Chapter 6 - Elastic Compute Cloud (EC2)

Question 1

EC2

Answer 1

1. 1 of the most fundamental services of AWS
2. EC2 just stands for Elastic Compute Cloud
3. This is basically secure, resizable compute capacity in the cloud.
4. So it’s just a virtual server that sits in the cloud, hosted on AWS
5. Designed to make web-scale cloud computing easier for developers
6. But essentially what it does is it gives you the capacity that you want when you need it.
7. You’re in complete control of your own instances.
8. It’s not managed by AWS.
9. You only pay for what you use
10. You can select the capacity that you need right now, and you can grow and shrink your servers as you go.

Question 2

EC2 - 4 fundamental ones

Answer 2

1. On-Demand - This is where you pay by the hour or second depending on the type of instance you run.
2. Reserved Capacity - This is where you, essentially, you get into a contract with AWS for between 1 to 3 years.
3. The longer the contract and the more you pay upfront the greater discount you get.
4. Spot - this is where you purchase unused capacity at a discount of up to 90% of prices,but prices fluctuate with supply and demand.
5. So with spot prices, basically the price of your EC2 instance moves up and down sort of like the way a share price moves up and down.
6. Dedicated - this is more expensive. This is where you have a physical EC2 server that’s dedicated for your use. It is the most expensive option

Question 3

EC2 Usage Instances

Answer 3

On-Demand instance - This is used where you need flexibility.

• So if you need the low cost and flexibility of EC2 without any upfront payment or long-term commitment.
• Typical use case so this is where you’re building a site from scratch, and you just want to see what the application looks like, and you’re coding it for the very first time.
• It’s also good and useful for short term.
• So applications with short term or spiky or unpredictable workloads that can’t be interrupted.

Reserved Instances - Essentially it’s the opposite of that.

• So it’s where you’ve got predictable usage.
• This is where you understand the usage patterns of your applications, and it’s a steady state predictability behind it. It’s also where you’ve got specific capacity requirements.
• It’s also very useful way you can afford to pay upfront maybe you’ve gone out and gotten VC funding,
• so you’re able to burn some cash for a couple of years.
• You can make some upfront payments to reduce the total computing costs even further.

Convertible Reserved Instances.

• So these are similar to Standard Reserved Instances except you have the option to change to a different reserved instance type with equal or greater value.
• You have compute-based EC2 instances.
• You might have GPU-based EC2 instances.
• And the cool thing about Convertible Reserved Instances, it allows you to change between the different classes of EC2 instances.

Scheduled Reserved Instances

• They basically allow you to launch within the time window that you find, so you can match your capacity reservation to a predictable recurring schedule that only requiresa fraction of the day, week, or month.
• They operate at a regional level.

Question 4

EC2 - Exam Tips

Answer 4

• EC2 is basically like a virtual machine.
• It’s hosted in AWS instead of your own data center.
• You can select the capacity that you need right now.
• You can grow and shrink it when you need it.
• You only pay for what you use
• You only have to wait minutes for an EC2 instance to provision.
• • 4 different pricing models.

1. On-Demand - This is where you pay by the hour or the second depending on the type of instance that you want to run.It’s great for flexibility.
2. Reserved - This is where you’ve got reserved capacity for 1 or 3 years, you get up to 72% of the discount on the hourly charge. This is great if you’ve got no unfixed requirements such as you need these dedicated web servers or dedicated database servers.
3. Spot - This is where you’re purchasing unused capacity of a discount up to 90%. But the price moves around all the time with supply and demand. So this is where you’ve got applications with flexible start and end times.
4. Dedicated Instances - and this will be where you’ve got compliance or licensing regulations to meet. So it’s still a physical EC2 instance. You’re not sharing it with anybody else. And like I said, it’s where you’ve got compliance and licensing base requirements.