EC2 Flashcards
What are the capabilities of EC2
Renting Vm’s (EC2)
Storing data on virtual drives (EBS)
Distributing Load(ELB)
Scaling services (ASG)
How is traffic allowed in/out of EC2 machines?
Security Groups
What acts as a firewall for EC2 instances?
Security Groups
What do Security Groups regulate?
Access to ports
Authroized IP ranges
Control of inbound/outbound network
Can Security Groups be attached to multiple instances?
Yes
Is a Security Groups locked down to a region/VPC combo?
Yes
Where does the Security Group live?
Outside the EC2 instance
How many Security Groups should maintain SSH Access?
One
If application isnt accessbible(timed out) what’s wrong?
Security Groups issue
If application gives a “connection refused” error, what’s wrong?
Application error or its not launched.
What are the inbound/outbound traffic defaults
Inbound is blocked/outbound is authorized.
What are the fundamentals of a public IP?
Machine can be identified on the internet
IP is unique
Can be geo-located
What are the fundamentals of a private IP?
Identified on private network only.
IP unique on private network.
How do machines connect to internet(WWW)?
internet Gateways(Proxies)
Can you use any range for private IPs?
No, only specific range is used.
What is an Elastic IP?
Fixed public IP.
How many instances can an Elastic IP attach to?
One instance at a time.
What happens when you stop, then start an instance?
The IP changes
How many Elastic IP’s can you have?
5 (you can ask for more)
What should you avoid using Elastic IPs?
Reflect poor architectural decisions
What should you do instead of using Elastic IPs?
Use random public IP and register a DNS name to it.
Or, use a Load Balancer and dont use a public IP
By default, your EC2 machine comes with what?
- A private IP for the internal AWS Network
* A public IP, for the WWW.
When we are doing SSH into our EC2 machines what can we do, what cant we?
- We can’t use a pr ivate IP, because we are not in the same networ k
- We can only use the public IP.
