CF911: "Enable Monitoring Server" option (new in ColdFusion 9.01) DOES NOT monitor "out of process"

Note: This blog post is from 2012. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.

BTW, today is "more about the CF Server Monitor" day today here at carehart.org. :-) In my last two entries today, I talked about related matters, regarding the impact of the 3 "start" buttons (monitoring, profiling, and memory tracking), as a followup to an older entry I did on them when the monitor came out with CF 8 in 2007. See the "related blog entries" below for more.

In the last entry, I mentioned that in 9.0.1, Adobe added a new "Monitoring Settings" page to the CF Admin, and one of the features is that ability I discussed to turn off the 3 start buttons from within the Admin.

Below that is this other feature, labeled "Enable Monitoring Server". Let me say first that has really have nothing to do with all the discussion of the "start" buttons in the previous entries.

So what does "Enabling Monitor Server" do?

All it really does (if enabled) is start a new web server (within CF) that the Server Monitor client will then use to talk to CF. That's it.

All the CF Server Monitoring activity (gathering the stats, etc.) is still done WITHIN CF itself, as it always has been (as controlled by those 3 "start" buttons discussed above). As I've explained before, the CF Server Monitor is just an interface to view that information--regardless of the web server port.

Indeed, it bears noting that if you use the "built-in web server" (offered during installation or enabled manually), so that you access the CF Admin on, for instance port 8500, then you are already accessing the CF admin from a different web server than your production traffic, assuming that's coming in via port 80 (such as from IIS or Apache).

But some people may well not enable that built-in web server, and they may access the CF Admin via the same external web server as all the other traffic. Well, if something has made CF not able to respond to all your other traffic, you may find that the CF Server Monitor also cannot respond.

So this is a 3rd, special, web server option for CF

Enter this new (yes, third) alternative web server: if enabled, then the CF Server Monitor will talk to it (on port 5500 by default).

And whereas enabling the traditional "built-in web server" involves editing XML files and restarting CF, this new CF 9.0.1 option is just a single click and it takes effect immediately. No restart required.

If you click the "server monitor" button from within the "Server Monitor" page in the CF Admin after enabling this, you'll see that it opens the monitor to that port 5500 (or whatever you tell it to use.)

FWIW, this new web server does indeed start up *within the CF memory space*, but it's very lightweight. Still, this further diminishes the mistaken assertion that somehow this feature makes the "monitor run out of process".

All that said, it's certainly a good idea to use it, of course. I just wanted to clarify what it really is, and is not, since I so often hear people still assert otherwise. I don't blame them. There's not much documentation on it, and some Adobe folks did in fact at early CF 9.0.1 launch presentations suggest this mistaken assertion. I had been a little reluctant to call it out, hoping it may have gone away, but since I still hear it, I felt compelled to go ahead and write.

Reminder of what the CF Server Monitor is, and that it is always "in process"

Again, as I've talked about previously, the CF Server Monitor is an interface to data collected within the CF instance itself. It doesn't matter what web server you use to launch the monitor. It's still going to talk (via Flash Remoting) to the CF instance to get the data that it shows you.

And yes, if CF goes down, the CF Server Monitor goes down with it. It is always an "in process" monitor (as are also FusionReactor and SeeFusion in their basic configurations.)

What if you do want to watch CF from "outside the process"?

If you want something that watches the CF instance "from the outside", that's indeed reasonable. You may want something that helps you see when one or more CF instances (perhaps on multiple machines) is acting up (or going down). That's available as another tool, separate from the CF Server monitor, called the Multiserver Monitor. IT's also a feature available in FusionReactor and SeeFusion. Indeed, it's a topic worthy of its own entry. Coming next.

Hope this was helpful to someone. I always look forward to feedback.

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