[CentOS] Collecting data
John R Pierce
pierce at hogranch.com
Sat Dec 25 00:14:40 UTC 2010
On 12/24/10 2:45 PM, derleader __ wrote:
>
> >> > Hi,
> >> > I'm developing C plugin for Centos which will be installed as
> >> > kernel module. The problem is how to collect the data about:
>
>
> > none of that stuff should be in a kernel module. a simple daemon is far
> > more appropriate.
>
> What is the most appropriate way to do this task?
see my prior response. A daemon is simply a usermode process thats
started when the system boots and runs as a dedicated service. In
CentOS, these are normally started via init.d scripts and the Sys V init
subsystem.
but as others have pointed out there are numerous implementations of
this already. Also, in addition to the programmatic data sources I
mentioned, much of the more realtime sort of data (cpu load, network
traffic, etc) is available via SNMP which can be queried over a network
from a data collection server, once its configured.
I wouldn't query the more 'inventory' sorts of data more than once a
day, the number of CPUs and the hardware doesn't change very often,
recording this every 5 minutes would be excessive.
> What are the benefits of the kernel module and daemon?
I know of no benefits of using a kernel module to perform what is
readily doable in usermode. kernel modules should be reserved for
things like device drivers, low level network components, file systems,
and so forth. If a kernel module faults, it brings down the whole
system catastrophically. a usermode daemon process would just
terminate, and everything else would continue running. A daemon can
run as whatever security context is appropriate for it to do its job.
Most of what you described doesn't even need root privileges, but some
may (lshw I believe won't be able to collect as much info if its not run
as root)
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