AWS Classroom Series – 27/Jan/2021

AWS Metrics Retention

  • Cloudwatch retains metrics data
    • Data points with period of less than 60 seconds (frequency) are available for 3 hours. These are called as high resolution metrics
    • Data points with period of 60 seconds are available for 15 days
    • Data points with period over 300 seconds are available for 63 days
    • Data points with period over 3600 seconds are available for 455 days

AWS Cloudwatch Terms

  • Dimensions: A dimension is a name/value pair that is part of identity of metric. Each metric can have upto 10 dimensions
  • General Dimensions added are
    • Environment = (Dev/QA/UAT/Prod)
    • Project = (name of project)
    • Version = (Version of the project)
  • Statistics:
    • Minimum
    • Maximum
    • Sum
    • Average
    • Sample Count
    • pNN.NN : percentile (p96.54)
  • Units: Each statistic has a unit of measure . Example units Bytes, Seconds, Percent etc
  • Period: frequency of data collection. Generally defined by number of seconds
  • Alarm: We use alarm to initiate some action automatically. Alarms can send notifications to SNS or Auto Scaling policy. Alarm can 3 values
    • Insufficient: Alarm doesnot sufficient data to decide
    • OK: Alarm is not met
    • Alarm: Your condition of alarm is met.

Lets play with Alarms

  • Scenario 1: Lets take a metric called as CPU Utilization (Percentage CPU) and when Percentage CPU is less than 40 lets shutdown the system.

  • Solution: Preview Preview Preview Preview Preview Preview

  • Scenario 2: Lets create an alarm to restart ec2 instance when Percentage CPU is grater than 90% for 5 mins

    • Lets login into ec2 instance and try to install a tool called stress
    sudo amazon-linux-extras install epel
    sudo yum install stress -y
    stress --cpu 8 -v --timeout 100m
    • Now watch for CPU Utilization Preview
    • Now create an alarm for above condition Preview Preview Preview Preview
  • Scenario 3: Create a cloudwatch alarm with no action to (Exercise)

    • Plot if the DB Connections are less than or equal to 10 in last 1 hour
    • Plot if the free space is less than 100 MB
  • Scenario 4: Send an email when cpu utilzation is grater than 80 % for 5 minutes Preview

  • Scenario 5: Send an email for underused ec2 instance (when cpu utilization is less than 30)

  • Scenario 6: Send an email for under used RDS instance (DB Connections equal to zero in last 1 hour)

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

About learningthoughtsadmin