AWS Flashcards
What are the four disaster recovery strategies outlined by AWS in order of expense and RTO (low to high)?
Backup and Recover, Pilot Light, Warm Standby, Multi-size
What is RPO and what does it stand for?
Recovery Point Objective. The optimal point in time from which you’ll be recovering from.
What is RTO and what does it stand for?
Recovery Time Objective. The amount of time it will take for a backup system to be fully operational.
What is the least expensive DR solution recommended by AWS?
Backup and Restore
What durability does S3 have?
11 9s durability.
When would you use Pilot Light?
When you don’t want to pay the cost of having unused compute infrastructure but want to limit RTO to tens of minutes.
What happens when an EC2 instance that’s fronted by an ELB fails it’s health check?
The ELB stops sending it traffic.
When attached an ENI to an EC2, what’s the difference between a cold, warm, and hot attach?
Cold: attaching when the EC2 is being launched, Warm: attaching when EC2 is stopped, Hot: attaching when EC2 is running
When can you move an ENI from one instance to another?
When the ENI’s are in the same AZ and VPC but in different subnets
Would you choose RDS read replicas or RDS Multi-Region if you wanted to minimize RTO?
You would choose RDS Mutli-Region since read replicas are not updated synchronously.
Is DynomoDB an appropriate option for infrequently accessed data?
Yes
Are NACLs stateless? Are Security group stateless?
NACLS are stateless, Security groups are stateful.
What order are NACL rules evaluated in?
They are evaluated by rule number from lowest to highest.
You have been evaluating the NACLs in your company. Currently, you are looking at the default network ACL. Which statement is true about NACLs?
The default configuration of the default NACL is Allow, and the default configuration of a custom NACL is Deny.
What service can you use to ensure that resources you’ve deployed are within budget?
AWS Budgets
How many AZs can a subnet span?
Just one.
What addresses in the CIDR address block used by your Subnet are reserved and for what?
x. x.x.0 is the network address
x. x.x.1 is the VPC router
x. x.x.2 is for the DNS
x. x.x.3 is reserved for future use
x. x.x.255 is used for broadcast, which is in not supported by AWS
How many internet gateways can you have per VPC?
Just one.
Why wouldn’t you want to create a route out to the internet on your main route table in your VPC?
Any subnet created in your VPC will be associated with the main route table be default; if your main route table has a route table to the internet, all subnets will be public by default.
Why would you use a NAT gateway?
To enable an instance in a private subnet to have access to the internet.
How can you ensure an auto scaling group automatically scales out at a certain time every day?
Create a scheduled action
How can you block a specific IP address from accessing your subnet?
Using a Network ACL. You cannot use a security group to block a specific IP address.
How many network ACLs is your subnet associated with?
Exactly 1.
What is a VPC Endpoint?
A virtual device that allows communications between your VPC components and AWS services
What is the maximum bandwidth of a NAT Gateway?
They scale from 5 Gbps to 100 Gbps
When would you use an interface endpoint as opposed to a gateway endpoint?
Use gateway endpoints when you need to access DynomoDB or S3; otherwise use an interface endpoint. The interface endpoint uses an ENI while the gateway endpoint sits at the edge of your VPC.
Can you do transitive peering with VPCs?
No