EX200 Practice Test 38 — 15 Questions

Question 1

A developer is running Podman as a non-root user on a Red Hat Enterprise Linux 8 system. The developer successfully runs a container, but notices that after logging out of the SSH session, the container stops. The developer wants the container to continue running even after disconnecting from the SSH session. The container is a simple web server that listens on port 8080. The developer has already enabled lingering for the user account using 'loginctl enable-linger'. However, the container still stops upon logout. What additional step should the developer take to ensure the container persists after logout?

Accepted Answer

Create a systemd user service by running 'podman generate systemd --new --name mywebcontainer' and then enable and start the service with 'systemctl --user enable --now container-mywebcontainer.service'. Option D is correct because even with lingering enabled, a container started directly via `podman run` is tied to the user's login session and will be terminated when the session ends. To make the container persist independently of the SSH session, it must be managed as a systemd user service. The `podman generate systemd --new` command creates a systemd unit file that can be enabled with `systemctl --user`, ensuring the container starts automatically and continues running after logout.

Answer

Add the --restart=always flag to the podman run command

Answer

Use podman run --detach to run the container in the background

Answer

Use podman run -d to run the container in detached mode

Question 2

A system administrator is troubleshooting a custom service called 'database.service' that fails intermittently. The service is a proprietary database that requires large amounts of memory. The administrator runs systemctl status database and sees 'Active: failed (Result: core-dump)' and the journal shows 'Out of memory: Killed process (database) total-vm:...' The server has 8GB RAM and 2 CPU cores. The service unit file does not contain any memory limits. The application is configured to use up to 4GB. The administrator suspects the systemd service is being killed by the OOM killer. Which action should the administrator take to prevent this issue?

Accepted Answer

Set OOMScoreAdjust=-1000 in the service unit file.. Option B is correct because setting OOMScoreAdjust=-1000 makes the systemd service less likely to be targeted by the OOM killer. The OOM killer selects processes based on a badness score; a lower score (down to -1000) reduces the likelihood of being killed. Since the service is already configured to use up to 4GB and the server has 8GB RAM, adjusting the OOM score is the targeted fix without disabling kernel protections or over-allocating resources.

Answer

Set MemoryMax=6G in the service unit file.

Answer

Modify kernel parameters to disable the OOM killer.

Answer

Increase swap space to 16GB.

Question 3

A junior system administrator configures rsyslog on a RHEL 9 server to forward logs to a remote centralized log server. They add the line *.* @192.168.1.100:514 to /etc/rsyslog.conf and restart rsyslog with systemctl restart rsyslog. Local logging works fine, but the remote server does not receive any logs. The administrator checks the local firewall and confirms that UDP port 514 is open outbound. They also verify network connectivity using nc. What is the most likely cause?

Accepted Answer

The SELinux boolean rsyslog_remote is disabled, blocking outbound syslog.. Option C is correct because on RHEL 9, SELinux enforces a targeted policy that blocks rsyslog from making outbound network connections by default. The boolean `rsyslog_remote` controls this behavior; when disabled, SELinux denies the outbound syslog traffic even though the local firewall allows it. The administrator must enable this boolean with `setsebool -P rsyslog_remote on` to allow rsyslog to forward logs via UDP or TCP.

Answer

The systemd unit for rsyslog is masked, preventing it from running.

Answer

The remote rsyslog server is not listening on UDP port 514.

Answer

The configuration should use @@ for TCP instead of @ for UDP.

Question 4

A Red Hat Enterprise Linux server has multiple network interfaces, and the administrator needs to ensure that the service 'httpd' starts automatically after a reboot. The administrator has already enabled the service using 'systemctl enable httpd', but after a reboot, the service is not running. The administrator checks the status and finds that the service is enabled but not started. The system uses systemd. Which additional step is required to ensure the service starts automatically at boot?

Accepted Answer

Check that the service's unit file has an [Install] section and is properly configured.. Option C is correct because for a service to start automatically at boot, its unit file must contain a properly configured [Install] section that defines the target (e.g., WantedBy=multi-user.target). Running 'systemctl enable httpd' creates the necessary symlinks only if the [Install] section is present. Without it, 'systemctl enable' may succeed silently but no symlinks are created, so the service is marked as enabled but never started by systemd at boot.

Answer

Set the service to be started by the network target using systemctl add-wants.

Answer

Run systemctl start httpd after enabling it.

