Exam Preps

Question 1

Install the Apache package. Allow it to get documents stored on NFS mounted directories.

Answer 1

# yum install -y httpd
# firewall-cmd –permanent –add-service=http
# firewall-cmd –reload
# systemctl enable httpd
# systemctl start httpd
# getsebool -a | grep nfs | grep httpd
# setsebool -P httpd_use_nfs on

Question 2

Extend the existing xfs file system to a total size of 200MB and add a label called myFS.

Answer 2

# lvextend –size 200M -r /dev/vg/lv_xfs
or # lvextend –size +100M -r /dev/vg/lv_xfs
# umount /xfs
# xfs_admin -L “myFS” /dev/vg/lv_xfs
# mount /xfs

Question 3

Create two users: john with uid/gid equal to 2000, password 12345678 and davis with uid/gid equal to 3000, password 87654321. Make davis‘ account validity stopping in one month.

Answer 3

# useradd -u 2000 john
# passwd john
New password: 12345678
# useradd -u 3000 davis
# passwd davis
New password: 87654321
# date -d “+1month”
# usermod -e YYYY-MM-DD davis
or # chage -E YYYY-MM-DD davis
# chage -l davis

Question 4

Allow davis (and only davis) to get full access to john‘s home directory.

Answer 4

setfacl -R -m u:davis:rwx /home/john

Question 5

Create a directory named /common. Allow john and davis to share documents in the /common directory using a group called team. Both of them can read, write and remove documents from the other in this directory but any user not member of the group can’t.

Answer 5

# mkdir /common
# groupadd -g 50000 team
# chgrp team /common
# chmod 2770 /common
# usermod -aG team john
# usermod -aG team davis

Question 6

Create a xfs file system on a new logical volume of 100MB called lv_xfs. Mount it permanently with uuid under /xfs.

Answer 6

# lvcreate –size 100M –name lv_xfs /dev/vg
# mkfs.xfs /dev/vg/lv_xfs
# mkdir /xfs
# blkid | grep lv_xfs >> /etc/fstab
# vi /etc/fstab
UUID=… /xfs xfs defaults 1 2
# mount -a

Question 7

Write a Bash script called prog.sh in the /root directory that creates 40 files of 2MB each with the fallocate command in the mounted /xfs directory. Each file has got a name as follows: .file_N where N is a number from 1 to 40.

Answer 7

cd /root
vi prog.sh
#!/bin/bash

cd /xfs
N=40
while [ “$N” -gt 0 ]
do
fallocate -l 2M .file_$N
N=`expr $N – 1`
done
——————–
# chmod u+x prog.sh
# ./prog.sh

Question 8

Create an ext4 file system on a new logical volume of 100MB called lv_ext4. Mount it permanently under the /ext4 directory. Copy the files previously created into this new space.

Answer 8

# lvcreate –size 100M –name lv_ext4 /dev/vg
# mkfs.ext4 /dev/vg/lv_ext4
# mkdir /ext4
# vi /etc/fstab
/dev/vg/lv_ext4 /ext4 ext4 defaults 1 2
# cp -p /xfs/.f* /ext4

Question 9

Assign the same SELinux contexts used by the home directories to the /xfs directory permanently.

Answer 9

# yum install -y setroubleshoot-server
# semanage fcontext -a -t user_home_t “/xfs(/.*)?”
# restorecon -R /xfs

Question 10

Configure a virtual console.

Answer 10

grubby –update-kernel=ALL –args=”console=ttyS0″

Question 11

Create a logical volume of 200MB called lv_swap2 and add it permanently to the current swap space.

Answer 11

# lvcreate –size 200M –name lv_swap2 /dev/vg
# mkswap /dev/vg/lv_swap2
# swapon /dev/vg/lv_swap2
vi /etc/fstab
/dev/vg/lv_swap2 swap swap defaults 0 0

Question 12

Create a cron job running as root, starting at 11PM every day and writing a report on daily system resource consumption in the /var/log/consumption.log file.

Answer 12

# crontab -e
00 23 * * * /usr/bin/sar -A > /var/log/consumption.log

Question 13

Set the default target to boot into X Window level (previously level 5).

Answer 13

systemctl set-default graphical.target

Question 14

Change the hostname to mycentos.example.com

Answer 14

hostnamectl set-hostname mycentos.example.com