Elastic Network Inferfaces are logical components in your AWS Virtual Private Cloud which present Virtual Network Cards.  ENI can be created independently of EC2 Instances and can be assigned at any time on the fly and moved from one instance to another.  Each ENI has the options of:

        1.  One primary private IPv4 address and can have one or more secondary private IPv4 addresses

        2.  One Elastic IP address per private IPv4.

        3.  One Public IPv4 address

        4.  One or more security groups

        5.  A MAC address

        6.  ENI are bound to one availability zone.

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1.  Logon to AWS as an IAM user at URL:  https://signin.aws.amazon.com/

2.  From the Home Console type EC2 in the search bar, select the star next to EC2, and select EC2

3.  On the let hand menu bar select Network Interfaces.

4.  The page will display all currently existing ENI, we currently have created two EC2 Instances and AWS created two ENI for them by default.   Select Create network interface.

5.  Under details, enter the description of your network card, the subnet, Interface type, and Auto-assign of IP address.

6.  In the security groups section, select an existing group and enter a Tag if desired.  Click the Crete network interface to proceed.

7.  The creation will be confirmed on the next page.

8.  You can modify, associate, or delete the ENI by clicking on the ENI of choice and select Actions.

AWS placement groups allow you to have control over EC2 Instance physical layout in relationship to each other.   A good example of this would be a Cluster configuration were you are attempting to share the workload among multiple EC2 Instance.  Placement groups can be designed in one of three ways:

Cluster – Configured into low-latency group within a single Availability Zone.

        1.  Great network performance, but if AZ fails all fails

        2.  Big Data jobs, Applications requiring extremely low latency are examples

Spread – Spreads Instance across underlying hardware.  This is limited to 7 Instance per Placement Group per Availability Zone.    It is intended for Critical applications.

        1.  Minimize loss – Very low risk of failure.

        2.  Can span multiple AZ and EC2 Instances are on different physical hardware

        3.  Limited growth – only 7 Instances

        4.  Maximum availability of applications and Critical Applications where you need failures to   be isolated.

Partition – Spreads Instances across many partitions on different sets of rack within one Availability Zone.  Can Scale to 100s of EC instance per placement group.

   -An Active AWS Account with admin level permissions.

                -Multiple EC2 Instances

2.  Logon to AWS as an IAM user at URL:  https://signin.aws.amazon.com/

3.  From the Home Console type EC2 in the search bar, select the star next to EC2, and select EC2

4.  On the left hand menu bar select Placement Groups.

5.  Currently we have no placement groups, select Create placement group

6.  On the Name the placement group, select Cluster, Spread, or Partition, and spread level or number of partition options you desire.  Press Create group to proceed.

7.  During the creation of EC2 Instances you can select the partition group as an option for deployment of new EC2 Instances.