Programming Amazon Web Services

Console Output and Instance Reboot

The final two EC2 API actions could be invaluable when you have an instance that is not working as expected and you need to troubleshoot the problem. Although you have complete control over the life cycle of your EC2 instances, this control will not help much if an instance fails to start correctly and leaves you unable to log in via a secure session. The console output and instance rebooting operations described in this section provide a means to debug instance start-up problems and to restart instances on demand.

Console Output Snapshot

The GetConsoleOutput operation shown in Table 5-33 provides a mechanism for instance owners to view the console output generated by their instance's operating system, much as it would appear on a monitor screen if the instance was actually connected to one. The console log information available through this service is not intended to provide all console output in real time, and it has some key limitations that make it unsuitable as a replacement for a proper login account for instance monitoring; however, it could help in situations where it is not possible to log in to your instance.

The main limitations of the GetConsoleOutput action are:

• The console log is not constantly updated. The information is only refreshed after major instance life-cycle events, such as when the instance boots up, is rebooted, or is terminated.

• The log displays only the last 64 KB of output.

• The log is not stored permanently and will not ...