EC2

Question 1

What are the 3 strategies available for Placement Groups?

Answer 1

• Cluster
• Spread
• Partition

Question 2

What is the Cluster Strategy?

Answer 2

It clusters instances into a low latency group in a single AZ - High performance but high risk

Question 3

What is the Spread Strategy?

Answer 3

It spreads instances across underlying hardware, with a max of 7 instances per AZ. - For critical apps

Question 4

Whats is the Partition Strategy?

Answer 4

Like Spread but relies on different sets of hardware racks in an AZ. Can scale to hundreds of EC2 instances per group and is good for Hadoop etc.

Question 5

What would I use a Cluster Placement Group for?

Answer 5

• Big Data job that needs to complete fast

- App that needs low latency and high network throughout

Question 6

What would I use a Spread Placement Group for?

Answer 6

• App that needs to maximize high availability

- Critical apps where instances need to be separated from each other

Question 7

What would I use a Partition Placement Group for?

Answer 7

HDFS, HBase, Cassandra, Kafka

Question 8

What happens if you have an instance that has termination protection enabled but shutdown behavior set to terminate?

Answer 8

If the shutdown command is run from the cli, the shutdown behavior will override the protections

Question 9

What does an InstanceLimitExceeded error mean?

Answer 9

You have reached the max number of instances allowed per region

Question 10

What is the default max number of instances per region?

Answer 10

20

Question 11

What does an InsuficcientInstanceCapacity error mean?

Answer 11

That AWS does not have the on-demand capacity in this region right now

Question 12

What are the 4 possible reasons an instance would terminate immediately? (go from pending to terminated)

Answer 12

• You’ve reached your EBS volume limit
• An EBS Snapshot is corrupt
• The root EBS volume is encrypted and you dont have permissions to access the KMS key for decryption
• The instance store backed AMI that you used is missing a required part.

Question 13

While SSH’ing into an instance, why would I get an “Unprotected Private Key File” error?

Answer 13

If the pem file does not have 400 permissions.

Question 14

While SSH’ing into an instance, why would I get an “Host key not found” error?

Answer 14

The incorrect username for the OS was given.

Question 15

What are the 2 possible reasons for a connection timeout while ssh into an instance?

Answer 15

• Security Group is not configured correctly

- CPU load of instance is too high

Question 16

What are the 11 EC2 instance types?

Answer 16

F - Field Programmable Gateway
I - IOPS
G - Graphics
H - High Disk Throughput
T - Cheap Genreal Purpose
D - Density
R - RAM
M - Main option for Genral Purpose
C - Compute
P - Graphics (pics)
X - Extreme Memory

Question 17

For Basic Monitoring in Cloudwatch, at what interval are metrics collected?

Answer 17

5 minute interval

Question 18

For Detailed Monitoring in Cloudwatch, at what interval are metrics collected?

Answer 18

1 minute interval

Question 19

What 4 metrics are included by default?

Answer 19

• CPU
• Network
• Disk
• Status Checks

Question 20

What is the basic resolution for a Custom Metric?

Answer 20

1 minute Resolution

Question 21

What is the high resolution for a Custom Metric?

Answer 21

Up to 1 second