VL 1 Flashcards
IT-Trends
Outsourcing (everything is on premise)
Recentralization
Edge Computing (reduce latency)
Resource sharing instead of overprovisioning (reduce costs)
Server Consolidation (virtualize servers)
Green computing (reduce energy consumption)
Autonomous computing (automatically recover from errors)
IT as a Service
Pay per use
Scalability (dynamically adapt resources to needs)
Economy of scale (cloud provider buys a lot of servers -> cheaper for you)
Environmental sustainability (data center in island -> no electrical energy to cool off)
Cloud Service Models
Own IT: infrastructure, runtime, application logic, data
IaaS cloud: infrastructure provided (Amazon WS, Openstack, Alibaba)
PaaS cloud: infrastructure + runtime provided (AWS, Google App engine)
SaaS Cloud: infrastructure + runtime + App logic provided (google apps, Microsoft 365)
IaaS
Offers: servers, storage, networking
Technology: commodity hardware, virtualization of servers, storage, networking
PaaS
Offers: App infrastructure services, server less computing
Technologies: service oriented architecture, scalable application middleware (db, filesystems)
Automatic scaling, Version management
SaaS
Offers: consumer or industrial applications
Technologies: standard apps as well as cloud native apps
Auto scaling(more people can use it)
Multi-tenancy (multiple users use one instance)
Deployment models
Public Cloud (Amazon): it resources provisioned over internet via web apps or services from off-side third party provider
Community cloud (only accessible for 1 community)
Private cloud (LRZ): it services offered via private networks for exclusive use of one client. Full control of resources, Build and managed by company’s Own IT organization
Hybrid cloud: private + public
Protect data or avoid overflow for computation: run on your servers, if capacity not sufficient -> use public cloud
Cloud characteristics
On demand self service
Broad network access
Resource pooling
Rapid elasticity -> react to changes of app demand
Measured service: keep track of how much is used of the service
Amazon EC2 provides
Virtual machines running inside Amazon Cloud
Ephemeral storage tied to VM
Block storage that persists over time and can be mounted in the VM
Virtual firewall to secure network in the cloud
Based on Xen Hypervisor
Cloud pros
Economy of scale
Scalability
Elasticity
Rapid deployment
No capital investment
Fault tolerance
Cloud cons
Security
Controllability
Vendor lock-in
Cost, monthly fees
Limited trust in providers
Breaking SLAs
