Module 8 Flashcards
On prem data centre can cause latency for users that are geographically far away.
With this in Mind, using the cloud can save ____ and give you_______ ______ to customers in different GEOss
Cloud can save cost and give you local presence to customers in different GEOs
Several strategies and patterns used by software architects to make complex systems easy to design/build/maintain etc
Loosely coupled architectures via:
N-Tier Architecture
An N-Tier Architecture divides an app into…
Divides app into 2 or more logical tiers
How do the tiers access each other within an N-Tier Architecture
- Higher tier can access lower tier but not the other way round
Tiers help separate concerns and are typically reusable
How does this arcitecture help maintanenace?
- This also helps maintenance, can be updated or replaced inderpendantly + new tiers can be added
Give an example of a simple 3 Tier architecture
- 3 tiers referes to an N-Tier architecture with 3 tiers. e.g. Web (Interface), App (Business Logic), Data (DB or other storage) Tiers. This works as:
- User clicks Place order and request is sent to web tier
- Web tier passes fdata to app tier to validate payment and check inventory
- App tier passes to data tier where data is stored
What is an Azure Region
Azure Region
One or more data centers within a specific geographic location
A vNet is a logically isolated network on Azure, similar to networks in HyperV, VMWare and other clouds.
What does a vNet allow for…
- Allows for secure comms between each other, intrernet and on prem networks
How many regions are Azure vNets scoped to
Azure vNets are Scoped to a single region
What can be used to connect vNets to different regions
- vNets from different regions can be connected using vNet peering.
Segmenting a vNet into one or more subnets allows for
- Segmented into one or more subnets, this allows for organising + securing of resources in discrete sections
How/Why could/would you keep some tiers on prem and others in the cloyd
- You can also keep some tiers on-prem, i.e. Web Tier in cloud keeping other tiers on-prem allowsing tighter control.
- A VPN gateway would provide a secure connection between Azure + On prem.
- Azure manages physical H/W, you config vNets and gateways enabling you to treat vNet like your own.
- You can choose which networks your vNet can reach (i.e. public internet or other networks in the private IP space)
What are NSGs
- Allows or denies inbound traffic to Azure resources
- Essentially cloud level firewall
- You can config NSG to allow only traffic from known sources (IPs) you trust
What does Azure Load Balancer help to ensure?
- Azure Load balancer helps ensure site runs 24/7, when you also want to do maintenance (and there is no “good” time for down time)
- Azure Load balancer can also alleviate performance issues with too many users
What does availability refer to?
Availability = how long a service is up and running with out interruption
What does High Availability refer to?
High Availability (HA) = services up and running for a long period of time
100% Availability is difficult to achieve - many teams strive for 5-9’s (99.999%)
What does resiliency refer to?
Resiliency - Ability to stay operation during ab-normal conditions, these incl: Nat Disasters, Sys Maintenance, Spikes in traffic, Threats (DDoS attacks etc)
A Load balancer distributes traffic amongst systems in a pool helping to achieve….
Helping to achieve High Availability and Resiliency