Hello, young padawan, we meet again after some time, I hope you have read part 1 and part 2, so let's continue with new interesting concepts.

SLA Cloud

[SOURCE: https://k21academy.com/1z0-1085/service-level-agreement-sla-in-oracle-cloud-oci/]

According to k21academy Cloud Service-Level Agreement is an agreement between a cloud service provider and a customer that guarantees a minimum level of service is maintained.

**So, what's the meaning of this? **Basically, an SLA sets the expectations between the customer (in this case us) and a cloud provider (AWS, Azure, and many more), this agreement describes the products or services to be delivery, a single point of contact for end-user problems, and the metrics of the process monitored and approved.

Total Cost of Ownership (TCO)

[SOURCE: https://toolsense.io/glossary/total-cost-of-ownership/]

According to techtarget it is an estimation of the expenses associated with purchasing, deploying, using, and retiring a product or piece of equipment.

**So, what's the meaning of this? **Basically, Total Cost of Ownership (TCO) is the amount of money you spend (purchases, support and others) for your specific product across its entire lifecycle.
For example, in a data center on-premise, it includes the initial acquisition of the hardware we need (CPU, RAM, SD, and many others), the repairs, the maintenance costs, upgrades, support contract, network, security, license in software we will use (Office, Windows Server, and many more), training of our staff, electronic bill and other cost it needs your data center to work.

Shared Responsibility Model

[SOURCE: https://aws.amazon.com/compliance/shared-responsibility-model/]

According crowdstrike, the Shared Responsibility Model is a security and compliance framework that outlines the responsibilities of cloud service providers (CSPs) and customers for securing every aspect of the cloud environment, including hardware, infrastructure, endpoints, data, configurations, settings, operating system (OS), network controls and access rights.

**So, what's the meaning of this? **Basically, Shared Responsibility Model explains what the cloud provider (such as AWS, Azure, GCP and many others) must monitor and protect from security threats related to cloud itself and its infrastructure such as hardware should be always working or the internet network is always guaranteed. On the other hand, end users (individuals and companies), are responsible for protecting data and other assets they store in any cloud environment such as firewall rules, user access and permissions.

If you want to read more about Shared Responsibility Model in real cases for big company, I recommend you to read these links:

• https://stratus10.com/blog/capital-one-data-breach-and-the-amazon-shared-security-model
• https://diginomica.com/capital-one-aws-incident-highlights-roles-and-responsibilities-cloud-customers-providers

This is the last post of basic terminology, the following post will be about AWS Services, my goal is to help you to learn about cloud and be able to achieve the first AWS Certification AWS Cloud Practitioner.

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