General questions related to patching and servers

Linux and Unix-Like Red Hat
1

Hi,

Can you answer the following ?

  1. How to identify server is physical or virtual server ?
  2. Why often patching is done in servers ?What is the purpose of doing OS patching in servers. ?

Regards,
Maddy

2

Command below will give us all the hardware related information including the Manufacturer and Product Names,
based on this we can identify if a server is virtual or physical.

dmidecode

Server Patching will be done for various reasons usually patches will be released by vendor to fix the security flaws.

3

I don't see how generally knowing if the server is physical or virtual makes a difference on the patching of the OS. You might need to know the firmware level for a physical server or the virtual host version I suppose, but that's probably quite specialised research.

Patches for RHEL are generally banded into three areas:-

  • Security fixes - critical updates
  • Bug fixes - corrections for errors that might be causing you a problem
  • Enhancements - updates to process or code to either make it run more efficiently or providing more function/output/options.

You should be very active patching at least the Security fixes. You may choose (or not) to apply the others, but usually a yum update will pick up everything applicable for your server. If you do this, make sure you are able to boot again afterwards and that there is space available in /boot in case it triggers a kernel rebuild in the boot.

I hope that this helps,
Robin

4

Thanks Robo and Robin..It was well explained.

5

Humm, I do not believe that this is correct information.

I have never had an RHEL update trigger a kernel rebuild anywhere yet alone in /boot. To use RHEL, you are not required to have the kernel sources or headers or even a compiler.

What actually happens is the yum update will download updated kernel and initrd binaries into /boot and modify your GRUB configuration to default boot using the new kernel/initrd. Only a configurable number of "old" kernel/initrd binaries are retained in /boot. I believe the default number is 3 but I am not in front of a RHEL system as I write this.

6

Hi Murphy,

Thanks for your detailed answer.Actually i am not an sys admin to know in-depth of what would happen during OS patching in linux box.

Anyway thanks for your answer and coming forward to explain in detail.

Regards,
Maddy