Sutions Architect Associate Level Flashcards
Network has two sorts of IPs what are they?
IPv4 & IPv6
How would you describe IPv4?
It’s 4 numbers separated by 3 dots & is the more common IP format used online (ex. 1.160.10.240)
How would you describe IPv6?
It’s a less common IP and it’s a long set of number and letters & used more for IoT (ex. 1900:4545:3:200:f8ff:fe21:67cf)
What are some features of a public IP?
- Public IP means that the machine can be identified on the internet (WWW)
- Must be unique across the whole web (not two machine can have the same public IP)
- Can be geo-located easily
What are some features of Private IP?
- Private IP means the machine can only be identified on a private network only
- The IP must be unique across the private network
- But two different private network (two companies) can have the same IPs
- Machine connect to WWW using a NAT + internet gateway (a proxy)
- Only a specified range of IPs can be used as private IP
What are some features of Elastic IPs?
- When you stop and then start an EC2 instance, it can change its public IP
- If you need to have a fixed public IP for your instance, you need an elastic IP
- An elastic IP is a public IPv4 IP you own as long as you don’t delete it
- You can attach it to one instance at a time
- With an elastic IP you can mask the failure of an instance or software by rapidly remapping the address to another instance in your account
- You can only have 5 elastic IP in your account (can have AWS increase it for you though)
Why should you try to avoid using elastic IP?
They often reflect poor architectural decisions and you should instead use a random public IP and register a DNS name to it
________ can be used when you want to have control over how your EV2 instance is placed in AWS infrastructure
Placement groups
What are the 3 strategies you can use with placement groups?
- Cluster - clusters instances into a low-latency group in a single availability zone (EC2 instance are on the same hardware)
- Spread- spreads instance across underlying hardware (max 7 instance per group per AZ) and used for critical applications
- Partition- spreads instances across many different partitions (which rely on different set of racks) within an AZ. Scales to 100s of EC2 instance per group (Hadoop, Cassandra, kafka)
What are Pros and Cons of using cluster placement groups and it’s use case?
Pros: great network (10 Gbps bandwidth between instances)
Cons: If the rack (hardware) fails, all instances fails at the same time (so you increase the failure risk)
Use case: Big data job that needs to complete fast & application that needs extremely low latency and high network throughput
What are the Pros and Cons of spread placement groups and it’s use case?
Pros: can span across availability zones, reduced risk is simultaneous failure, & EC2 instances are on different physical hardware
Cons: Limited to 7 instances per AZ per placement group
Use case: Application that needs to maximize high availability & critical application where each instance must be isolated from failure from each other
What are the features of the partitions placement groups and the use case?
- Up to 7 partitions per AZ
- Can span across multiple AZs in the same region
- The instance in a partition do not share racks with the instance in the other partitions
- A partition failure can affect many EC2 but won’t affect other partitions
- EC2 instance get access to the partitions information as metadata
Use case: big data applications who are partition aware such as HDFS, Hbase, Cassandra, kafka
What are elastic network interfaces (ENI)?
They’re logical component in a VPC that represents a virtual network card
ENI can have what attributes?
- Primary private IPv4, one or more secondary IPv4
- One elastic IP (IPv4) per private IPv4
- One public IPv4
- One or more security groups
- A MAC address
- Bound to a specific availability zone
You can create ENI ____________ and attach them on the fly (move them) on EC2 instance for failover
independently
