EX200 Practice Test 20 — 15 Questions

Question 1

An administrator replaces a failed disk in a RAID 10 array /dev/md0. The new disk is /dev/sdc. The admin runs: mdadm /dev/md0 --add /dev/sdc. The command succeeds, but the array does not start rebuilding. What is the most likely reason?

Accepted Answer

The failed disk was not removed from the array first; you need to mark it as failed and remove it.. Option D is correct because when a disk in a RAID array fails, the array marks it as faulty but does not automatically remove it. The administrator must first explicitly mark the failed disk as failed with `mdadm --fail` and then remove it with `mdadm --remove` before adding a replacement. Without removing the failed device, the array still considers the old disk as part of the array, and the new disk is not recognized as a replacement, so no rebuild starts.

Answer

The new disk must be partitioned with the same layout as the failed disk.

Answer

The --add command should have been --re-add instead.

Answer

The array is still clean and does not need the new disk yet.

Question 2

A storage administrator is asked to increase the size of an ext4 filesystem mounted at /data. The underlying logical volume /dev/mapper/vg01-lv01 is currently 10GB and the volume group has 5GB of free extents. After extending the logical volume by 2GB using lvextend -L +2G /dev/mapper/vg01-lv01, what command must be run to resize the filesystem?

Accepted Answer

resize2fs /dev/mapper/vg01-lv01. After extending the logical volume with `lvextend`, the filesystem does not automatically recognize the new space. For ext4 filesystems, the `resize2fs` command must be run to resize the filesystem to use the additional logical volume capacity. This command can be executed online (while the filesystem is mounted) and will expand the filesystem to fill the available space in the logical volume.

Answer

lvextend -r -L +2G /dev/mapper/vg01-lv01

Answer

xfs_growfs /data

Answer

fsck -f /dev/mapper/vg01-lv01

Question 3

An administrator attempts to mount an XFS filesystem from /dev/sdc1 to /mnt/archive but receives the error: 'mount: /mnt/archive: wrong fs type, bad option, bad superblock on /dev/sdc1, missing codepage or helper program, or other error.' The output of 'dumpe2fs /dev/sdc1' shows 'dumpe2fs: Bad magic number in super-block while trying to open /dev/sdc1'. What is the most likely problem?

Accepted Answer

The filesystem on /dev/sdc1 is XFS, not ext4. The error message 'wrong fs type' combined with 'dumpe2fs: Bad magic number in super-block' indicates that the filesystem on /dev/sdc1 is not an ext2/3/4 filesystem. dumpe2fs is designed to read ext2/3/4 superblocks, and the 'bad magic number' error means it cannot find a valid ext superblock. Since the administrator is trying to mount an XFS filesystem, the correct tool to examine it is xfs_db or xfs_info, not dumpe2fs. Therefore, the most likely problem is that the filesystem is XFS, not ext4.

Answer

The mount point /mnt/archive does not exist

Answer

The XFS kernel module is not loaded

Answer

The partition /dev/sdc1 does not exist

Question 4

A container needs to share the host's network namespace for performance monitoring. Which podman run option achieves this?

Accepted Answer

--network host. Option D is correct because `--network host` makes the container use the host's network stack directly, bypassing any network namespace isolation. This allows performance monitoring tools inside the container to see the host's actual network interfaces, IP addresses, and traffic without NAT or port mapping overhead.

Answer

--network slirp4netns

Answer

--network bridge

Answer

--network none

Question 5

Which TWO of the following are valid reasons to use LVM in a Red Hat Enterprise Linux environment?

Accepted Answer

Ability to resize logical volumes without repartitioning. Option B is correct because LVM allows you to resize logical volumes (LVs) online or offline without needing to repartition the underlying disk, which is a key advantage over traditional partitions. Option C is correct because LVM provides snapshot functionality, which creates a point-in-time copy of a logical volume for consistent backups or testing, without requiring additional backup software.

Answer

Improved disk I/O performance over direct partitions

Answer

Simplification of disk partitioning by removing the need for partitions

Answer

Ability to create RAID arrays without mdadm

Question 6

A system administrator is configuring a new RHEL 9 server with two 500GB SSDs. The requirement: create a 200GB XFS filesystem for /srv/data that is resilient to disk failure. The admin decides to create a RAID 1 (mirror) using mdadm with partitions on each disk: /dev/sda1 and /dev/sdb1, each 200GB. He creates the partitions with fdisk, then runs: mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1. The array is created and synced. He then creates a physical volume, volume group, and logical volume on top of /dev/md0, formats with XFS, and mounts. Later, a disk fails. After replacing the failed disk, he recreates the partition with identical size and runs: mdadm /dev/md0 --add /dev/sdb1. The command fails with 'Device /dev/sdb1 is busy'. What is the most likely cause?

Accepted Answer

The kernel still sees the old partition table; need to run partprobe to reread the partition table.. Option B is correct because after replacing a failed disk and recreating the partition, the kernel's in-memory partition table still reflects the old state. The `mdadm --add` command fails with 'Device busy' because the kernel sees the old partition layout and may still hold references to the old partition. Running `partprobe` (or `partx -a`) forces the kernel to reread the partition table from the disk, clearing the stale state and allowing the new partition to be added to the RAID array.

Answer

The replacement disk was not initialized with an mdadm superblock before adding.

Answer

The /dev/md0 array is still in a clean state and does not need the disk yet.

