AWS - Elastic Compute Cloud

---

Amazon EC2 (Elastic Compute Cloud) is a web service interface that provides resizable compute capacity in the AWS cloud. It is designed for developers to have complete control over web-scaling and computing resources.

EC2 instances can be resized and the number of instances scaled up or down as per our requirement. These instances can be launched in one or more geographical locations or regions, and Availability Zones (AZs). Each region comprises of several AZs at distinct locations, connected by low latency networks in the same region.

EC2 Components

In AWS EC2, the users must be aware about the EC2 components, their operating systems support, security measures, pricing structures, etc.

Operating System Support

Amazon EC2 supports multiple OS in which we need to pay additional licensing fees like: Red Hat Enterprise, SUSE Enterprise and Oracle Enterprise Linux, UNIX, Windows Server, etc. These OS needs to be implemented in conjunction with Amazon Virtual Private Cloud (VPC).

Security

Users have complete control over the visibility of their AWS account. In AWS EC2, the security systems allow create groups and place running instances into it as per the requirement. You can specify the groups with which other groups may communicate, as well as the groups with which IP subnets on the Internet may talk.

Pricing

AWS offers a variety of pricing options, depending on the type of resources, types of applications and database. It allows the users to configure their resources and compute the charges accordingly.

Fault tolerance

Amazon EC2 allows the users to access its resources to design fault-tolerant applications. EC2 also comprises geographic regions and isolated locations known as availability zones for fault tolerance and stability. It doesn’t share the exact locations of regional data centers for security reasons.

When the users launch an instance, they must select an AMI that's in the same region where the instance will run. Instances are distributed across multiple availability zones to provide continuous services in failures, and Elastic IP (EIPs) addresses are used to quickly map failed instance addresses to concurrent running instances in other zones to avoid delay in services.

Migration

This service allows the users to move existing applications into EC2. It costs $80.00 per storage device and $2.49 per hour for data loading. This service suits those users having large amount of data to move.

Features of EC2

Here is a list of some of the prominent features of EC2 −

• Reliable − Amazon EC2 offers a highly reliable environment where replacement of instances is rapidly possible. Service Level Agreement commitment is 99.9% availability for each Amazon EC2 region.

• Designed for Amazon Web Services − Amazon EC2 works fine with Amazon services like Amazon S3, Amazon RDS, Amazon DynamoDB, and Amazon SQS. It provides a complete solution for computing, query processing, and storage across a wide range of applications.

• Secure − Amazon EC2 works in Amazon Virtual Private Cloud to provide a secure and robust network to resources.

• Flexible Tools − Amazon EC2 provides the tools for developers and system administrators to build failure applications and isolate themselves from common failure situations.

• Inexpensive − Amazon EC2 wants us to pay only for the resources that we use. It includes multiple purchase plans such as On-Demand Instances, Reserved Instances, Spot Instances, etc. which we can choose as per our requirement.

How to Use AWS EC2

Step 1 − Sign-in to AWS account and open IAM console by using the following link https://console.aws.amazon.com/iam/.

Step 2 − In the navigation Panel, create/view groups and follow the instructions.

Step 3 − Create IAM user. Choose users in the navigation pane. Then create new users and add users to the groups.

Step 4 − Create a Virtual Private Cloud using the following instructions.

• Open the Amazon VPC console by using the following link − https://console.aws.amazon.com/vpc/

• Select VPC from the navigation panel. Then select the same region in which we have created key-pair.

• Select start VPC wizard on VPC dashboard.

• Select VPC configuration page and make sure that VPC with single subnet is selected. The choose Select.

• VPC with a single public subnet page will open. Enter the VPC name in the name field and leave other configurations as default.

• Select create VPC, then select Ok.

Step 5 − Create WebServerSG security groups and add rules using the following instructions.

• On the VPC console, select Security groups in the navigation panel.

• Select create security group and fill the required details like group name, name tag, etc.

• Select your VPC ID from the menu. Then select yes, create button.

• Now a group is created. Select the edit option in the inbound rules tab to create rules.

Step 6 − Launch EC2 instance into VPC using the following instructions.

• Open EC2 console by using the following link − https://console.aws.amazon.com/ec2/

• Select launch instance option in the dashboard.

• A new page will open. Choose Instance Type and provide the configuration. Then select Next: Configure Instance Details.

• A new page will open. Select VPC from the network list. Select subnet from the subnet list and leave the other settings as default.

