EX200 Red Hat Certified System Administrator - RHCSA (8.2) Questions and Answers

• Create a partition having size 5 GB and change the syste id '8e'.
• use partprobe command
• pvcreate /dev/hda9 Suppose your partition number is hda9.
• vgextend test0 /dev/hda9 vgextend command add the physical disk on volume group.
• lvextend -L+5120M /dev/test0/lvtestvolume
• verify using lvdisplay /dev/test0/lvtestvolume.

The LVM system organizes hard disks into Logical Volume (LV) groups. Essentially, physical hard disk partitions (or possibly RAID arrays) are set up in a bunch of equal sized chunks known as Physical Extents (PE). As there are several other concepts associated with the LVM system, let's start with some basic definitions:

Physical Volume (PV) is the standard partition that you add to the LVM mix. Normally, a physical volume is a standard primary or logical partition. It can also be a RAID array.

Physical Extent (PE) is a chunk of disk space. Every PV is divided into a number of equal sized PEs. Every PE in a LV group is the same size. Different LV groups can have different sized PEs.

Logical Extent (LE) is also a chunk of disk space. Every LE is mapped to a specific PE.

Logical Volume (LV) is composed of a group of LEs. You can mount a file system such as /home and /var on an LV.

Volume Group (VG) is composed of a group of LVs. It is the organizational group for LVM. Most of the commands that you'll use apply to a specific VG.

• Verify the size of Logical Volume: lvdisplay /dev/vg0/lv1
• Verify the Size on mounted directory: df -h or df -h mounted directory name
• Use: lvextend -L+400M /dev/vg0/lv1
• ext2online -d /dev/vg0/lv1 to bring extended size online.
• Again Verify using lvdisplay and df -h command.

*

[root@node2 ~]# lsblk

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT

vdd 252:48 0 5G 0 disk

vde 252:64 0 10G 0 disk

[root@node2 ~]# yum install kmod-kvdo vdo

[root@node2 ~]# systemctl enable --now vdo

[root@node2 ~]# systemctl start vdo

[root@node2 ~]# systemctl status vdo

[root@node2 ~]# vdo create --name=vdo1 --device=/dev/vde --vdoLogicalSize=50G

[root@node2 ~]# vdostats --hu

Device Size Used Available Use% Space saving%

/dev/mapper/vdo1 10.0G 4.0G 6.0G 40% N/A

[root@node2 ~]# mkfs.xfs -K /dev/mapper/vdo1

*

[root@node2 ~]# lsblk

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT

vde 252:64 0 10G 0 disk

└─vdo1 253:4 0 50G 0 vdo

[root@node2 ~]# mkdir /vbread

[root@node2 ~]# blkid

/dev/mapper/vdo1: UUID="1ec7a341-6051-4aed-8a2c-4d2d61833227" BLOCK_SIZE="4096" TYPE="xfs"

[root@node2 ~]# vim /etc/fstab

UUID=1ec7a341-6051-4aed-8a2c-4d2d61833227 /vbread xfs defaults,x-systemd.requires=vdo.service 0 0

[root@node2 ~]# mount /dev/mapper/vdo1 /vbread/

[root@node2 ~]# df -hT

Filesystem Type Size Used Avail Use% Mounted on

/dev/mapper/vdo1 xfs 50G 390M 50G 1% /vbread

[root@node1 ~]# find / -name natasha -type f > /home/natasha/files

[root@node1 ~]# cat /home/natasha/files

/var/spool/mail/natasha

/mnt/shares/natasha

[root@node1 ~]# mkdir /find

[root@node1 ~]# find /etc -size +5M > /find/largefiles

[root@node1 ~]# cat /find/largefiles

/etc/selinux/targeted/policy/policy.31

/etc/udev/hwdb.bin

fdisk -cu /dev/vda// Create a 1G partition, modified when needed

partx –a /dev/vda

pvcreate /dev/vdax

vgcreate datastore /dev/vdax –s 16M

lvcreate– l 50 –n database datastore

mkfs.ext3 /dev/datastore/database

mkdir /mnt/database

mount /dev/datastore/database /mnt/database/ df –Th

vi /etc/fstab

/dev/datastore /database /mnt/database/ ext3 defaults 0 0 mount –a

Restart and check all the questions requirements.

*

•

[root@host ~]#systemctl enable sssd.service

[root@host ~]#systemctl start sssg.service

[root@host ~]#getent passwd remoteuser15

[root@host ~]#yum install autofs

[root@host ~]#vim /etc/auto.master.d/home9.autofs

/netdir/remoteuser15 /etc/auto.home9

[root@host ~]#vim /etc/auto.home9

remoteuser15 –rw,sync utility.network15.example.com:/netdir/remoteuser15/&

[root@host ~]#systemctl enable autofs

[root@host ~]#systemctl restart autofs

[root@host ~]#su - remoteuser15

# cd /etc/syscofig/network-scripts/

# ls

# vim ifcfg-eth0 (Configure IP Address, Gateway and DNS) IPADDR=172.24.40.40

GATEWAY=172.24.40.1

DNS1=172.24.40.1

# vim /etc/sysconfig/network

(Configure Host Name)

HOSTNAME= station.domain40.example.com

OR

Graphical Interfaces:

