Red Hat Linux Interview Series 7

[Chetan_Tiwary_]

Q.) How will you troubleshoot this issue with httpd service :

[root@rhel9 ~]# systemctl status -l httpd
● httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/httpd.service.d
           └─10-dependencies.conf
   Active: inactive (dead)


Sep 19 21:50:42 rhel9.lab.example.com systemd[1]: httpd.service: Unable to break cycle starting with httpd.service/start
Sep 19 21:50:42 rhel9.lab.example.com systemd[1]: vsftpd.service: Found ordering cycle on httpd.service/start

Q.) After rebooting a RHEL server, the host shuts down but fails to boot. What will you do to get it working back :

error: ../../grub-core/loader/i386/pc/linux.c:170:invalid magic number. 
error: ../../grub-core/loader/i386/pc/linux.c:1418:you need to load the kernel first. 
Press any key to continue…

Q.)  Accidentally removed an lvm , can it be restored back ? How ?

[root@rhel9 ~]# lvremove /dev/vg1/lvm1
Do you really want to remove active logical volume "lvm1"? [y/n]: y
  Logical volume "lvm1" successfully removed

I'll be posting a series of Linux-related questions covering various skill levels. Feel free to share your insights and expertise. Your contributions will benefit learners at all stages, from those in current roles to those preparing for Linux interviews.

[rhnoname]

Uhm, interesting questions:

1) I would check the systemd unit file for the httpd service. If remember properly the issue should be related to the "Requires" and/or "After" misconfiguration. I guess to solve this issue vsftpd needs to be specified as a requirement before starting the httpd service.

2) Try to boot another kernel if any or go into the emergency mode, reinstall the grub from scratch and then reboot the system again. It should fix it up.

3) Find the backup of the deleted volume with:

vgcfgrestore --list <my_volgrp>

The backup should have been saved under /etc/lvm/archive/

restore the backup with

vgcfgrestore -f /etc/lvm/archive/<backup name> my_volgrp

activate the volume

lvchange -a y /dev/my_volgrp/my_restored_volume 

I hope I did guess at least one out of three

I am sure there are a lot of more skilled people than me out there

RN