1. Lecture Flashcards
What is the cloud?
The practice of using a network of remote servers hosted on the internet to store, manage, and process data, rather than a local or personal computer.
What are the different cloud computing deployment models?
IaaS: Infrastructure as a Service
PaaS: Platform as a Service
SaaS: Software as a Service
What are the characteristics of IaaS?
- End-user applications delivered as a service, rather than by on-premise solutions
- Includes dedicated Virtual Machines (VM)
- Users configure the server type, operating systems …
- Scale up/down out/in
What are the characteristics of PaaS?
- Application platform or middleware is provided as a service on which developers can build and deploy custom applications on.
- Delivers and manages various development environments
- Environment and tools can be easily provisioned and torn down
What are the characteristics of SaaS?
- Computer, storing or other IT infrastructure are provided as a service, rather than as dedicated capability
- Internet hosted software
- Full vendor maintenance
- No upfront costs
- Pay for the services that are used
Explain the service model division of responsibility
- On-premises: Applications, Data, Runtime, Middleware, Operating system, virtualization, servers, storage, and networking is all managed by the user
- IaaS: Applications, Data, Runtime, and Middleware are managed by the user.
The rest is managed by the provider.
- PaaS: Applications and Data are managed by the user.
The rest is managed by the provider.
- SaaS: Provider manages all responsibilities.
What does to scale up/down (vertical scaling) mean?
Increase/decrease the CPU/memory or computing power of a VM
What does scale out/in (horizontal scaling) mean?
Increase/decrease number of VM
What are the cloud deployment models?
Private cloud
Hybrid cloud
Public cloud
What is a private cloud?
- Intended for a single tenant
- Can help reduce operating expenses
- Leverage existing capital expenses
What is a hybrid cloud?
- Bridges one or more private or public clouds
- Allows manipulation of CapEx and OpEx to optimize costs
What is the public cloud?
- Shifts CapEx to OpEx
- Offers pay-as-you-go pricing
- Supports multiple tenants
What are the advantages of using cloud services?
- Flexibility
- Reliability
- Cost-effectiveness (pay-as-you-go or consumption-based)
- Scalability
- Elasticity (Acknowledges peaks to increase resources)
- Current (No need for manual updating patches manually=
- Global
- Secure
Which aspects are summarized under the term flexibility?
- Scale up and down to meet requirements
- Charge for services on a fine grain level
- Easy and agile to deploy
- Highly automated
- Device- and location-independent
Which aspects are summarized under the term reliability?
- 24/7 support
- Vendor is responsible for hardware maintenance
- Vendor is responsible for software updates and maintenance for SaaS model
Which aspects are summarized under the term cost-effectiveness?
- Reduce of Total cost of ownership (TCO)
- Free up internal resources
- Lower capital expenditure
Describe a potential change/journey from on-premises towards SaaS
- On-Premises -> IaaS: migration requires re-hosting
- IaaS -> PaaS: requires complete application modernization, i.e.: refactor, rearchitect, and rebuild
- PaaS -> SaaS: requires a full replacement
What is a vendor lock-in?
- Company’s entire data is stored within a single vendor’s cloud storage
- The company relies on a single vendor for all of its computations
- Changing vendors can be very costly
What are the typical services provided by the cloud provider?
- Computer power (e.g. web applications)
- Storage (e.g. files and databases)
- Networking (e.g. secure connections between provider and company using the services)
- Analytics (e.g. visualizing telemetry and performance data)
What differentiates a VM, a container and serverless computing?
Serverless computing is only charged for the processing time used by each separate function. VMs and containers are charged while they are running, even if the applications are idle.
What are typical CapEx computing costs?
- Server costs
- Storage costs
- Network costs
- Backup and archive costs
- Organization continuity and disaster recovery costs
- Datacenter infrastructure costs
- Technical personnel
What are typical OpEx cloud computing costs?
- Leasing software and customized features
- Scaling charges based on usage/demand
- Billing at the user or organizational level
What are the benefits of CapEx?
- Planning of expenses at the start of a project/period
- Fixed costs > appealing when planning with limited budget
What are the benefits of OpEx?
- Pay-as-you-use
- No upfront costs
- Appealing if costs fluctuate
- Dynamically managing costs
