17.) Review

Question 1

What do you do if a computer won’t boot to login

Answer 1

Edit grub with "e". 
Add systemd.unit=emergency.target.
press ctrl+x
# mount -o remount,rw /
# vim /etc/fstab
# systemctl daemon-reload
# systemctl reboot

Question 2

switch to multi-user target

Answer 2

# systemctl get-default
# systemctl isolate multi-user.target

Question 3

Schedule a recurring job on an hourly bassis between 7-9pm on all days except Saturday and Sunday

Answer 3

$ crontab -e
0 19-21 * * Mon-Fri /home/me/run.sh
$ crontab -l

Question 4

Create a 2GB partition on /dev/vdb

Answer 4

# parted /dev/vdb mklabel msdos
# parted /dev/vdb mkpart primary 1GiB 3GiB
# parted /dev/vdb set 1 lvm on

Question 5

Create a logical volume called vol_home using a 2GiB partition

Answer 5

# pvcreate /dev/vdb1
# vgcreate extra_storage /dev/vdb1
# lvcreate -L 1GiB -n vol_home extra_storage
# mkdir /home
mkfs -t xfs /dev/extra_storage/vol_home

Question 6

persistant mount newly created storage

Answer 6

# echo "UUID=88 /home xfs defaults 0 0" /etc/fstab
# mount -a

Question 7

mount network share persistently

Answer 7

echo “10.x.x.87:/share /work nfs rw,sync 0 0”&raquo_space; /etc/fstab

Question 8

create 512MiB swap

Answer 8

# parted /dev/vdc mklabel msdos
# parted /dev/vdc primary linux-swap 1MiB 513MiB
# mkswap /dev/vdc1
# echo "UUID=888 swap swap defaults 0 0 " >>ftsab
# swapon -a

Question 9

create users Rabbit1,2,3,4and add them to a group Haus

Answer 9

# groupadd Haus
# for i in 1 2 3 4; do useradd -G Haus Rabbit$i; done

Question 10

configure /run/volatile to store files. Cleanup every 30 seconds. Permissions 0700

Answer 10

# echo "d /run/volatile 0700 root root 30s" >> /etc/tmpfiles.d/volatile.conf
# systemd-tmpfiles --create /etc/tmpfiles.d/volatile.conf

Question 11

Configure /home directories to automatically mount

Answer 11

# yum install autofs
# echo "/- /etc/auto.moocow" >> /etc/auto.master.d/moo.autofs
# echo "/home/rabbit -rw x.x.x.x:/homedirs/rabbit
# systemctl restart autofs

Question 12

Retrieve a user’s home direcctory path

Answer 12

getent passwd rabbit

Question 13

Configure SELinux to enable nfs home directories

Answer 13

setsebool -P use_nfs_homedirs true

Question 14

Adjust firewall settings so that SSH connectings are rejected from x.x.x.x

Answer 14

# firewall-cmd --add-source=x.x.x.x/32 --zone=block --permanent
# firewall-cmd --reload

Question 15

Troubleshoot httpd.service being blocked on port 8080

Answer 15

# systemctl status httpd
# sealert -a /var/log/audit/audit.log
# semanage port -a -t http_port_t -p tcp 30080
# systemctl restart httpd
# firewall-cmd --add-port=30080/tcp --permanent
# firewall-cmd --reload