This post is part of a series exploring the unique aspects and capabilities of WebSphere Liberty when running on z/OS.
We'll also explore considerations when moving from WebSphere traditional on z/OS to Liberty on z/OS.
The next post in the series is here.
To start at the beginning, follow this link to the first post.
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I call this last section the “Where am I and what am I doing here?” section. We start off by printing out the “os” value. This is going to give you information about the operating system you’re running Liberty on. If you’re still reading this blog, you’re probably on z/OS (at least). And that’s what it shows, but also some more interesting stuff.
The ‘os’ value is actually in 3 parts. The first part is the operating system name itself, which here is, of course, “z/OS” (with a proper lower case ‘z’). The second part, in parenthesis, is the level of the operating system and the architecture. In my case that was “02.05.00” and “s390x”. That means I’m running on z/OS 2.5 which is, obviously, an s390x architecture.
That information, still in the ‘os’ is followed, also in parenthesis, by the locale. For me that’s “en_US” for US English.
All these references to things “in parenthesis” is causing me “Alice’s Restaurant” flashbacks…. If you’re old enough to remember that…if not, look it up…still a great song.
Anyway…after the ‘os’ value we’ve got the ‘process’ value. No parenthesis here, but instead two values separated by an ‘@’ sign. Before the ‘@’ we’ve got the process id for the Unix process running the server (since we’re on z/OS that’s a USS process id). You should be able to get information about it using ‘ps’ commands from the shell or with the D OMVS command from the console.
On the other side of the ‘@’ is the host name where the server is running. This is just the hostname without a domain qualification. Basically this line is saying I’m in this process on this host.
All of that…the operating system information, the locale, process id and host name, answers the “Where am I?” part of the question.
For the “What am I doing here?” part we go to the last two entries in the message log header which are classpath and library path (libpath). Classpath tells the JVM where Java classes, loaded with the system class loader, can be found. It is probably not very long. In the logs I’ve looked at it mostly seems to point to the .jar used to launch the server.
The libpath on the other hand can be quite long. This lists all the paths where load modules that get loaded by the server might be. Depending on what you’re doing, this could be quite a list. Having the right stuff in here is going to be very important.
So if you find yourself asking, “Who am I? Where am I? What am I doing here?” you can just have a look at the message log header! Or perhaps seek professional help.