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2.0.1 : Linux Virtual Server | Heartbeat | Ldirectord | Installation | Topologies


Ldirectord

Ldirectord monitors the health of the real servers by periodically requesting a known URL and checking that the response contains an expected string. This is called a "negotiate" check. Ldirectord has support for performing a negotiate check for HTTP, HTTPS, FTP, IMAP, POP, SMTP, LDAP and NNTP servers. Adding negotiate check support for other protocols is usually quite simple. Ldirectord is also able to perform a simple check "connect" check for other servcies. The connect check simply verifies that the port on the real server is able to accept a connection.

If a real server fails then the server is made quiescent and will be reinserted once it comes back on line. If all the real servers are down then a fall-back server is inserted into the pool, which will be made quiescent one of the real web servers comes back on line. Typically, the fall-back server is localhost. If an HTTP virtual service is being provided then it is useful to run an Apache HTTP server that returns a page indicating that the service is temporarily inaccessible.


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Last Updated: Tue May 17 17:37:25 2005 +0900

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