• Click Next until the Tag Instances page appears.

Step 7 − On the Tag Instances page, provide a tag with a name to the instances. Select Next: Configure Security Group.

Step 8 − On the Configure Security Group page, choose the Select an existing security group option. Select the WebServerSG group that we created previously, and then choose Review and Launch.

Step 9 − Check Instance details on Review Instance Launch page then click the Launch button.

Step 10 − A pop up dialog box will open. Select an existing key pair or create a new key pair. Then select the acknowledgement check box and click the Launch Instances button.

Amazon Web Services - Auto Scaling

---

As the name suggests, auto scaling allows you to scale your Amazon EC2 instances up or down automatically as per the instructions set by the user. Parameters like minimum and maximum number of instances are set by the user. Using this, the number of Amazon EC2 instances you’re using increases automatically as the demand rises to maintain the performance, and decreases automatically as the demand decreases to minimize the cost.

Auto Scaling is particularly effective for those applications that fluctuate on hourly, daily, or weekly usage. Auto Scaling is enabled by Amazon CloudWatch and is available at no extra cost. AWS CloudWatch can be used to measure CPU utilization, network traffic, etc.

Elastic Load Balancing

Elastic Load Balancing (ELB) automatically distributes incoming request traffic across multiple Amazon EC2 instances and results in achieving higher fault tolerance. It detects unfit instances and automatically reroutes traffic to fit instances until the unfit instances have been restored in a round-robin manner. However, if we need more complex routing algorithms, then choose other services like Amazon Route53.

ELB consists of the following three components.

Load Balancer

This includes monitoring and handling the requests incoming through the Internet/intranet and distributes them to EC2 instances registered with it.

Control Service

This includes automatically scaling of handling capacity in response to incoming traffic by adding and removing load balancers as required. It also performs fitness check of instances.

SSL Termination

ELB provides SSL termination that saves precious CPU cycles, encoding and decoding SSL within your EC2 instances attached to the ELB. An X.509 certificate is required to be configured within the ELB. This SSL connection in the EC2 instance is optional, we can also terminate it.

Features of ELB

Following are the most prominent features of ELB −

• ELS is designed to handle unlimited requests per second with gradually increasing load pattern.

• We can configure EC2 instances and load balancers to accept traffic.

• We can add/remove load balancers as per requirement without affecting the overall flow of information.

• It is not designed to handle sudden increase in requests like online exams, online trading, etc.

• Customers can enable Elastic Load Balancing within a single Availability Zone or across multiple zones for even more consistent application performance.

How to Create Load Balancers?

Step 1 − Go to Amazon EC2 console using this link − https://console.aws.amazon.com/ec2/.

Step 2 − Select your load balancer region from the region menu on the right side.

Step 3 − Select Load Balancers from the navigation pane and choose Create Load Balancer option. A pop-up window will open and we need to provide the required details.

Step 4 − In load Balancer name box: Enter name of your load balancer.

Step 5 − In create LB inside box: Select the same network which you have selected for instances.

Step 6 − Select Enable advanced VPC configuration, if selected default VPC.

Step 7 − Click the Add button and a new pop-up will appear to select subnets from the list of available subnets as shown in the following screenshot. Select only one subnet per availability zone. This window will not appear if we do not select Enable advanced VPC configuration.

Step 8 − Choose Next; a pop-up window will open. After selecting a VPC as your network, assign security groups to Load Balancers.

Step 9 − Follow the instructions to assign security groups to load balancers and click Next.

Step 10 − A new pop-up will open having health checkup configuration details with default values. Values can be set on our own, however these are optional. Click on Next: Add EC2 Instances.

Step 11 − A pop-up window will open having information about instances like registered instances, add instances to load balancers by selecting ADD EC2 Instance option and fill the information required. Click Add Tags.

Step 12 − Adding tags to your load balancer is optional. To add tags click the Add Tags Page and fill the details such as key, value to the tag. Then choose Create Tag option. Click Review and Create button.

A review page opens on which we can verify the setting. We can even change the settings by choosing the edit link.

Step 13 − Click Create to create your load balancer and then click the Close button.

How to Delete a Load Balancer?

Step 1 − Go to Amazon EC2 console using this link − https://console.aws.amazon.com/ec2/.

Step 2 − Choose Load Balancers option from the navigation pane.

Step 3 − Select Load balancer and click the Action button.

Step 4 − Click the Delete button. An alert window will appear, click the Yes, Delete button.