Answer

Create a symlink in /etc/rc.d/rc3.d/ for the service.

Question 5

A system administrator at a company is configuring a new storage array for a file server. The server uses LVM on top of a hardware RAID5 array. The administrator has created a volume group "vg_data" and a logical volume "lv_docs" intended for an XFS filesystem. After formatting with mkfs.xfs and mounting to /docs, the system works. However, after a reboot, the mount point is empty and the logical volume is not mounted. The administrator checks /etc/fstab and finds an entry using the device path /dev/vg_data/lv_docs. What is the most likely cause?

Accepted Answer

The volume group is not activated during boot because the LVM service is not enabled. Option D is correct because LVM volume groups are not automatically activated during boot unless the lvm2-lvmetad service (or equivalent LVM service) is enabled. Without this service, the system does not scan for and activate volume groups, so logical volumes like /dev/vg_data/lv_docs are not available for mounting. The /etc/fstab entry using the device path fails silently, leaving /docs empty.

Answer

The mount point /docs was deleted during reboot

Answer

The XFS filesystem was corrupted during reboot

Answer

The logical volume name is misspelled in /etc/fstab

Question 6

A Red Hat Enterprise Linux system has a second disk /dev/sdb with a single partition /dev/sdb1 that was formatted as XFS and mounted at /mnt/backup. The administrator wants to change the filesystem on /dev/sdb1 to ext4 without losing existing data. Which steps should be taken in order?

Accepted Answer

Backup data, unmount, mkfs.ext4, remount, restore data. Option D is correct because you cannot convert an XFS filesystem to ext4 in place; the only safe method is to back up the data, unmount the partition, create a new ext4 filesystem with mkfs.ext4, remount, and then restore the data. XFS and ext4 have fundamentally different on-disk structures (e.g., allocation groups vs. block groups, different journaling formats), so no in-place conversion tool exists.

Answer

Unmount, mkfs.ext4 /dev/sdb1, then mount

Answer

Use xfs_admin to change type

Answer

Use fsck.ext4 to convert in place

Question 7

An administrator needs to create a new 500MB swap partition on a disk that already has an extended partition. The disk /dev/sda has partitions: /dev/sda1 (primary, /boot), /dev/sda2 (extended), /dev/sda5 (logical, swap, 2GB). The administrator wants to add another swap partition, but fdisk shows no free space. Which approach should be used?

Accepted Answer

Use a file-based swap file. Option B is correct because the disk has no free space (the extended partition consumes all remaining space after /dev/sda1, and logical partitions are contained within it). Adding a swap file is the simplest and safest approach: it does not require repartitioning, works with any filesystem, and is fully supported by systemd and swapon. The administrator can create a 500MB file, format it as swap with mkswap, and enable it with swapon.

Answer

Use LVM to create a logical volume for swap

Answer

Shrink the filesystem on /dev/sda1 to create free space

Answer

Delete /dev/sda5 and recreate it with larger size

Question 8

During a system audit, an administrator finds that a filesystem mounted at /srv/data with ext4 is not showing in /etc/fstab. Further investigation reveals that the underlying device is an LVM logical volume lv_data in vg_data. The administrator wants to ensure the filesystem is mounted at boot. He adds an entry to /etc/fstab using the device path /dev/vg_data/lv_data. On reboot, the system fails to mount the filesystem and enters emergency mode. The logical volume and filesystem are intact. What is the most likely reason for the failure?

Accepted Answer

The device path /dev/vg_data/lv_data is a symlink that may not be available; use /dev/mapper/vg_data-lv_data or UUID.. The device path /dev/vg_data/lv_data is a symbolic link created by LVM that may not be available early in the boot process because the device mapper nodes are not yet created. The correct approach is to use the stable /dev/mapper/vg_data-lv_data path or the filesystem UUID in /etc/fstab to ensure reliable mounting at boot.

Answer

The mount point /srv/data does not exist.

Answer

The filesystem type specified in fstab is incorrect.

Answer

The logical volume is not activated at boot because lvm2-lvmetad is not running.

Question 9

An admin is setting up a new RHEL 9 server. He has two disks: /dev/sda (500GB) and /dev/sdb (500GB). He wants to create a 300GB logical volume for application data, with the ability to take snapshots. He decides to use LVM thin provisioning. He creates a physical volume on /dev/sda, a volume group vg_data, and a thin pool with 300GB of data space and 10GB metadata. He then creates a thin volume lv_app of 300GB. Later, he wants to extend lv_app to 400GB as usage increases. He runs 'lvextend -L+100G /dev/vg_data/lv_app'. The command succeeds, but the application reports no additional space. What is the likely issue?

