Module 2: Technology Flashcards
What should you consider when choosing a region?
- Available services and features, not every region has all services.
- Cost of the service varies per region.
- Latency, proximity to users.
- Disaster recovery (multiple regions)
- Security & Compliance
What are availability zones?
There are multiple availability zones per region, these are physically separate locations that are connected via private fiber for low latency between data centers. This is useful because they’re on separate power grids and flood plains so you get resiliency by spreading across an availability zone.
What is an Edge Location?
We don’t have direct control over them, and they exist outside of the normal region infrastructure.
An example use is a CDN hosted in the US. UK users might be getting the content delivered via a cached CDN in the UK to improve the experience.
An Amazon VPC spans a single ______.
Region, so it spans multiple availability zones.
When launching a VPC against several AZs, what needs to be assigned to every single AZ?
A Subnet, the structure is
VPC -> Subnet -> Instance
So everything is technically stored in a Subnet, which is placed on an AZ
Explain the Three-Tier Architecture.
- Load Balancing Tier
- Application Tier
- Database Tier
Each tier is within a single VPC that spans multiple AZs. Each tier on each AZ gets its own subnet. Load balancing tier handles routing to what’s available in the AZs.
How does traffic go from a VPC to another network? What tools do we need to get this to work?
Routing to an Internet Gateway.
We need to create an Internet Gateway and a Routing Table that has an IP range that directs traffic to the Internet Gateway. We then assign this routing table to a subnet.
How does the Network Access Control Lists (NACL) help us?
Allows us to set a subnet level firewall for services. Example we can have a subnet that only accepts traffic on port 80 from anyone but port 3306 is also accepted if originating from within the VPC.
How do Security Groups help us?
They’re firewalls for individual instances, so we can go to the level of saying this EC2 instance only accepts requests on port 80.
Network security, what are our layers of security? Explain a little about each one.
- Routing - Restricts traffic coming into/out of the VPC entirely.
- Network Access Control List (NACL) - Firewall for a subnet. Restricts ports in/out of a given subnet
- Security Groups - Firewall for an instance. Restricts ports in/out of a given application.
What benefits does Amazon Route 53 provide us?
- Register Domains, use AWS nameservers
- Public & private DNS Zones (Use within private VPC)
- Automated VIA API
- Healthchecks
- Different Routing methods
What are the different Routing Methods that Route 53 provides us? How are they useful?
- Latency - Connect a user to the server that has best experience
- Geographic - Provide user with connection to application specific to their location.
- Failover - If an endpoint fails, we can automatically push users to the working application
- Weighted Sets - Allows A/B testing on applications.
What is an AMI? What purpose does it serve?
Amazon Machine Image, it’s a bit for bit copy of root for a given machine. We can use these as containers. So we can boot up an EC2 instance, install software we need, create another image then duplicate the machine easily.
Explain Block Storage vs Object Storage.
Block storage we can update small “blocks” of data making it best for random IO. It can also be mounted.
Object Storage in contrast needs to update the entire object if anything changes and cannot be mounted.
How long are logs stored in Cloud Watch? Can we extend this time? How?
2 Weeks, we can automatically move logs to an S3 bucket for indefinate storage if needed.
