EC2 Troubleshooting:

Connectivity issues to an EC2 instance:

• Correct ports on the security group are may not be open.

Cannot attach an EBS volume to an EC2 instance:

• EBS volumes must live in the same availability zone as the EC2 instance they are to be attached to.

• You can create a snapshot from the volume and launch the volume in the correct availability zone.

Cannot launch additional instances:

• You have probably reached the EC2 limit and need to contact AWS to increase limit.

Unable to download package updates:

• The EC2 instance may not have a public/elastic IP address, and/or does not belong to a public subnet.

Applications seeming to slow down on T2 micro instances:

• T2 micro instances utilize CPU credits (for "bustable" processing), so chances are your application is using too much processing power and need a larger instance or different instance type.

AMI unavailable in other regions:

• AMIs are only available in the regions that they are created.

• An AMI can be copied to another region but will receive a new AMI id.

"Capacity error" when attempting to launch an instance in a placement group:

• Start and stop all the instances in the placement group (AWS ties to locate them as close as possible).