Accepted Answer

He forgot to resize the filesystem (e.g., xfs_growfs or resize2fs).. Option D is correct because when extending a thin volume, the underlying logical volume is extended, but the filesystem on top of it does not automatically grow. The admin must run a filesystem-specific command like xfs_growfs (for XFS) or resize2fs (for ext4) to make the additional space available to the application. Without this step, the filesystem remains at its original size, so the application sees no change.

Answer

The thin pool has insufficient free space to accommodate the extension.

Answer

The thin volume must be unmounted to extend.

Answer

He should have used lvextend with the --resizefs option.

Question 10

A junior admin receives a ticket: 'The /var partition is filling up quickly. The server has an extra 100GB disk /dev/sdb. The /var filesystem is on logical volume lv_var in volume group vg_system. Currently, vg_system has no free extents. The admin's plan: create a new physical volume on /dev/sdb, extend vg_system, extend lv_var, and resize the filesystem. He runs: pvcreate /dev/sdb; vgextend vg_system /dev/sdb; lvextend -L+100G /dev/vg_system/lv_var; resize2fs /dev/vg_system/lv_var. The system reports error: 'resize2fs: Invalid argument while trying to open /dev/vg_system/lv_var'. What is the most likely mistake?

Accepted Answer

He used resize2fs instead of xfs_growfs because /var is typically XFS.. Option D is correct because the error 'resize2fs: Invalid argument while trying to open /dev/vg_system/lv_var' indicates that the filesystem on lv_var is not ext2/3/4 but likely XFS. RHEL 8/9 defaults to XFS for /var, and XFS requires xfs_growfs (which operates on a mount point, not a block device) instead of resize2fs. Using resize2fs on an XFS filesystem produces this exact error.

Answer

He should have used lvresize instead of lvextend.

Answer

He forgot to run partprobe after pvcreate.

Answer

The lvextend command failed because vg_system has no free extents.

Question 11

A production server runs RHEL 8 with a software RAID 5 array (/dev/md0) composed of three disks: /dev/sda, /dev/sdb, /dev/sdc. The array is used to store database files. The server experiences a disk failure on /dev/sdc. The admin replaces /dev/sdc with an identical disk and wants to rebuild the array. He runs: mdadm /dev/md0 --add /dev/sdc. The command completes without error, but the array shows a degraded state after several hours. What should the admin do next?

Accepted Answer

Run mdadm --detail /dev/md0 to check the status and rebuild progress.. Option A is correct because after adding a replacement disk to a RAID 5 array, the rebuild process begins automatically but may take hours depending on disk size and I/O load. Running `mdadm --detail /dev/md0` allows the admin to check the current state, rebuild progress (e.g., percentage complete), and any errors that might have stalled the rebuild. This is the first diagnostic step to determine if the rebuild is still ongoing, has failed, or is degraded for another reason.

Answer

Rebuild will happen automatically; just wait longer.

Answer

Recreate the array using mdadm --create with the same parameters.

Answer

Format /dev/sdc with a filesystem before adding to the array.

Question 12

A company runs a critical web application in a container on a Red Hat Enterprise Linux 9 server. The container is started via a systemd service called 'webapp.service'. The service unit file was generated using 'podman generate systemd --new --name webapp'. Recently, after a kernel update and reboot, the service fails to start the container. The administrator runs 'systemctl status webapp.service' and sees 'Active: failed (Result: exit-code)' and 'Process: 1234 ExecStart=/usr/bin/podman run ... (code=exited, status=125)'. The administrator also checks 'journalctl -u webapp.service' and sees: 'Error: unable to start container: container create failed: OCI runtime error: container_linux.go:380: starting container process caused: exec: "/usr/bin/app.sh": stat /usr/bin/app.sh: no such file or directory'. The container image was built locally using a Containerfile that includes 'COPY app.sh /usr/bin/app.sh'. The administrator verifies the image is present locally. What should the administrator do to resolve this issue?

