cloud ?
- Spent: If you are hosting your private cloud on-premises, you will likely spend as much on IT as you would in a non-cloud environment. You will have to pay for hardware and virtualized systems for your cloud, and you’ll need IT staff who can manage the software and infrastructure for your cloud.
- Even if you decide tho use a 3rd party hosting provider, you might have some security concerns about your data. It’s often impossible to achieve full transparency when dealing with third-party providers, and you can’t always guarantee that data on your private cloud network will remain secured in a way that you require.
What are the challenges that come with hybrid cloud ?
- First, application development teams will need to ensure that data shared between the public and private cloud is compatible. This might require some specialized development skills and complex troubleshooting.
- The networking complexities in a hybrid environment can also be quite challenging, especially because network infrastructure at third-party providers might introduce problems that are difficult to troubleshoot.
- Finally, spreading application resources between a public and a private cloud might cause application slowdowns due to the geographical distance between systems running the application and the data the application uses.
What is Azure Stack ?
In order to make hybrid cloud easier for its customers, Microsoft provides Azure Stack. Azure Stack is sold as a package, including software and validated hardware to run it. Azure Stack allows you to run Azure services on-premises, making it easy to then transfer applications to the cloud with a minimal amount of work. Because the hardware is part of Azure Stack and has been validated by Microsoft, you don’t have the burden of attempting to determine hardware needs in order to deploy Azure Stack, but you do have to manage the on-premises hardware.
Which guaranties the cloud providers give to minimize the risk of problems that can affect availability of your application/data/services ?
Cloud providers offer a service-level agreement (SLA) that guarantees a certain level of availability as a percentage. An SLA will usually guarantee an uptime of close to 100 percent, but it only covers systems that are controlled by the cloud provider.
Explain why scaling up Often Adds Features
When you scale up, you often not only add more CPU power and memory, but you also often gain additional features because of the added power. For example, scaling up might give you solid-state disk drives or other features not available at lower tiers.
What is the lift-and-shift concept ?
With PAAS solutions, the cloud provider will ensure that common components necessary for data connectivity from your application to other systems are installed and configured.
That usually means that your application code works without you having to do any kind of complex configuration. In fact, this is one of the main benefits of using a PaaS service; you can often move your application from on-premises to a cloud environment by simply deploying it to the cloud. This concept is often referred to as lift-and-shift.
