Auto Scaling in AWS

Auto Scaling

AWS provides multiple services that you can use to scale your application. Auto scaling is enabled by Amazon CloudWatch and is available at no additional charge beyond the service fees for CloudWatch and the other AWS resources that you use.

  1. What is Auto Scaling?
  2. Befits of Auto Scaling
  3. Experience Auto Scaling
    Step 1: Create load balancer.
    Step 2: Create Launch configuration  
    Step 3: Create Topic in SNS ( Simple Notification Service )
    Step 4: Create Auto scaling group.
    Step 5: Create Alarm in CloudWatch
    Step 6: Add Policy in Auto Scaling
    

1. What is Auto Scaling?

AWS Auto Scaling is a service that helps the user to monitor applications and automatically adjusts the capacity to maintain steady, predictable performance at the lowest possible cost.

Auto Scaling helps you ensure that you have the correct number of EC2 instances available to handle the load for your application.

2. Befits of Auto Scaling

  • Better fault tolerance
  • High availability of resources
  • Better cost management
  • High reliability of resources
  • The high flexibility of resources

3. Understanding Launch Configuration .

Step 1: Create load balancer

 Select Mumbai location
 EC 2 dashboard =>  load balancer =>  create load balancer
 Load balancer Name => LB
 Next => Create new Security group 
 Security group name => LB_Sg
 Description => LB_Sg
 => in Security group open two ports   SSH  and HTTP
 =>Next => Configure health check
Response timeout => 2
Interval => 5
Unhealthy  threshold => 2
Healthy threshold  => 2
Next => Next => Review and create => Create => Close

Step 2: Creating launch configuration

Under Auto Scaling Select Launch configurations => Create launch configuration Name: ASG =>AMI => ami-08e0ca9924195beba => t2 micro

In advanced Details User data

 #!/bin/bash
 sudo su
 yum update -y
 yum install httpd -y
cd /var/www/html
echo "MyGoogle_page2" > index.html
service httpd start
chkconfig httpd on

Next => Select existing security group : LB_Sg Create new key pair => Key Pair name => KP => download key pair => create launch configuration.

Step 3: Create Topic in SNS

 Services => Application Integration => Simple Notification Service 
 Create Topic = >Type - Standard => Name - My_Topic
 Display Name - My_Topic =>Create topic.

Add subscriptions to the topic

 Create Subscription  => Protocol - Email  =>Endpoint =>  Your Email => Create 
 Subscription => Confirm the subscription.

Step 4: Create Auto Scaling Group

 Select the Launch Configuration => Actions => Create Auto Scaling Group
  - Auto Scaling group name=> ASG
  - Subnet => ap-south-1a
  - Attach Existing Load Balancer => Choose from Classic Load Balancers 
      => Select Load Balancer
  - Configure Group size ( Take Defaults ) =>Next => Next => Provide Name Tag => 
     Review and Create

Step 5: Create Alarm in CloudWatch

Services => Management & Governance => CloudWatch

  Alarm =>  Create Alarm => Select Metric => EC2 => By Auto Scaling Group 
   => Select Auto Scaling Group Name  , Metric Name - CPU Utilization => Select Metric 
   => Conditions 
   => Static => Greater than > 80 => Next => Select  existing 
       SNS topic ( My_Topic ) =>Next =>Alarm Name(My_Alarm) => Next => Create Alarm.

  Alarm =>  Create Alarm => Select Metric => EC2 => By Auto Scaling Group 
  => Select Auto Scaling Group Name  , Metric Name - CPU Utilization 
  => Select Metric => Conditions 
  => Static => less than < 30 => Next => Select  existing SNS 
       topic ( My_Topic) =>Next =>Alarm Name(My_Alarm2) => Next => Create Alarm.

Step 6: Add Policy in Auto Scaling

Select Auto Scaling groups => Automatic Scaling Tab => Creating Dynamic scaling Policy
Policy Type => Simple Scaling
Scaling policy name => Increase_Policy 
CloudWatch Alarm=> My_alarm
Take the Action => Add => 1  Unit ( EC2 Machine ) =>Create

Select Auto Scaling groups => Automatic Scaling Tab => Creating Dynamic scaling Policy
Policy Type => Simple Scaling
Scaling policy name => Decrease_Policy
CloudWatch Alarm => My_alarm2
Take the Action => Remove => 1  Unit ( EC2 Machine ) => Create

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ALa Al-Din Al-Sharabi
ALa Al-Din Al-Sharabi