Ec2 1/2 checks passed

The status checks automatically performed on Amazon EC2 instances are:

• System Status Checks: These check the underlying systems used by the Amazon EC2 instance
• Instance Status Checks: These check the configuration of the specific instance

See documentation: Status Checks for Your Instances

Often, an instance is available and ready to be used before these checks are complete -- this is especially the case for Linux instances because they boot very quickly.

If you receive a 1/2 checks passed message, either wait a little longer or Stop and Start the instance. Performing a Stop/Start will launch the instance on a different host, which will probably fix whatever problem was being experienced.

If the 1/2 checks passed message continues to appear after a Stop/Start, it is probably a misconfiguration of the AMI. I have seen this when the wrong virtualization type was selected for an AMI that was created from a Snapshot.

You might be able to get a hint about the problem by using the Get System Log command in the Actions menu, which shows the log while the instance is booting.

Worst case, launch a new instance from a known-good AMI, attach the non-booting volume as an additional disk and copy files to the new disk. You will still have access to your files even if it will not boot.

You can check the description of the checks here, and understand which one is not working...