Accepted Answer

Rebuild the container image using 'podman build -t webapp .' to ensure the app.sh file is included, then restart the service.. Option D is correct because the error indicates that the container image is missing the `/usr/bin/app.sh` file, even though the `COPY` instruction was in the Containerfile. The most likely cause is that the image was built before the `app.sh` script was added to the build context, or the build was incomplete. Rebuilding the image with `podman build -t webapp .` ensures the file is properly included in the image layers, resolving the OCI runtime error.

Answer

Disable SELinux with setenforce 0 and restart the service.

Answer

Remove the systemd service and regenerate it with 'podman generate systemd --new --name webapp'.

Answer

Manually create the /usr/bin/app.sh file inside the container using podman exec.

Question 13

A junior administrator is tasked with setting up SELinux contexts on a Red Hat Enterprise Linux 9 server to allow Apache HTTPD to read and write to a custom directory /var/www/customcontent. The directory already exists and contains several files. The administrator has confirmed that the httpd service is running and SELinux is in enforcing mode. After changing the context to httpd_sys_content_t using chcon, the web server can read files but cannot write to the directory. The administrator needs to fix this without disabling SELinux or changing the mode to permissive. Which of the following is the correct next step?

Accepted Answer

Run restorecon -R -v /var/www/customcontent after setting the default context with semanage fcontext -a -t httpd_sys_rw_content_t '/var/www/customcontent(/.*)?'. The directory already has the httpd_sys_content_t type, which allows reading but not writing. To enable write access, the correct type is httpd_sys_rw_content_t. Option B correctly uses semanage fcontext to set the default context to this type and then runs restorecon to apply it persistently, ensuring Apache can both read and write.

Answer

Set the SELinux boolean httpd_enable_homedirs to on using setsebool.

Answer

Change the context to httpd_sys_content_t using chcon -R -t httpd_sys_content_t /var/www/customcontent

Answer

Run semanage fcontext -a -t httpd_sys_rw_content_t '/var/www/customcontent(/.*)?' without running restorecon.

Question 14

You are managing a Red Hat Enterprise Linux 9 server that hosts a critical database application. The database stores its data on an XFS filesystem mounted on /data, backed by a logical volume in a volume group named vg_db. Recently, the database team reported that write operations are failing with 'Disk quota exceeded' errors, but the filesystem still shows 40% free space. You check the filesystem quota configuration and find that no user or group quotas are set on /data. The database runs as user 'dbadmin' with group 'dba'. Which of the following is the most likely cause of the 'Disk quota exceeded' error?

Accepted Answer

An XFS project quota is configured on the /data directory, limiting the space used by the database files.. Option B is correct because XFS project quotas can limit the total space used by a directory tree, regardless of the user or group that owns the files. Even though no user or group quotas are set, a project quota on /data restricts the database files, causing 'Disk quota exceeded' errors despite 40% free space on the filesystem.

Answer

The logical volume is thin provisioned and the data pool is full.

Answer

SELinux is blocking the database writes due to a denial.

Answer

The filesystem has run out of inodes.

Question 15

A company has a RHEL 9 server that hosts a critical application. The server has two network interfaces: enp1s0 (192.168.1.100/24) and enp2s0 (10.0.0.100/24). The default gateway is 192.168.1.1. The application listens on a TCP port 8080 and should be accessible from both networks. Recently, the administrator noticed that clients on the 10.0.0.0/24 network can ping the server's 10.0.0.100 address but cannot connect to port 8080. Clients on 192.168.1.0/24 can connect fine. The firewall is configured with the default zone (public) and the service 'http' is allowed, but port 8080 is not specifically allowed. The administrator checks 'firewall-cmd --list-all' and sees that only services 'ssh' and 'http' are listed. The application is running and listening on 0.0.0.0:8080. What is the most likely cause and the correct course of action?

Accepted Answer

Add a firewall rule to open TCP port 8080 in the public zone using 'firewall-cmd --add-port=8080/tcp --permanent' and reload.. The firewall is blocking incoming connections to port 8080 because only services 'ssh' (port 22) and 'http' (port 80) are allowed in the public zone. Since the application listens on 0.0.0.0:8080, it is reachable from both networks at the IP level, but the firewall drops packets destined for port 8080. Adding a permanent rule to open TCP port 8080 and reloading the firewall configuration resolves the issue.

Answer

Disable SELinux to allow the application to accept connections.

Answer

Change the application to listen only on the 10.0.0.100 interface.

Answer

Add a static route for the 10.0.0.0/24 network via the 10.0.0.1 gateway.