This chapter is from the book
This chapter is from the book
This chapter is from the book
kcweb
kcweb is one of many Web-based system-administration tools. It can be invoked from SAM or directly in a browser window. In this section you perform a variety of functions through the Web-based interface. In this section we'll perform the following in kcweb:
- View kernel parameters
- Get details on a specific kernel parameter in the bottom of the kcweb page and the man page
- Modify a dynamic kernel parameter and apply the new value
- Set an alarm to inform you when a kernel parameter exceeds the specified value
At the time of this writing, kcweb is invoked from a browser with the URL https://ip_address:1188/casey/login.cgi, where ip_address is the IP address of the system on which you want to run kcweb. Figure 5-2 shows the main screen you see after invoking kcweb.
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Figure 5-2 kcweb Showing tunables
The upper left of Figure 5-2 shows that kcweb has tunables, alarms, modules, and other functions.
Notice that in the bottom left of the figure, there is a legend that includes descriptions of the symbols used in kcweb. Those tunables with a heart next to them are dynamically tunable parameters. If you select the heart on the bar across the top of the tunables, only dynamically tunable parameters will be shown. The "not equal to" sign indicates parameters that are not set to their default value. Several other entries exist in the legend as well. This makes for viewing groups of icons easy and the legend helps identify the status of icons.
The bottom of the screen provides information about the kernel parameter selected: in this case, nproc. A graph in the bottom right shows the usage of this parameter over time. For system-wide parameters, the graph shows usage on a system basis. For user-specific or process-specific parameters, the graph includes the top five consumers of the parameter.
The constraints at the very bottom of the page give an excellent overview of the tunable. If you need to get detailed information about a kernel parameter, select the man page... button, as shown in Figure 5-3.
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Figure 5-3 kcweb Man Page of nproc
You can also modify one of the parameters by highlighting the parameter and then selecting modify <parameter name> as is done for the nproc parameter, as shown in Figure 5-4.
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Figure 5-4 kcweb Showing modify nproc
You can change the value of nproc and then select whether you want a change immediately or at the next boot.
You can set an alarm to be informed when the parameter reaches a specified threshold. Figure 5-5 shows the process of setting up this alarm.
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Figure 5-5 kcweb Showing nproc Alarm
We get to the kcweb:alarms page by selecting create new alarm... in Figure 5-5. All the parameters related to the alarm are shown in Figure 5-5. The setup of the alarm allows you to specify a threshold. All of the options for notification are shown such as sending an email
You can also work with kernel modules in the same way that you work with kernel tunables. Those that are dynamic can be loaded on-the-fly, and those that are not dynamic can be built into the kernel with a rebuild.
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Figure 5-6 kcweb Showing modules
As with tunables, modules can be dynamic. In Figure 5-6, the idds module that we worked with earlier in the chapter is shown, which is static, as well as hsx, which has a heart next to it to indicate that it is a Dynamically Loadable Kernel Module (DLKM.)
You can also view /var/adm/kc.log with change log viewer, as shown in Figure 5-7.
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Figure 5-7 kcweb Showing Log File
There is also a table of contents and index that you can refer to if you need help with any kernel-related task.
Using kcweb, you can accomplish the tasks as you can at the command line. It's a matter of preference whether you take the graphical kcweb interface or the command line approach covered earlier in the chapter.
This chapter gave a quick overview of kcweb, which included some of the most commonly performed tasks. Because this is a Web-based interface, it is easy to use and most of the screens and information are self-explanatory. Other Web-based management tools can be invoked through SAM including pdweb and parmgr; those are covered in other chapters.