Cloud Computing

What

It is the the on-demand delivery of IT resources over the Internet with pay-as-you-go pricing

• Common cloud services: compute, networking, storage, databases

• diagram
• they own and operate IT resources & infrastructure in their own data centers, that are typically distributed across the entire world
• as a customer, you can use the cloud infrastructure (rent/use IT resources managed by AWS) through cloud services!
• No need to provision/maintain your own data center

Formal definition - Characteristics

Definition of cloud defined by NIST

1. On Demand Self-Service
   • You can provision capabilities as needed w/o requiring human interaction
   • ex) using AWS CLI, no need to wait - u can just use it asap
2. Broad network access
   • capabilities are available over the network and accessed through standard mechanisms (http, https, ssh, etc)
   • if u need to visit a vendor, it’s probably not cloud
3. Resource Pooling
   • Sense of location independence - customers have no control or knowledge over the exact location of the resources (abstraction)
   • Resources are pooled to serve multiple consumers using a multi-tenant model (economies of scale)
4. Rapid elasticity
   • capabilities (resources) can be elastically provisioned & released to scale rapidly outward & inward with demand
   • to the consumer, the capabilities available for provisioning often appear to be unlimited
5. Measured service
   • resource usage can be monitored, controlled, reported, AND billed

Common Cloud Services

• Compute
• Networking
• Storage
• Databases

Types of Cloud computing

• diagram

Without cloud computing

• Advantages
  • Full control over your physical infrastructure & hardware
  • You know exactly where your computers (and data) are
• Disadvantages
  • Your responsibility to maintain the infrastructure and protecting it
  • Your responsibility for long term capacity planning & upgrading
  • Can’t react quickly to workload spikes (ex. more requests)
  • Pay for idle resources
  • Typically stuck to one or a few locations

Cloud Advantages

• Official source
• Reliability
  • Rely on AWS
    • AWS operates & maintains the infrastructure (maintenance, capacity planning & upgrades, security)
    • Service Level Agreements (SLA) are available for many key services
  • Build reliable applications
    • Various services help you build reliable applications, correctly & consistently (no matter the circumstances)
    • Reliable to keep up with traffic or demand in general
  • Rely on AWS Global Reach
    • They have data centers all across the globe
    • Allows you to fall back to a different region or data center in case
    • You can move your workload within mins to hrs (not days/weeks)
• Agility, Elasticity & Scalability
  • Agility
    • You can use cloud resources within seconds or minutes
    • You can configure and start a rented server on which you can install and run any software/workload of your choice in few clicks
    • Instant & easy
  • Elasticity
    • You can start using more/less resources whenever you need to VERY quickly
    • No long-term planning required
  • Scalability
    • Scale up or down as required
    • Use auto-scaling services to reduce manual workload
• Pay-as-you go
  • Generally, you only pay for what you’re using
    • If you don’t use it, simply no payment!
  • No fixed cost! → You trade fixed expense for variable expense
  • No CapEx (capital expenditure) for purchasing/operating your own hardware
  • Less OpEx (operating expenditure) since you only pay for service usage, not staff/power
  • Benefit from AWS’ economies of scale
    • AWS can realize discounts & savings on hardware procurements (+ advantages) which you couldn’t
• Global Reach & high availability
  • AWS own & operate a world-wide network of data centers
    • benefit with global reach
    • choose a perfect location
  • make available/faster to more customers worldwide for high availability

Cloud Architecture terms

• Availability
  • your ability to ensure a service remains highly available
  • ensure there is no single point of failure
  • Elastic Load Balancer (ELB)
• Scalability
  • your ability to grow capacity rapidly or unimpeded
  • scaling up (vertical) - upgrading to bigger server
  • scaling out (horizontal scaling) - adding more servers of the same size
• Elasticity
  • your ability to shrink and grow to meet the demand
  • EC2 Auto Scaling
• Fault tolerance
  • your ability to prevent failure
  • RDS Multi-AZ
• Disaster recovery
  • your ability to recover from a failure (highly durable)
  • do you have a backup, how fast can you restore the backup, does it work, etc
  • CloudEndure Disaster Recovery
  • Business Continuity Plan (BCP)