Hi Mathias, Maybe you could contribute some docs, you seem very familiar with the subject ! Code would be even better :-)
In jk2 it should be possible for 'callbacks' to change anything, and all the information about lb is exposed in accessible structures ( private data has been greatly reduced ). That means a tomcat that takes over for a falled one could ( during the negotiation phase ) add a mapping ( probably we need a 'redirect' table in uriMap ). BTW, one thing that we should add is 'greacefull shutdown' - that will also be done ( probably ) using a callback ( i.e. have only sticky requests forwarded to a tomcat instance ). Costin On Tue, 18 Dec 2001, Mathias Herberts wrote: > Hi, I have been working on load balancing Apache/Tomcat clusters. > > In mod_jk, the fail-over is done in the function > get_most_suitable_worker. Basically if the worker who initiated the > session is available (i.e. not in error state), use it, otherwise loop > through the workers and select either the one with the lowest load > balancing value OR one that has been in error for at least > WAIT_BEFORE_RECOVER seconds if such worker exists. Thus the faulted > workers are privileged when selecting a worker for a request whose > worker designated by the jvmroute is not available. > > There is though no algorithm implemented which will map all requests to > the same 'backup' worker, thus either the worker which created the > session (the one in the jvmroute) is available, either another worker > will be selected, but in the latter case there is no guarantee that > 'second choice' will be the same for the next requests. > > Therefore re-routing does exist in mod_jk and works, but it is not > optimal for your case, the worst thing being the > dispatching of incoming requests to a different worker each time, your > distributed session management would therefore give the parenting of the > session to a different worker each time, far from optimal! > > Mathias. > > -- > To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> > -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
