XK0-005 Scripting, Containers and Automation Practice Test 7 — 15 Questions

Question 1

A cron job runs a script that uses a command only available in a custom directory. The script fails from cron but works in the user's shell. Which of the following is the most common cause?

Accepted Answer

The cron job does not source the user's .bashrc. The most common cause is that cron jobs run in a minimal environment and do not source the user's shell initialization files like .bashrc. This means the custom directory containing the command is not in the PATH variable when the script executes under cron, even though it works in the user's interactive shell where .bashrc is sourced.

Answer

The script is not executable

Answer

The script has incorrect line endings

Answer

The cron job runs as root but command is in user's PATH

Question 2

A bash script uses a for loop to iterate over files in a directory. Which of the following correctly assigns each filename to the variable FILE?

Accepted Answer

for FILE in *.txt; do. Option B is correct because the shell expands the wildcard pattern `*.txt` into a list of matching filenames before the `for` loop executes, and each filename is assigned to the variable `FILE` in turn. This approach is safe and efficient because it avoids parsing the output of `ls`, which can break with filenames containing spaces or special characters.

Answer

for FILE in $(ls *.txt); do

Answer

for FILE in 'ls *.txt'; do

Answer

for FILE = *.txt; do

Question 3

A systemd timer unit is configured to run a service every hour but the service never executes. The timer shows as active and enabled. Which of the following is the most likely cause?

Accepted Answer

The service unit is masked. When a systemd timer unit is active and enabled but the associated service never executes, the most likely cause is that the service unit is masked. A masked unit is symlinked to /dev/null, which prevents systemd from starting it regardless of timer triggers. The timer itself runs correctly, but systemd silently ignores the request to activate the masked service.

Answer

The timer is not started

Answer

The service unit is not enabled

Answer

The timer unit has a mistake in the OnCalendar directive

Question 4

A container produces a large amount of log output to stdout. Which TWO methods effectively manage log size in a production environment?

Accepted Answer

Configure journald limits for container logging. Option B is correct because journald can be configured to limit the size of log data it stores, including container logs that are sent to the journal. In a production environment, setting `SystemMaxUse=` or `MaxRetentionSec=` in `/etc/systemd/journald.conf` prevents unbounded log growth. Option E is correct because Docker's `--log-opt max-size=10m` truncates the container's log file when it reaches 10 MB, rotating it automatically, which directly manages log size at the container runtime level.

Answer

Use docker logs --tail 100 to limit output

Answer

Use a bind mount to redirect logs to /dev/null

Answer

Configure the application inside the container to log to a file

Question 5

A container named web2 exited with status 0. Which of the following is the most likely reason?

Accepted Answer

The container was stopped manually with docker stop. Exit code 0 indicates a successful termination. When a container exits with status 0, it means the main process (entrypoint or command) completed its task without errors. Option C is correct because `docker stop` sends a SIGTERM signal to the container's PID 1, allowing it to shut down gracefully; if the process handles the signal and exits cleanly, the exit code will be 0.

Answer

The container ran a task and completed

Answer

The container's entrypoint crashed

Answer

The container ran out of memory

Question 6

The backup script above always outputs 'Backup failed' even when the tar command succeeds. Which of the following is the cause?

Accepted Answer

The correct variable is $? not &?. The script uses `&?` to reference the exit status of the `tar` command, but the correct shell variable is `$?`. The `$?` variable holds the exit code of the last executed command (0 for success, non-zero for failure). Using `&?` is a syntax error that results in an empty or invalid value, causing the `if` statement to always evaluate to false (or treat the condition as non-zero), thus always printing 'Backup failed'.

Answer

The tar command should use -czvf

Answer

The if statement syntax is wrong

Answer

The variable &? is not defined

Question 7

A container started with the above Compose configuration fails to set the system time (clock_settime syscall). Which additional capability is required?

Accepted Answer

SYS_TIME. The `clock_settime` syscall requires the `SYS_TIME` capability to modify the system clock. In Docker Compose, capabilities are added via the `cap_add` directive, and without `SYS_TIME`, the container lacks the privilege to change the system time, resulting in a failure.

Answer

SYS_NICE

Answer

SYS_RESOURCE

Answer

SYS_CLOCK

Question 8

A systems administrator writes a Bash script named 'backup.sh' and wants it to run with the Bash shell. Which line should appear first in the script?

Accepted Answer

#!/bin/bash. The shebang line `#!/bin/bash` is required as the first line to instruct the operating system to execute the script using the Bash shell interpreter located at `/bin/bash`. Without this line, the script may be run by a different shell (e.g., `/bin/sh`), leading to syntax or behavior differences. The shebang must start with `#!` followed by the absolute path to the interpreter.

