Chapter 10. Web services scenario 353
2. Under Additional Properties click Destinations.
3. In the list of destinations, check the box to the left the queue name. In this
case, the queue is DeliveryResponseDestination.
Click the Mediate button.
4. In the next screen, select DeliveryResponseMediation as the mediation to
apply to the destination.
Click Next.
5. In the next screen, select the bus and click Next.
6. Click Finish.
Save your changes.
10.8 System management for Web services
Planning for systems management in a Web services environment is similar to
the planning needed for any other distributed system, but we face some unique
challenges in Web services technology.
Web services are based on plain text XML messaging that could potentially be
vulnerable to interception. In addition, Web services potentially allow
transactions beyond firewalls and enable external entities to invoke internal
applications or access sensitive information.
Another problem is that since there is no confirmed delivery (at least not explicitly
built into the Web services specification) what happens if we do not get a
response to a particular request? How do we know if the Web service provider is
not working, just slow, or just did not receive our request?
We have no explicit way of determining if a service on a remote server (not under
our control) is working. This becomes an availability issue on our local server. At
the application level, we need a way to respond to unavailable systems.
Some other areas of system management to consider with Web services include:
Firewall considerations
From the perspective of the firewall, an RPC router is just another servlet that
is accessed through HTTP or HTTPS.
Load-balancing considerations
– The same considerations and techniques as for normal servlets apply,
with one exception. By default, there is no hot failover for session type
Web services. If failover is a requirement, it should be handled on the next
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