XK0-006 Practice Test 27 — 15 Questions

Question 1

A user reports they cannot log in after three failed password attempts. The system uses PAM with pam_faillock. Which command can the administrator use to view the number of failed attempts for the user?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

faillock --user username. The faillock command is the standard tool for viewing and managing failed login attempts when using pam_faillock. Running 'faillock --user username' displays the number of failed attempts and the timestamps for the specified user. This directly answers the question.

Answer

ausearch -m USER_LOGIN -ui username

Answer

pam_tally2 --user username

Answer

lastb username

Question 2

Which TWO commands can be used to check disk space usage on a Linux system?

Accepted Answer

du. The `du` command (option C) is correct because it estimates file space usage by recursively summing the sizes of files and directories, typically reporting in blocks or with `-h` for human-readable output, making it ideal for checking how much disk space specific directories consume. The `df` command (option E) is also correct because it reports filesystem-level disk space usage, showing total, used, and available space per mounted filesystem, which is the standard way to check overall disk capacity. Option A, `mount`, only lists mounted filesystems and their mount points and does not report space usage. Option B, `lsof`, lists open files and the processes using them, which is unrelated to disk space accounting. Option D, `fdisk`, is a partitioning tool for creating and modifying disk partitions and does not report space usage.

Answer

mount

Answer

lsof

Answer

fdisk

Question 3

Which command will run a container in detached mode with the name 'web' and map host port 8080 to container port 80, using the nginx image?

Accepted Answer

docker run -d --name web -p 8080:80 nginx. `docker run` creates and starts a new container. The `-d` flag runs it in detached mode (background), `--name web` assigns the name 'web', `-p 8080:80` maps host port 8080 to container port 80, and `nginx` specifies the image to use. This is the standard syntax for deploying a container with port mapping and a custom name.

Answer

docker exec -d --name web -p 8080:80 nginx

Answer

docker start -d --name web -p 8080:80 nginx

Answer

docker run -it --name web -p 8080:80 nginx

Question 4

A system administrator needs to install a package from a local RPM file without resolving dependencies automatically. Which command should be used?

Accepted Answer

rpm -i package.rpm. The `rpm -i package.rpm` command installs the specified RPM package without automatically resolving dependencies. The `-i` flag stands for 'install' and, unlike `-U` (upgrade) or higher-level tools like `yum` or `dnf`, it does not attempt to fetch or satisfy missing dependencies from configured repositories. This is the correct choice when the requirement is to install a local RPM file while explicitly avoiding automatic dependency resolution.

Answer

rpm -U package.rpm

Answer

yum localinstall package.rpm

Answer

dnf install ./package.rpm

Question 5

A security policy requires that user passwords must expire every 90 days. Which command can enforce this policy for user 'jsmith'?

Accepted Answer

chage -M 90 jsmith. The `chage -M 90 jsmith` command sets the maximum number of days a password is valid for user 'jsmith' to 90, which enforces the 90-day expiration policy. The `-M` option directly modifies the `PASS_MAX_DAYS` field in `/etc/shadow`, and `chage` is the standard tool for managing password aging on Linux systems.

Answer

usermod -e 90 jsmith

Answer

passwd -x 90 jsmith

Answer

chfn -f 90 jsmith

Question 6

A technician needs to kill a process with PID 1234 that is not responding to normal termination. Which command sends SIGKILL?

Accepted Answer

kill -9 1234. kill -9 sends SIGKILL, which forcefully terminates the process.

Answer

kill 1234

Answer

kill -15 1234

Answer

kill -1 1234

Question 7

Which of the following directories in the Filesystem Hierarchy Standard (FHS) contains variable data files such as logs, spool files, and temporary files that persist across reboots?

Accepted Answer

/var. /var is for variable data like logs, spool, and temporary files that persist. /tmp is for temporary files that may be cleared on reboot. /etc is for configuration files. /opt is for optional add-on software.

Answer

/opt

Answer

/etc

Answer

/tmp

Question 8

An administrator needs to run a container using a specific user ID to match host file permissions. Which Docker option should be used when running the container?

Accepted Answer

-u 1001. The `-u` (or `--user`) option in Docker allows you to run the container process with a specific user ID (UID) instead of the default root (UID 0). By specifying `-u 1001`, the container's main process will run as UID 1001, which can be matched to a host user's UID to ensure proper file ownership and permissions when accessing mounted volumes. This is essential for avoiding permission denied errors when the container writes files to a bind-mounted host directory.

