November 20, 2021 | 193 Views
What is Amazon EC2?
The way Amazon EC2 works and how it can be implemented in place of traditional on-premises compute highlights why the cloud is so important in today’s world. Amazon EC2 as a service epitomizes the flexibility, durability, availability, and low barrier to entry you get when you use the cloud. Amazon EC2 strongly emphasizes why you should be utilizing the cloud for your business today.
Amazon EC2 is the Amazon Elastic Compute Cloud (EC2) – a compute service running on
Amazon Web Services (AWS). In short, Amazon EC2 is a Virtual Machine – which is nothing new. But what makes
Amazon EC2 special, is what it can provide in terms of scalability, flexibility and raw compute
power.
Offering secure, resizable compute capacity in the AWS cloud, Amazon EC2 has been designed by AWS to make
web-scale cloud computing easier for developers. Amazon EC2’s simple web service interface allows you to
obtain and configure capacity with minimal friction.
You get complete control of your computing resources, with the flexibility to use what you need, without
paying for unwanted compute. Flexibility means the ability to choose from hundreds of different instance
types depending on your use case, whether you want to host a simple website or whether you are performing
some extremely compute-intensive operations.
The power of Amazon EC2 is that you are given your own virtual machine in which you can do whatever you want
with, and the use cases are infinite.
The resizable nature also means that you are never under or over provisioning your resources, providing the
perfect balance between operational efficiency and cost optimization. EC2 also is part of the free tier, and
you can benefit from 750 hours of Linux and Windows t2.micro instances, ( t3.micro for the regions in which
t2.micro is unavailable) each month for one whole year!
There are a number of different things you can choose to configure when it comes to launching an EC2
instances, more than we can get into in one blog post in fact – but we will cover the main configuration
options of EC2.
When you launch your virtual machine, you get to configure each of the following options for the underlying
server (amongst many other settings):
- AMI (Amazon Machine Image)
- Instance Type
- Storage
- Security Group
What is an AMI?
An Amazon Machine Image (AMI) is basically a template that contains the software configuration (operating
system, application server, and applications) required to launch your instance. You can select an AMI
provided by AWS, the user community, or the AWS Marketplace; or you can select one of your own AMIs.
There are many different choices to get started, from the basic ‘Amazon Linux 2 AMI’ for a simple Linux
server all the way to deep learning AMIs and IoT AMIs on the AWS Marketplace.
What is an Instance Type?
Amazon EC2 provides a wide selection of instance types optimized to fit different use cases. Instances are
virtual servers that can run applications. They have varying combinations of CPU, memory, storage, and
networking capacity, and give you the flexibility to choose the appropriate mix of resources for your
applications.
These instance types are also in certain families, some of which are below:
- T2 – T2 instances are a low-cost, general purpose instance type that provides a baseline level of CPU performance with the ability to burst above the baseline when needed.
- C5 instances – C5 instances are optimized for compute-intensive workloads and deliver cost-effective high performance at a low price per compute ratio.
- P2 – P2 instances are intended for general-purpose GPU compute applications.
There are a number of different instance types, which will have different use cases depending on your budget and what type of EC2 instance you need to launch.
Storage
Your instance will be launched with an attached Amazon Elastic Block Store (Amazon EBS) volume. You can
attach additional Amazon EBS volumes and instance store volumes to your instance, or edit the settings of
the root volume. You can also attach additional EBS volumes after launching an instance, but not instance
store volumes.
You can choose the size of the volume in a GiB, as well as one of four storage types, namely;
- General Purpose SSD (gp2 and gp3)
- Provisioned IOPS (io1 and io2)
Security Groups
A security group is a set of firewall rules that control the traffic for your instance. On this page, you
can add rules to allow specific traffic to reach your instance. For example, if you want to set up a web
server and allow Internet traffic to reach your instance, add rules that allow unrestricted access to the
HTTP and HTTPS ports. You can create a new security group or select from an existing one below.
Even if you aren’t using the free tier there are many ways to configure your use of EC2 so that you can
ensure you are getting the best price and using only what you need to achieve performant
architecture.
The four different pricing options for EC2 are as follows;
- On-Demand
- Reserved Instances
- Spot Instances
- Saving Plans
On-Demand
On-Demand is what it sounds like. You pay for computing capacity by the hour (or a minimum of 60 seconds)
for as long as you need it, with the ability to start and stop your instance whenever you need to. You can
also change the compute capacity on the fly, allowing you to mirror the needs of your application
seamlessly. It is also the most costly pricing option when it comes to EC2.
There are some use cases in which On-Demand instances are perfect:
- Short term, spiky or unpredictable workloads
- Test and Dev environments
- The need to have no payment upfront
Reserved Instances
Reserved instances offer you a potential saving of up to 75% compared to On-Demand pricing. You basically
tell AWS that you want to use certain instances for a certain period of time, for either 1 or 3 years and
then you either pay all upfront, partial upfront or no upfront — with an all upfront 3-year plan providing
the biggest savings. You can also optionally have convertible reserved instances where you can change the
instance type as many times as you need to fulfill your needs.
The best use cases for reserved instances are:
- Steady-state applications
- Applications that require reserved capacity with long term use
Spot Instances
Spot instances are the cheapest option of all the payment options for EC2. You basically bid for unused EC2 capacity from AWS at a massive discount. However, the downside is that as soon as the bid price goes past your bid, AWS will reclaim the instances, meaning potential downtime for your application. Spot instances, therefore, are ideal for the following:
- Applications with flexible start and end time, e.g batch processing
- Applications that are only feasible at extremely low cost
- Spot instances can also be used in auto Scaling groups, as they will only be used temporarily when usage peaks for your application
Savings Plans
Savings Plans are a flexible pricing model that offers low prices on EC2, Fargate and Lambda – in exchange
for a commitment to a consistent amount of usage (measured in $/hour) for a 1 or 3-year term.
They may sound similar, but there are a few differences between Savings Plans and Reserved Instances.
Reserved Instances offer a discount against On-Demand pricing based on committed utilization, whereas
Savings Plans offer a discount based on committed spend.
A further difference between the AWS Compute Savings Plans and using Reserved Instances is that Savings
Plans not only to apply to the amount spent on EC2 Instances, but also to the amount spent on other compute
services too, namely AWS Fargate and Lambda.
Please note that this was just a brief introduction to EC2 because you could likely write an entire book on
this subject alone. I hope this has served as an informative introduction to what EC2 is, how it can be
used, and some of the pricing models it uses alongside all of the other aspects of EC2.