AWS EC2 Instances

EC2 Instances:

  1. On-demand instances
  2. Reserved instances
  3. Spot instances
  4. Dedicated hosts
  5. Scheduled instances

On-demand instances:

  • These instances are chanrged per hour basis.
  • When instances are not running, there are no charges.
  • Even if instance is stopped, bill counts for EBS volumes attached to the instance.
  • Use this instance type when we need instances for short duration (1 day, 1week, one month.

Reserved Instances:

  • We can reserve instances either one or three years.
  • The advantage of reserved instance is we can save up to 70% of the cost when compared with ondemand instances
  • Once reserved purchase is done, there is no option to terminate the contract, only option is to sell it over AWS marketplace
  • Reserved instance payment options: All upfront, Partial upfront and no upfront.
  • AWS billing automatically applies discovered rates when you launch an instance that matches your purchanges RI.
  • EC2 Reserved instance has three types.
  •  1. Standard
  •  2. Convertible
  •  3.
  • RI’s can be shared across multiple accounts with in consolidated billing.

Spot Instances:

  • Amazon EC2 spot instances allow you to bid on spare Amazon EC2 computing capacity for up to 90% off the on-demand price
  • Spot instances are excess EC2 capacity that AWS tries to sell on an market exchange basis.
  • Customer defines highest willing to pay for instance. If capacity is constrained and others are willing to pay more, your instance might get terminated or stopped.
  • For “one time request”, instance is terminated and ephermal data is lost.
  • For “reqeust and maintain”, instance can be configured to terminate, hybernate or stop until price point can be met again.

Dedicated Hosts:

  • A dedicated host is a phsyical EC2 server dedicated to your use.
  • Dedicated hosts can help you reduce costs by allowing you to use your existing server-boud software license, including windows server, SQL server, SUSE linux etc.

Scheduled instances:

  • We can buy instances based on your schedule.
  • Example: if you need servers on daily, weekly, monthly basis and in dedicated hours for example: 4 to 5 hours per day, then you can go for scheduled instances.





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