EC2 Flashcards
DIRTMCG - what are the different types of instances?
D for Density I for IOPS R for RAM T cheap general purpose (think T2 Micro) M main choice for general purpose C for Compute G for Graphics
HVM
Hardware Virtual Machine
PV
Paravirtual
One subnet….
…equals one availability zone.
When editing a security group, the rules apply how quickly?
Immediately
How are Security Groups stateful?
If you allow a specific port inbound, that protocol will automatically be allowed on the outbound.
Is termination protection on or off by default?
Off. You must turn it on.
If a spot instance is terminated by you, who pays for the hour?
You do, as you terminated it.
If a spot instance is terminated by AWS, who pays for the hour?
Nobody - the hour is free.
How many IOPS does GP2 (General Purpose SSD) give you?
Up to 10,000
How many IOPS does IO1 (Provisioned IOPS SSD) give you?
More than 10,000
What’s the best EC2 Instance Type for NoSQL databases or fast data warehousing?
I2, IOPS
What’s a good EC2 Instance Type with a lot of storage?
D2, Dense Storage
C4 and C3 are what?
Compute Optimized instance types, best suited for CPU Intesive Apps and DBs
When you delete an EBS-backed instance, what happens to the root volume?
The default action is for the root volume to be deleted. This can be changed for each instance.
How can I encrypt the Root Volume?
The root volume cannot be encrypted by default by AWS ; you need to use a third-party tool (eg, Bitlocker) to do this.
Where do EBS snapshots live?
S3
Are snapshots full or incremental?
Incremental.
Why can’t I share this snapshot?
It’s encrypted. You can only share unencrypted snapshots.
How do snapshots handle encrypted volumes?
Snapshots of encrypted volumes are encrypted automatically. Volumes restored from encrypted snapshots are encrypted automatically.
Why can’t I create a snapshot of the root volume?
The instance is running. Stop the instance to take the snapshot.
What’s another term for Instance Store Volumes?
Ephemeral Storage
What happens to Instance Store Volumes if the host fails or stops?
The data is lost ; instance store volumes can’t be stopped. You can reboot them.
What happens to EBS-backed volumes if the host fails or stops?
The data is retained.
What’s a potential problem with snapshotting a RAID array?
The snapshot may be missing cached data, which can be a large issue with RAID.
What’s a good way to snapshot a RAID array?
Take an application consistent snapshot ; stop the application from writing to disk, and flush caches to disk by 1) freezing the file system, 2) unmounting the RAID array, or 3) shutting down the EC2 instance.
I created an AMI in eu-west-1, but I can’t see it in eu-central-1. Why not?
AMI’s are regional. You’ll need to copy the AMI using the console, command line, or API.
In Cloudwatch, what’s the interval for standard monitoring?
5 minutes
In Cloudwatch, what’s the interval for detailed monitoring?
1 minute
What are the main features of Cloudwatch?
Dashboards
Alarms
Events
Logs
When should you assign a role to an EC2 instance?
When creating ; you can only assign the role to an EC2 instance when you are creating it
Are roles regional?
No ; roles are universal.
What’s the IP address for local EC2 metadata?
169.254.169.254
What’s the curl command to display the instance metadata?
curl http://169.254.169.254/latest/meta-data
What protocol does EFS use?
NFSv4
How do you pay for EFS?
You pay only for the storage you use. 30c per GB.
What resiliency does EFS have?
EFS data is stored across multiple AZ’s, but only within the one region.
How do you pay for Lambda?
You pay only for the time your function runs, per 100ms slot,
How can Lambda be used?
To respond to events (AWS)
To respond to HTTP or API calls (external)
Can I delete a snapshot of an EBS Volume that is used as the root device of a registered AMI?
No, you must deregister the AMI before being able to delete the root device.
A placement group can be deployed across multiple Availability Zones.
False
What’s an EC2 placement group?
A placement group allows you to define several EC2 instances within their own high-speed, low-latency internal network. It is available within a single subnet and AZ only.
