RHCSA Exam EX200 Cheat Sheet Part 3


System Recovery

1. rescue a system
2. boot with installation disc
3. rescue installed system
4. shell start shell
5.

chroot /mnt/sysimage

Virtualization

To install KVM

yum groupinstall Virtualization
chkconfig libvirtd on
service libvirtd start

Guest XML File (config details of VM)

/etc/libvirt/qemu/vm-name.xml

Guest HardDrive

/var/lib/libvirt/images

Virtual Shell

virsh
nodeinfo	 show node details
list --all	 list all the running guests
start vm-name	 start a guest
shutdown vm-name	shutdown a guest
destroy vm-name	 force shutdown
dominfo vm-name	 show guest config info
autostart vm-name	auto start a guest when the host booted up
autostart vm --disable	turn off autostart
help	 list of the commands

Virtual GUI
Virtual Machine Manager

SELinux

yum install policycoreutils setroubleshoot

To check SELinux mode

getenforce

To change SELinux mode
setenforce Permissive or setenforce 0/1 while 0 is Permissive, 1 is enforcing

/etc/selinux/config
man page
apropos selinux

To list a directory’s security context

ls -Zd /etc

To list a file’s security context

ls -Z /etc/services

To view security context of a running process

ps auZ

To change security context (copy from other file)

chcon --reference source target

To change security context

chcon -t etc_t file

To restore security context
semanage fcontext -a -t etc_t "target"
restorecon -R -v target

To read AVC alert

sealert -a /var/log/audit/audit.log

Shutdown/Restart

Shutdown

shutdown -h now (shutdown immediately)
shutdown -h +

Reboot

reboot
shutdown -r +
shutdiwn -r now
init 6
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About the Author

Alfred Tong
Author and owner of this blog. A Networking enthusiast, full time networking and systems Engineer. Generally curious about all things IT.Certifications: GIAC GSEC, CCNP-S, CCNP, CCSP, CCDP, CCNA, RHCE, JNCIA - FWV