Answer

The /dev/sdb1 partition is already part of another md array.

Question 7

An administrator creates a pod named 'webpod' containing two containers: 'nginx' and 'logger'. The goal is for the nginx container to access the logger container via hostname 'logger'. Which network configuration is required?

Accepted Answer

No special configuration; containers in a pod can communicate via container names.. In Kubernetes (and by extension, OpenShift, which is the focus of EX200), containers within the same Pod share the same network namespace. This means they can communicate with each other using localhost or, more commonly, the container name as a hostname, which is resolved via the Pod's internal DNS or /etc/hosts. No additional network configuration is required for inter-container communication within a Pod.

Answer

Use 'podman network create' and connect both containers to that network.

Answer

Set environment variable LOGGER_HOST in nginx container.

Answer

Create a network with --internal and --ip-range.

Question 8

Refer to the exhibit. A developer created this Containerfile to build a custom web server image. The build fails. Which TWO changes are necessary to make the Containerfile correct and allow the build to succeed?

Accepted Answer

Add a specific tag to the FROM line, e.g., ubi8/ubi:8.4. Option A is needed because the FROM line must specify a tag (e.g., ubi8/ubi:latest or a specific version) to avoid ambiguity. Option B is required because Red Hat Enterprise Linux 8 uses dnf instead of yum for package installation. Option C (EXPOSE 80) is not required to fix the build failure; it is documentation for port mapping. Option D (changing FROM to ubi9) is not necessary; the issue is the missing tag, not the base image version. Option E (adding COPY) already exists; an additional COPY is not needed to fix the build.

Answer

Change the FROM line to use ubi9/ubi (Red Hat Universal Base Image 9)

Answer

Add an EXPOSE 80 instruction before the CMD

Answer

Add a second COPY instruction to copy the container configuration files

Question 9

An administrator wants to run a container with --user 1001:1001 to avoid running as root. After starting, the container cannot write to a bind-mounted directory owned by root. What is the best practice to allow write access?

Accepted Answer

Use 'podman unshare chown 1001:1001 /host/dir' to change host directory ownership.. Option C is correct because `podman unshare chown 1001:1001 /host/dir` changes the ownership of the host directory to UID/GID 1001, matching the container's user. This is the best practice in rootless Podman environments, as it avoids running the container with elevated privileges while ensuring the container user can write to the bind-mounted directory.

Answer

Run the container with --privileged.

Answer

Add the user 1001 on the host to the root group.

Answer

Set setuid bit on the host directory.

Question 10

A container is running but cannot be accessed from the network. Which TWO commands could help diagnose the issue? (Select exactly two.)

Accepted Answer

podman port. Option B is correct because `podman port` lists the port mappings for a container, showing which host ports are mapped to container ports. If a container is running but unreachable from the network, this command reveals whether the expected port mapping exists and is correctly configured. Without a proper mapping, external traffic cannot reach the container's service.

Answer

podman logs

Answer

podman exec

Answer

podman top

Question 11

Based on the exhibit, what is the most likely cause of the error?

Accepted Answer

DNS resolution failure is preventing the registry hostname from being resolved.. Option C is correct because the error shows a DNS lookup failure (timeout on port 53). Option A would show connection refused. Option B would show timeout on port 443 or similar. Option D would show 'image not found'.

Answer

The container registry is unreachable due to a firewall blocking port 443.

Answer

The image name is invalid.

Answer

The container registry is unreachable due to a network outage.

Question 12

An administrator wants newly created files to be readable and writable only by the owner, and readable by group and others. Which umask value should be set?

Accepted Answer

022. A umask of 022 subtracts write permission for group and others from the default 666 (files) and 777 (directories), resulting in files with 644 permissions (owner read/write, group read, others read).

Answer

027

Answer

002

Answer

077

Question 13

A file has been assigned an incorrect SELinux context, preventing a service from accessing it. Which command restores the default SELinux context for that file?

Accepted Answer

restorecon. The 'restorecon' command restores the default SELinux security context as defined by the policy. 'chcon' changes context manually, 'setfiles' is for bulk relabeling, and 'fixfiles' is for comprehensive relabeling.

Answer

chcon

Answer

fixfiles

Answer

setfiles

Question 14

Refer to the exhibit. A CGI script located at /var/www/cgi-bin/test.cgi fails to execute. What is the most likely cause?

Accepted Answer

The SELinux context should be httpd_sys_script_exec_t.. CGI scripts require the httpd_sys_script_exec_t context to be executable by the web server. The current context httpd_sys_content_t is for static files only.

Answer

The script is in the wrong directory.

Answer

The script is not marked as executable.

Answer

The file permissions are incorrect.

Question 15

Refer to the exhibit. An administrator wants to add the HTTP service (port 80) to the internal zone permanently. Which sequence of commands should be used?

Accepted Answer

firewall-cmd --zone=internal --add-service=http --permanent; firewall-cmd --reload. To add a service permanently, use '--add-service' with '--permanent' and then reload firewalld to apply changes. The correct order is: firewall-cmd --zone=internal --add-service=http --permanent, then firewall-cmd --reload.

Answer

firewall-cmd --add-service=http --zone=internal; firewall-cmd --reload

Answer

firewall-cmd --permanent --add-service=http --zone=internal; systemctl restart firewalld

Answer

firewall-cmd --zone=internal --add-service=http; firewall-cmd --runtime-to-permanent