Answer

-e USER=1001

Answer

-v /host:/container

Answer

--name mycontainer

Question 9

A user reports that they cannot access a website by domain name but can access it by IP address. Which of the following is the most likely cause?

Accepted Answer

DNS resolution problem. The user can access the website by IP address but not by domain name, which directly indicates that the system is unable to resolve the domain name to its corresponding IP address. This is a classic symptom of a DNS resolution problem, where the DNS client cannot query a DNS server or the DNS server fails to return the correct A or AAAA record. The fact that the web server is reachable by IP confirms that network connectivity and the web service itself are functioning correctly.

Answer

Web server is down

Answer

Firewall blocking port 80

Answer

Incorrect default gateway

Question 10

An administrator needs to configure SELinux to allow the Apache HTTP server to connect to a database server. Which SELinux boolean should be enabled?

Accepted Answer

httpd_can_network_connect_db. The SELinux boolean `httpd_can_network_connect_db` specifically allows the Apache HTTP server to make outbound TCP connections to database servers (e.g., MySQL, PostgreSQL). This is required when a web application needs to query a remote database. The other booleans control different aspects of httpd's behavior and do not grant network connectivity to databases.

Answer

httpd_can_network_connect

Answer

httpd_enable_cgi

Answer

httpd_use_nfs

Question 11

A developer is writing a shell script that needs to handle errors. Which THREE of the following are best practices for robust script error handling?

Accepted Answer

Check the exit code of commands using $?. Checking the exit code of commands using `$?` allows the script to conditionally handle failures based on the specific return value of each command. This is a fundamental error-handling technique in shell scripting, as every command returns an exit code (0 for success, non-zero for failure), and inspecting `$?` immediately after a command lets the developer decide how to respond to that specific error.

Answer

Ignore errors to simplify the script

Answer

Use set +e to allow the script to continue on error

Question 12

A system administrator notices that a web server is running but users cannot connect to port 443. Which ss command will show if the server is listening on that port?

Accepted Answer

ss -tlnp. The ss command with -tlnp shows TCP sockets (-t), in listening state (-l), with numeric ports (-n), and the owning process (-p). That combination directly answers whether anything is bound to TCP 443 and which process holds it. This is the standard diagnostic for a web server that is running but unreachable on its expected port.

Answer

ss -s

Answer

ss -tuln

Answer

ss -tan

Question 13

The system is experiencing slow disk I/O. Based on the exhibit, which step should the administrator take to improve performance?

Accepted Answer

Add the 'noatime' mount option in /etc/fstab. The 'noatime' mount option disables updating the access time (atime) on every file read, which eliminates a significant source of metadata write operations. Since the exhibit indicates slow disk I/O, reducing unnecessary writes directly improves performance by freeing I/O bandwidth for actual data transfers. This is a standard, low-risk optimization for workloads where access timestamps are not required.

Answer

Increase the filesystem block size

Answer

Enable write-back caching on the drive using hdparm

Answer

Change the I/O scheduler to 'deadline'

Question 14

A company is deploying a new web application using Docker containers. The application requires configuration values that vary between environments (development, staging, production). Which approach ensures the configuration is securely managed and applied without modifying the container image?

Accepted Answer

Pass configuration via environment variables and use Docker secrets for sensitive data.. Docker supports passing configuration via environment variables at runtime without altering the image, and Docker secrets securely manage sensitive data (e.g., passwords, API keys) by storing them in encrypted memory and mounting them as temporary files in `/run/secrets/`. This decouples configuration from the immutable image, adhering to the twelve-factor app methodology and ensuring environment-specific values are applied without rebuilding.

Answer

Build separate images for each environment with the configuration baked in.

Answer

Store configuration in a JSON file within the base image and override it at runtime.

Answer

Use a Dockerfile to copy the configuration file from the host at build time.

Question 15

A technician wants to create a symbolic link in /usr/local/bin that points to /opt/myapp/bin/start.sh. The technician has write permissions to /usr/local/bin. Which command should be used?

Accepted Answer

ln -s /opt/myapp/bin/start.sh /usr/local/bin/start.sh. ln -s target linkname creates a symbolic link. The target should be the file to link to, and the link name is the new symlink.

Answer

ln -s /usr/local/bin/start.sh /opt/myapp/bin/start.sh

Answer

ln /opt/myapp/bin/start.sh /usr/local/bin/start.sh

Answer

cp -s /opt/myapp/bin/start.sh /usr/local/bin/start.sh