Cloud Architecture

• Solutions architect is a role in a technical organization that architects a technical solution using multiple systems via researching documentation and experimentation.
• Cloud architect is a solutions architect that is focused solely on architecting technical solutions using cloud services.
• In the actual marketplace, solutions architect is often used to describe both a cloud architect and a solutions architect, and the terms can vary depending on the locality and how companies use them.
• Disaster recovery is the ability to recover from a failure.
• Business requirements include availability, which is the ability to ensure a service remains available.
• Fault tolerance is the ability to prevent a failure.
• Elasticity is the ability to shrink and grow to meet the demand.
• Scalability is the ability to grow rapidly or unimpeded.
• High availability is the ability for a service to remain available by ensuring there is no single point of failure and meeting a certain level of performance.
• On AWS, high availability is achieved by running workloads across multiple availability zones to ensure servers or applications remain available even if one or two availability zones become unavailable.
• Elastic load balancer is used to evenly distribute traffic to multiple servers in one or more data centers.
• If a data center or server becomes unavailable or unhealthy, the load balancer will route the traffic to only the available data centers within the server.
• Just because you have additional servers doesn't mean you are available, you might need to meet a particular threshold of availability, for example, you might need to have at least two servers always running to meet the demand.
• High availability is based on the demand of traffic.
• High availability is the ability for a service to remain available by ensuring there is no single point of failure and meeting a certain level of performance.
• On AWS, high availability is achieved by running workloads across multiple availability zones to ensure servers or applications remain available even if one or two availability zones become unavailable.
• The way to ensure high availability on AWS is to use an Elastic Load Balancer, which allows for the even distribution of traffic to multiple servers in one or more data centers.
• If a data center or server becomes unavailable or unhealthy, the Elastic Load Balancer will route the traffic to only the available data centers within the server.
• Just having additional servers does not guarantee availability, as a certain threshold of availability might need to be met, for example, having at least two servers always running to meet the demand of traffic.
• High scalability is the ability to increase your capacity based on the increasing demand of traffic, memory and computing power.
• Vertical scaling also known as scaling up is where you upgrade to a bigger server.
• Horizontal scaling also known as scaling out is where you add more servers of the same size.
• High Elasticity is the ability to automatically increase or decrease your capacity based on the current demand of traffic, memory and computing power.
• Horizontal Scaling In is where you remove underutilized servers of the same size.
• Auto Scaling Groups also known as (ASG) is an AWS feature that will automatically add or remove servers based on scaling rules you define based on metrics.
• Fault Tolerance is the ability for service to ensure that there is no single point of failure. Preventing the chance of failure.
• Fail-overs is when you have a plan to shift traffic to a redundant system in case the primary system fails.
• RDS Multi-AZ is when you run a duplicate standby database in another Availabilty Zone in case your primary database fails.
• High Durability is the ability to recover from a disaster and to prevent the loss of data.
• Disaster Recovery are solutions that recover from a disaster.
• Things to consider when looking for High Durability:

  1. Do you have a backup?
  2. How fast can you restore that backup?
  3. Does your backup still work?
  4. How do you ensure current live data is not corrupt?
• Business Continuity Plan (BCP) is a document that outlines how a business will continue operating during an unplanned disruption in services.
• Recovery Point Objective (RPO) the maximum acceptable amount of data loss after an unplanned data-loss.
• Recovery Time Objective (RTO) is the maximum amount of downtime your business can tolerate without incurring a significant financial loss.
• Disaster Recovery Options:

  1. Backup & Restore - backup your data and restore it to a new infrastructure.
  2. Pilot Light - Data is replicated to another region with the minimal service running.
  3. Warm Standby - Scaled down copy of your infrastructure that is already running just waiting to be scaled up.
  4. Multi-site active - Exact replica of your infrastructure always running in another region.
• Recovery Time Objective (RTO) is the maximum acceptable delay between the interruption of service and restoration of service. This objective determines what is considered an acceptable time window when service is unavailable and is defined by the organization.
• Recovery Point Objective (RPO) is the maximum acceptable amount of time since the last data recovery point. This objective determines what is considered an acceptable loss of data between the last recovery point and the interruption of service and is defined by the organization