In this post, you can learn about Amazon EC2 instance that means if you are preparing for AWS certification then this information can be useful for you. These 10 things can help you know about AWS more better.
Amazon EC2 Instance
Amazon EC2 Instance stands for Amazon Elastic Compute Cloud. It is basically a web service that provides you with resizable computing capacity in the cloud. In short, it reduces the time required for obtaining and booting new server instances to minutes which makes it easy to use feature and allowing you to quickly scale the capacity, both up and down, as your computing requirements change.
Therefore, as compared to the time when you have to create your own server yourself which used to take sometime even days on getting the information on how much the CPUs is needed, how much RAM is needed, how much disk storage you needed. Then, you had to purchase all the requirements which costs you some investment, it would then arrive to your place then you will rack it. So, it takes a lot of time to scale your compute capacity traditionally. But now, the public cloud made it easy to create your server instance and scale it both up and down to minutes and it has a pay as you go feature which enables you to pay only for your usage.
Following are some points you should know about EC2 Instances:
1. ENI stands for Elastic Network Interface
ENI is a virtual network interface which are only available for instances in your VPC (Virtual Private Cloud) that means you can attach network interfaces only to the instances running in VPC. It can include the attributes like; One primary private IPv4 address, one or more secondary private IPv4 addresses, one Elastic IP address per private IPv4 address, a MAC address, one or more security groups etc.
2. A single AWS account is limited to 20 On-Demand or Reserved instances and 20 spot instances with some additional limitations on large instance types
On-Demand instances – It allow you to pay a fixed rate by the hour with no commitment.
Reserved instances – It provides you with capacity reservation and offers a significant discount on the hourly charge for an instance.
Spot instances – It enables you to bid whatever price you want for instance capacity and if your application have flexible start and end times then you can have great additional savings.
3. Partial instance-hours cost as much as one full hour
You pay for the compute capacity by the hour that means if your instance is running it will be charged by the hour unless it is is stopped or terminated. Partial instance-hours are calculated as one full hour so it costs you as much as one full hour.
4. AMI stands for Amazon Machine Images
AMI is a template that contains a software configuration (for example, an operating system, an application server, and applications). You can choose any of the AMIs in which you are comfortable working on like Amazon Linux, Windows Server, Ubuntu, RedHat etc.
5. By default, you can assign 5 Elastic IP addresses to an AWS account
You can assign a maximum of 5 Elastic IPs to an AWS account by default. Elastic IPs are the static public IP addresses designed for dynamic cloud computing which can be used to connect to your instance from your local computer anytime even if the instance is stopped and then start, your elastic ip won’t change.
6. Tags are used to categorize a set of instances
Owner of an AWS account use Tags to categorize a set of Amazon EC2 instances.
7. Which of the following services is used to monitor the Amazon Web Services resources?
- AWS Monitor
- AWS CloudWatch
- AWS EC2
- AWS CloudFront
AWS CloudWatch is a service which is used to monitor the Amazon Web Services resources. It can be used to collect and track metrics, set alarms, monitor log files and can also monitor resources like Amazon EC2, Amazon RDS, Amazon DynamoDB Instance etc.
8. Common points of failures are not shared across Availability Zones
Common points of failures like generators and cooling equipments are not shared across Availability Zones. You can say that they are physically separate; such that the uncommon disastres like fires, tornados would only affect a single Availability Zone.
9. How can an instance be carried to another region
An instance can be carried to another region by creating an AMI and copying it to another region. When you first copy an instance store-backed AMIs to a region, AWS create an S3 bucket for the AMIs copied to that region and store in the bucket.
10. Provisioned IOPS can be to improve IOPS performance
For Example, you are running a database on an m1.small instance and customers have performance issues. After investigation, the database administrator asks you to improve IOPS performance. So, Provisioned IOPS can be used to improve IOPS.