Linux for IBM eServer zSeries and S/390: Distributions

Chapter 18. High Availability using clusters 333

One odd result we experienced was that the tunnel devices really didn’t need to

be defined in the Linux director. In our case, with the tunl0 device iconfiged in the

real servers and the services defined to ipvsadm as tunneling, everything

worked. We don’t know whether this was an anomaly resulting from running

under VM, or the way it’s supposed to work.

18.5.3 The mon tool and test

For this test we used an open source monitoring tool called mon. It’s a good

general tool that can be used to monitor availability of services. These services

can be anything that can be tested with software, and they can be local or

networked services.

Note that mon itself doesn’t do the testing, but instead use ...