EC2

Question 1

On Demand Instance

Answer 1

Pay by the hour or second, depending on the type of instance you run. Great for flexibility with no long term contract

Question 2

Spot instance

Answer 2

Purchase unused capacity at discount of up to 90% Prices fluctuate with supply and demand

Question 3

Reserved Instances

Answer 3

Reserved capacity for 1-3 years up to 72% discount on the hourly charge. Great if you have known fixed requirements.

Question 4

Dedicated Hosts

Answer 4

A physical EC2 server dedicated for your use. Great if you have a server bound license to reuse or for compliance, no multi tenancy

Question 5

Things to keep in mind for the AWS command line

Answer 5

Use principle or least privilege

Use IAM groups, & assign your users to them. Group permissions are assigned using IAM policy docs. Your users will automatically inherit the permissions of the group

Question 6

3 Important tips for AWS CLI

Answer 6

1. Use secret key access. Keep in mind you only see this key once so save it!
2. Don’t share key pairs
3. Can install the AWS cli on windows, Linux, and max as well as on EC2 servers

Question 7

Roles

Answer 7

Preferred from a security perspective

Helps avoid hard coding credentials

Policies control a roles permission

Updating a policy attached to a role will take immediate effect

You can attach and detach roles on running ec2 instances without needing to take them down

Question 8

Security Groups

Answer 8

1. Changes to security groups take immediate effect
2. You can have any # of EC2 instances in a security group
3. You can have multiple security groups attached to ec2 instances

4 all inbound traffic is blocked by default

5. All outbound traffic is allowed

Question 9

Bootstrap Scripts

Answer 9

A bootstrap script is a script that runs when the instance first starts.

It passes user data to the instance & can be used to install apps (eg Apache or a db), as well as do updates & more

Question 10

User Data

Answer 10

User data is just a boot strap script

Question 11

EC2 Metadata

Answer 11

Data about your instance, you can use user data to access metadata

Question 12

EC2 ENI

Answer 12

For basic networking.

Perhaps you need to separate your management network from prod, or separate a logging network & you need it at a low cost.

In this scenario use multiple ENIs for each EC2 instance

Question 13

EC2 Advanced Networking

Answer 13

For when you need speeds between 10gbps and 100 gbps. Anywhere you need reliable high throughput

Question 14

EC2 EFA

Answer 14

For when you need to accelerate high performance computing (hpc) & machine learning apps or if you need to do an ops bypass.

If you see a scenario question mentioning hpc or ml and asking what network adapter you want efa

Question 15

Cluster Placement Groups

Answer 15

Low network latency, high network throughput

Question 16

Spread Placement Groups

Answer 16

Individual Critical EC2 instances

Question 17

Partition Placement Groups

Answer 17

Multiple EC2 instances, HDFS, Hbase, & Cassandra

Spreads instances across logical partitions such that groups of instances in one partition don’t share underlying hardware with groups of instances in different partitions.

Typically used by large distributed replicated workloads like Hadoop, Cassandra, and Kafka

Question 18

What is an EC2 Placement Group?

Answer 18

Placement groups are just logical groupings for EC2 instances

Question 19

What are the important things to know about a placement group?

Answer 19

A cluster group can’t span AZs but a spread or partition placement group can

Only certain types of instances can be launched into a placement group (cpu, memory or storage optimized)

You can’t merge placement groups

You can move an existing instance into or out of a placement group. It must be in a stopped state and it can only be done using CLI or SDK

Question 20

Dedicated Hosts

Answer 20

Any question talking about specific licensing requirements

Allows use of existing per socket, per core, or per VM software licensing

Including Windows server, my sql, Susie Linux enterprise, etc

Question 21

What is a spot fleet

Answer 21

A spot fleet is a collection of spot instances & optionally on-demand instances

You can use block spot instances from terminating using spot block