System->Preference->Network Connections (Configure IP Address, Gateway and DNS) Vim /etc/sysconfig/network

(Configure Host Name)

*

[root@node1 ~]# tar cvf /root/backup.tar /usr/local/

tar: Removing leading `/' from member names

/usr/local/

/usr/local/bin/

/usr/local/etc/

[root@node1 ~]# ls

backup.tar

[root@node1 ~]# file backup.tar

backup.tar: POSIX tar archive (GNU)

[root@node1 ~]# bzip2 backup.tar

[root@node1 ~]# ls

backup.tar.bz2

[root@node1 ~]# file backup.tar.bz2

backup.tar.bz2: bzip2 compressed data, block size = 900k

•

[root@node1 ~]# sestatus

SELinux status: enabled

[root@node1 ~]# cat /etc/selinux/config

SELINUX=enforcing

SELINUXTYPE=targeted

[root@node1 ~]# reboot

### For Checking ###

[root@node1 ~]# sestatus

SELinux status: enabled

*

[root@node1 ~]# cp -p /etc/fstab /var/tmp/

[root@node1 ~]# ls -lrt /etc/fstab

[root@node1 ~]# ls -lrt /var/tmp/fstab

[root@node1 ~]# chmod a+x /var/tmp/fstab

[root@node1 ~]# getfacl /var/tmp/fstab

[root@node1 ~]# setfacl -m u:harry:rw- /var/tmp/fstab

[root@node1 ~]# setfacl -m u:natasha:--- /var/tmp/fstab

[root@node1 ~]# getfacl /var/tmp/fstab

getfacl: Removing leading '/' from absolute path names

# file: var/tmp/fstab

# owner: root

# group: root

user::rwx

user:harry:rw-

user:natasha:---

group::r-x

mask::rwx

other::r-x

*

[root@node1 ~]# su - natasha

[natasha@node1 ~]$ cat /var/tmp/fstab

cat: /var/tmp/fstab: Permission denied

* [root@node1 ~]# vim /etc/yum.repos.d/redhat.repo

[BaseOS]

name=BaseOS

baseurl=https://utility.domain15.example.com/BaseOS

enabled=1

gpgcheck=1

gpgkey=https://utility.domain15.example.com/RPM-GPG-KEY-redhat-release

[AppStream]

name=AppStream

baseurl=https://utility.domain15.example.com/AppStream

enabled=1

gpgcheck=1

gpgkey=https://utility.domain15.example.com/RPM-GPG-KEY-redhat-release

[root@node1 ~]# yum clean all

[root@node1 ~]# yum repolist

[root@node1 ~]# yum list all

useradd -u 3400 iar

passwd iar

# cd /root; wget ftp://192.168.0.254/pub/boot.iso

# mkdir -p /media/cdrom

# vim /etc/fstab

/root/boot.iso /media/cdrom iso9660 defaults,loop 0 0

# mount -a

mount [-t vfstype] [-o options] device dir

/proc is the virtual filesystem, containing the information about the running kernel.

To change the parameter of running kernel you should modify on /proc. From Next reboot the system, kernel will take the value from /etc/sysctl.conf.

• /etc/yum.repos.d/base.repo

[base]

name=base

baseurl=https://instructor.example.com/pub/rhel6/dvd

gpgcheck=0

yum list

fdisk /dev/vda

pvcreate /dev/vda3

vgcreate –s 16M vg0 /dev/vda3

lvcreate –n lv0 –l 20 vg0

mkfs.ext3 /dev/mapper/vg0-lv0

mkdir /data

/etc/fstab:

/dev/mapper/vg0-lv0 /data ext3 defaults 0 0

mount –a

mount | grep data

*

[root@workstation ~]# ssh shangrila@node1

[shangrila@node1 ~]$ podman login registry.domain15.example.com:5000

Username: admin

Password:

Login Succeeded!

[shangrila@node1 ~]$ podman pull registry.domain15.example.com:5000/rhel8/rsyslog

[shangrila@node1 ~]$ podman run -d --name logserver registry.domain15.example.com:5000/rhel8/rsyslog

021b26669f39cc42b8e94eab886ba8293d6247bf68e4b0d76db2874aef284d6d

[shangrila@node1 ~]$ mkdir -p ~/.config/systemd/user

[shangrila@node1 ~]$ cd ~/.config/systemd/user

*

[shangrila@node1 user]$ podman generate systemd --name logserver --files --new

/home/shangrila/.config/systemd/user/container-logserver.service

[shangrila@node1 ~]$ systemctl --user daemon-reload

[shangrila@node1 user]$ systemctl --user enable --now container-logserver.service

[shangrila@node1 ~]$ podman ps

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

7d9f7a8a4d63 registry.domain15.example.com:5000/rhel8/rsyslog:latest /bin/rsyslog.sh 2 seconds ago logserver

[shangrila@node1 ~]$ sudo reboot

[shangrila@node1 ~]$ cd .config/systemd/user

[shangrila@node1 user]$ systemctl --user status

# useradd -G admin harry

# useradd -G admin natasha

# useradd -s /sbin/nologin tom

# id harry;id Natasha (Show additional group)

# cat /etc/passwd

(Show the login shell)

OR

# system-config-users