Answer

# This is a bash script

Answer

#/bin/bash

Answer

#!/bin/sh

Question 9

An administrator needs to run a script '/usr/local/bin/cleanup.sh' every day at 2:30 AM. Which crontab entry is correct?

Accepted Answer

30 2 * * * /usr/local/bin/cleanup.sh. The correct crontab syntax is `minute hour day month weekday command`. Option D specifies minute 30, hour 2, and asterisks for all other fields, which means the script runs at 2:30 AM every day. This matches the requirement exactly.

Answer

2 30 * * * /usr/local/bin/cleanup.sh

Answer

*/30 2 * * * /usr/local/bin/cleanup.sh

Answer

30 * * * * /usr/local/bin/cleanup.sh

Question 10

A Docker container using port 8080 fails to start with the error 'port is already allocated'. Which command should the administrator use to identify the process using that port?

Accepted Answer

ss -tlnp. Option C is correct because the `ss -tlnp` command lists TCP listening sockets (`-l`) with numeric addresses (`-n`) and shows the process identifier (PID) and process name (`-p`) that owns each socket. This directly identifies which process has bound port 8080, allowing the administrator to resolve the 'port is already allocated' error.

Answer

ss -tan

Answer

ss -tln

Answer

ss -r

Question 11

After writing a script, the administrator cannot execute it with './script.sh'. The permissions are '-rw-rw-r--'. Which command makes the script executable?

Accepted Answer

chmod u+x script.sh. Option A is correct because the current permissions (`-rw-rw-r--`) show that the owner lacks execute permission. The command `chmod u+x script.sh` adds execute permission for the user (owner) only, which is the minimal and most secure way to make the script executable by the administrator who owns it. This directly addresses the requirement without granting unnecessary permissions to the group or others.

Answer

chmod +x script.sh

Answer

chmod g-x script.sh

Answer

chmod a+rwx script.sh

Question 12

An Ansible playbook includes the following task: 'ansible.builtin.service: name=nginx state=restarted'. However, the playbook fails with 'module not found'. What is the most likely cause?

Accepted Answer

The module name uses the wrong FQCN. The correct module is 'ansible.builtin.systemd_service'.. The error 'module not found' indicates that Ansible cannot locate the module specified in the task. The correct fully qualified collection name (FQCN) for the service module in the `ansible.builtin` collection is `ansible.builtin.service`, not `ansible.builtin.systemd_service`. The `systemd_service` module does not exist in the `ansible.builtin` collection; the correct module for managing systemd services is `ansible.builtin.systemd`, but the standard service module (`ansible.builtin.service`) works across init systems and is the appropriate choice here.

Answer

The playbook is not in the correct directory.

Answer

The target host does not have nginx installed.

Answer

The control node does not have Python installed.

Question 13

A DevOps engineer wants to reduce the size of a Docker image by combining build stages. Which Dockerfile feature should be used?

Accepted Answer

Multi-stage builds (multiple FROM statements). Multi-stage builds, implemented by using multiple FROM statements in a single Dockerfile, allow a DevOps engineer to copy only the necessary artifacts from intermediate build stages into the final image. This eliminates build-time dependencies, tools, and intermediate layers from the final image, significantly reducing its size without sacrificing build functionality.

Answer

RUN --mount=type=cache

Answer

Layer caching

Answer

Using a smaller base image like Alpine

Question 14

A script named 'test.sh' contains '#!/bin/bash' and is located in the current directory. Which command runs the script in the current shell environment without forking a subshell?

Accepted Answer

source test.sh. The `source` command (or its synonym `.`) executes the script in the current shell environment without forking a subshell. This is essential when you need the script to modify the current shell's environment, such as setting variables or changing directories, because a subshell would discard those changes upon exit.

Answer

./test.sh

Answer

sh test.sh

Answer

bash test.sh

Question 15

An administrator wants to run a script every Monday at 3:00 PM using a systemd timer. Which unit file configuration is correct for the timer?

Accepted Answer

OnCalendar=Mon *-*-* 15:00:00. Option A is correct because systemd timer units use the `OnCalendar=` directive with a calendar event format that follows `DayOfWeek Year-Month-Day Hour:Minute:Second`. The pattern `Mon *-*-* 15:00:00` specifies every Monday at 15:00:00, where the asterisks act as wildcards for any year, month, and day. This matches the requirement to run a script every Monday at 3:00 PM.

Answer

OnCalendar=weekly Monday 15:00

Answer

ExecStart=/usr/local/bin/script.sh

Answer

OnCalendar=daily 15:00