Long pending issue / cause
On early 2010's, there were few users request about a use case where the console output was “Continue to wait; or Press S to skip mounting or M for manual recovery.”
Cause was due to the absence of interactive console feature to discover - "when boot failed, why SSH daemon did not start, errors configuring the firewall or network which blocked all access, broken networking on the instance, or denial-of-service attacks.
Alternative Solutions
There was an alternative solution by the system administrator. With an inaccessible EC2, it is possible to stop the instance, detach the storage, mount the storage on a working instance, and edit or recover the files from there. This is not always possible, though.
If VM uses instance type storage, this cannot be detached. It also requires interruption of service.
If a VM uses ephemeral storage, then the question is why do troubleshoot VM rather than simply deleting it and creating a new one?
When do we need?
Most AWS users never need this feature because SSH access does not often fail, and the range of use cases is relatively narrow. But, still, it is worth troubleshooting feature.
Generally Available
This month, AWS interactive EC2 Serial Console is generally available. EC2 Serial Console provides a simple and secure way to troubleshoot boot and network connectivity issues by establishing a connection to the serial port of an instance. This access can be used for interactive troubleshooting.
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