Pass the RedHat RHCSA EX200 Questions and answers with CertsForce

Solution:

firewall-cmd --permanent --add-service=http

firewall-cmd --reload

firewall-cmd --list-services

Detailed Explanation:

--permanent saves the rule.

--reload applies it.

--list-services verifies the active configuration.

Firewalld remains the standard firewall interface in RHEL 10. ( Red Hat Documentation )

Solution:

Open the firewall port and HTTP service:

firewall-cmd --permanent --add-port=82/tcp

firewall-cmd --permanent --add-service=http

firewall-cmd --reload

Add SELinux port labeling:

semanage port -a -t http_port_t -p tcp 82

Detailed Explanation:

firewall-cmd --permanent makes the change persistent.

--add-port=82/tcp opens the custom TCP port.

--add-service=http keeps standard HTTP allowed too.

SELinux blocks services on unexpected ports unless the port is labeled correctly.

http_port_t tells SELinux that port 82 is valid for web services.

Solution:

Partition the disk:

fdisk /dev/sdb

Inside fdisk:

n = new partition

p = primary

1 = partition number

accept defaults

size +700M

t = change type

set Linux LVM type

w = write changes

Create the physical volume:

pvcreate /dev/sdb1

Create the volume group:

vgcreate vg_data /dev/sdb1

Create the logical volume:

lvcreate -L 500M -n lv_data vg_data

Create the filesystem:

mkfs.xfs /dev/vg_data/lv_data

Detailed Explanation:

The lab specifies a 700 MB partition and a 500 MB logical volume.

pvcreate initializes the partition for LVM.

vgcreate builds the storage pool.

lvcreate allocates space from the volume group.

mkfs.xfs creates the filesystem, which is standard on RHEL.

Solution:

Create timer unit:

cat > /etc/systemd/system/backup-now.timer < < 'EOF'

[Unit]

Description=Daily backup timer

[Timer]

OnCalendar=*-*-* 02:00:00

Persistent=true

[Install]

WantedBy=timers.target

EOF

Enable it:

systemctl daemon-reload

systemctl enable --now backup-now.timer

systemctl list-timers --all | grep backup-now

Detailed Explanation:

OnCalendar=*-*-* 02:00:00 means daily at 02:00.

Persistent=true runs missed jobs after boot if the system was off.

timers.target is the normal target for timer units.

RHEL 10 documentation includes systemd timer units as a standard scheduling mechanism. ( Red Hat Documentation )

Solution:

mkdir -p /share/projects

chown alex /share/projects/

chmod a+rwx,+t /share/projects/

ls -ld /share/projects/

Detailed Explanation:

chmod a+rwx gives read, write, and execute to everyone.

+t sets the sticky bit.

Sticky bit on a shared directory means users can create files, but only the file owner, directory owner, or root can delete them.

This is the same model used on /tmp.

Solution:

Read-only access:

setfacl -m u:john:r-- /share/dev

Read-write access:

setfacl -m u:john:rw- /share/dev

Remove ACL permissions:

setfacl -m u:john:--- /share/dev

Detailed Explanation:

setfacl -m modifies the ACL.

u:john:r-- grants read only.

u:john:rw- grants read and write.

u:john:--- effectively removes access for that ACL entry.

ACLs are used when standard owner/group/other permissions are not enough.

Solution:

echo "john" > > /etc/cron.deny

Detailed Explanation:

cron.deny blocks listed users from using cron.

This is the simplest way to deny scheduled-job access for one user.

Solution:

dnf install -y vdo kmod-kvdo lvm2

pvcreate /dev/sdc

vgcreate vdo-volumegroup /dev/sdc

lvcreate --type vdo -n vdo-logicalvolume -L 5G -V 50G vdo-volumegroup/vdo-pool

mkfs.xfs /dev/vdo-volumegroup/vdo-logicalvolume

Detailed Explanation:

VDO provides compression and deduplication.

-L 5G sets the physical backing size.

-V 50G sets the logical exposed size.

This allows thin, optimized storage presentation.

The exact commands are taken from the RHCSA dataset embedded in the uploaded lab HTML.

Solution:

Create the Quadlet file:

mkdir -p /etc/containers/systemd

cat > /etc/containers/systemd/sleepy.container < < 'EOF'

[Container]

Image=registry.access.redhat.com/ubi10/ubi

ContainerName=sleepy

Exec=sleep 3600

[Install]

WantedBy=multi-user.target

EOF

Reload and enable:

systemctl daemon-reload

systemctl enable --now sleepy.service

systemctl status sleepy.service

Detailed Explanation:

Quadlet is the preferred modern way to manage Podman containers with systemd for new configurations.

The .container file is translated into a systemd-managed service.

RHEL 10 documentation notes that podman generate systemd still exists, but Quadlets are preferred for new setups. ( Red Hat Documentation )

Solution:

mkdir -p /root/d1

find /usr/local -type f -size +3k -size -5k -exec cp -rvf {} /root/d1/ \;

chmod g+s /root/d1

ls -ld /root/d1

Detailed Explanation:

-size +3k means greater than 3 KB.

-size -5k means less than 5 KB.

chmod g+s sets the SGID bit on the directory.

SGID on a directory causes new files created there to inherit the directory’s group.