正解：

See the solution below in Explanation.
Explanation:
Solution:
dnf install -y dnf-automatic
systemctl enable --now dnf-automatic.timer
systemctl list-timers --all | grep dnf
Detailed Explanation:
* dnf-automatic provides automated update checking and installation features.
* The timer unit schedules the checks.
* RHEL 10 DNF documentation specifically documents the dnf-automatic timer units. ( Red Hat Documentation )

正解：

See the solution below in Explanation.
Explanation:
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.

正解：

See the solution below in Explanation.
Explanation:
Solution:
dnf install -y httpd policycoreutils-python-utils
mkdir -p /webdata
echo "RHEL10 Web Server" > /webdata/index.html
sed -i 's/^Listen 80/Listen 8080/' /etc/httpd/conf/httpd.conf
semanage port -a -t http_port_t -p tcp 8080
firewall-cmd --permanent --add-port=8080/tcp
firewall-cmd --reload
systemctl enable --now httpd
systemctl restart httpd
ss -tulpn | grep 8080
Detailed Explanation:
* Apache defaults to port 80, so Listen 8080 changes the service port.
* SELinux must allow Apache to bind to 8080, which is done with semanage port.
* firewall-cmd opens the port externally.
* RHEL 10 documents firewalld as the standard firewall management interface and SELinux port
labeling for confined services. ( Red Hat Documentation )

正解：

See the solution below in Explanation.
Explanation:
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 )