EC2 Flashcards
Instance pricing models
On Demand, Spot, Reserved, Dedicated Hosts
If you terminate spot instance
you pay for the hour. If AWS terminates it, you are not charged for the hour
Instance types
DRMCGIFTPX
EBS types
SSD, General Purpose - GP2 (up to 10k IOPS) SSD, Provisioned IOPS - IO1 (> 10k IOPS) HDD, Throughput Optimized - ST1 (frequently accessed workloads) HDD, Cold - SC1 (less frequently accessed data) HDD, Magnetic Standard (cheap, infrequently accessed storage)
Can you mount 1 EBS volume to multiple EC2 instances?
No, use EFS instead
Termination protection default?
is turned off by default, you must turn it on
On an EBS-backed instance, the default action is for the root EBS volume to be what if instance is terminated?
to be deleted when the instance is terminated
Can root volumes be encrypted by default?
No, you need a third party tool to encrypt the volume. Additional volumes can be encrypted
Volumes exist on
EBS. virtual hard disk
Snapshots exist on
S3
Can you take a snapshot of a volume?
Yes, this will store that volume on S3
What are snapshots?
point in time copies of Volumes
Snapshots are incremental, so
only the blocks that have changed since your last snapshot are moved to S3
First snapshots
may take some time to create
Snapshots of encrypted volumes
are encrypted automatically
Volumes restored from encrypted snapshots
are encrypted automatically
Can you share snapshots?
Yes if they are unencrypted. these snapshots can be shared with other AWS accounts or made public
to create a snapshot for EBS volumes that serve as root devices,
you should stop the instance before taking the snapshot
Instance store volumes are sometimes called
ephemeral storage
Can instance store volumes be stopped?
No, if the underlying host fails, you will lose your data
Can EBS volumes be stopped?
Yes, you will not lose data if it is stopped
Can you reboot volumes?
Yes for both, you will not lose data
By default, both root volumes will be what at termination?
will be deleted on termination, but you can tell AWS to keep the root EBS volume
How to take snapshot of a raid array?
take application consistent snapshot to prevent excluding data. stop the app from writing to the disk + flush all caches to the disk. freeze file system or unmount raid array or shut down associated instance