Книга: Distributed operating systems

7.6.5. The Boot Server

7.6.5. The Boot Server

As another example of an Amoeba server, let us consider the boot server. The boot server is used to provide a degree of fault tolerance to Amoeba by checking that all servers that are supposed to be running are in fact running, and taking corrective action when they are not. A server that is interested in surviving crashes can be included in the boot server's configuration file. Each entry tells how often the boot server should poll and how it should poll. As long as the server responds correctly, the boot server takes no further action.

However, if the server should fail to respond after a specified number of attempts, the boot server declares it dead, and attempts to restart it. If that fails, t arranges to allocate a new pool processor on which a new copy is started. In his manner, critical services are rebooted automatically if they should ever fail. The boot server can itself be replicated, to guard against its own failure.

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