RHCSA

Question 1

How to enable port forwarding

Answer 1

vi /etc/sysctl.conf
	# add line
	net.ipv4.ip_forward=1
	# save file
	sysctl -p

Question 2

Disk compression

Answer 2

VDO

Question 3

Layered storage

Answer 3

Stratis

Question 4

First thing in any script

Answer 4

!/bin/bash

Question 5

Shell script user prompt for input

Answer 5

read VARIABLENAME

Question 6

default exit codes for successful and unsuccessful

Answer 6

exit 0 = unsuccessful exit 1 = successful

Question 7

Numerical calculations within a bash script

Answer 7

$((1+2))

Question 8

How to call a variable in a bash script

Answer 8

$VARIABLE

Question 9

How to create a local repo

Answer 9

create mount point (mkdir /repo)
add to /etc/fstab: /rhel8.iso /repo iso9660 defaults 0 0
mount -a

/etc/yum.repos.d
	[appstream]
	name=appstream
	enabled=1
	baseurl=file:///repo/AppStream
	gpgcheck=0

Question 10

2 things to never forget when using firewall-cmd

Answer 10

always run with and without permanent

always restart firewall-cmd after any changes

Question 11

How to rename a file in linux

Answer 11

mv

Question 12

set time zone

Answer 12

timedatectl set-timezone

Question 13

How to modify boot and kernel options

Answer 13

/etc/default/grub (most commonly worked with, timeout time, etc, feeds changes to grub2-mkconfig)
/boot/grub2/grub.cfg (final product of grub2-mkconfig)
***Executing change to bootloader: grub2-mkconfig -o /boot/grub2/grub.cfg
grub2-set-default will change which kernal boots 0 is the first
GRUB_TIMEOUT_STYLE=hidden

Question 14

Packages required for Stratis

Answer 14

stratisd, stratis-cli

Question 15

Packages required for VDO

Answer 15

vdo, kmod-kvdo

Question 16

If having issues with stratis, how to wipe disk

Answer 16

wipefs -a /disk

Question 17

fstab configuration for stratis

Answer 17

UUID /mountpoint xfs x-systemd.requires=stratisd.service

ALWAYS USE UUID
lsblk -o=UUID /dev/stratis/mypool/myfs

Question 18

fstab option required for vdo

Answer 18

x-systemd.requires=vdo.service

Question 19

Where and how to set up nfs export on nfs server

Answer 19

/etc/exports

/dir 10.1.1.1(rw)

exportfs -av

Question 20

NFS packages

Answer 20

autofs, nfs-utils, nfs-server

Question 21

NFS firewall services

Answer 21

nfs, mountd, rpc-bind

Question 22

How to check available mount points for remote device

Answer 22

showmount -e 10.1.1.1

Question 23

NFS fstab setup

Answer 23

option = _netdev

file system type = nfs

Question 24

Samba share options

Answer 24

_netdev, username=user, password=password

yum install samba, yum install samba-client

Question 25

NFS SEboolean

Answer 25

setsebool -P nfs_export_all_rw on

JUST USE SETSEBOOL -P NFS TAB TAB

Question 26

podman packages

Answer 26

podman and container-tools

Question 27

User persistent container - dont forget

Answer 27

loginctl enable-linger USER (run from root)

Question 28

location to run, and command for generating systemd podman USER file

Answer 28

/.config/systemd/user
podman generate systemctl –files web_dev (–new for new every time)

systemctl –user daemon-reload

NOTE - ONLY WORKS FROM SSH OR CONSOLE, NOT SUDO OR SU

Question 29

location to run, and command for generating systemd podman USER file

Answer 29

/etc/systemd/system

podman generate systemctl –files web_dev (–new for new every time)

Question 30

Persistent mount storage on container

Answer 30

• v ~/web_data:/var/www/html:Z

- v and Z

Question 31

Execute command within container

Answer 31

podman exec mycontainer cat /etc/whatever

Question 32

Check container log

Answer 32

podman logs containername

VERY IMPORTANT IF CONTAINER FAILS TO LAUNCH

Question 33

Specify environment variables when creating container

Answer 33

-e

EX:

podman run -d –name mysql -e MYSQL_ROOT_PASSWORD=password

Question 34

How to execute a command with results of find

Answer 34

find / -type f -perm 0777 -print -exec chmod 644 {} \;

MOST IMPORTANT THINGS TO REMEMBER:
{} = passes output of find
\; ends the execute

GREAT EXAMPLES IN THE MAN PAGE

Question 35

How to extend xfs filesystem

Answer 35

xfs_growfs

Question 36

How to extend ext4 filesystem

Answer 36

resize2fs

Question 37

Settings for usermod userdel and chage

Answer 37

/etc/login.defs