XK0-006 Practice Test 18 — 15 Questions

Question 1

An administrator needs to deploy a set of microservices using Docker Compose. The services require configuration values that vary between development and production environments. Which approach allows the administrator to override values without modifying the docker-compose.yml file?

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

Accepted Answer

Use multiple compose files with the -f flag: docker-compose -f docker-compose.yml -f docker-compose.prod.yml up.. Docker Compose supports merging multiple compose files via the -f flag, where later files override or extend values from earlier ones. Running docker-compose -f docker-compose.yml -f docker-compose.prod.yml up applies the base configuration and then overlays production-specific values without editing the original file.

Answer

Define multiple services in one docker-compose.yml and use profiles.

Answer

Use environment variables in the Dockerfile and pass them via docker run -e.

Answer

Use the extends keyword in docker-compose.yml.

Question 2

A Kubernetes administrator needs to expose a deployment named 'webapp' as a service accessible externally on port 80. Which kubectl command should be used?

Accepted Answer

kubectl expose deployment webapp --type=NodePort --port=80. The kubectl expose deployment command creates a Service from an existing Deployment. Specifying --type=NodePort makes the service externally reachable on each node's IP at a high port, and --port=80 sets the service port to 80. This is the standard imperative way to expose a deployment externally without writing a YAML manifest.

Answer

kubectl port-forward deployment/webapp 80:80

Answer

kubectl run webapp --port=80

Answer

kubectl create service clusterip webapp --port=80

Question 3

After using 'apt-get install' to install several packages, the administrator notices that disk space is low. Which command cleans up the package cache?

Accepted Answer

apt-get clean. The 'apt-get clean' command removes all package files (.deb) from the local cache located in /var/cache/apt/archives/. This frees up disk space without affecting installed packages, as the cache is only used for future installations or reinstallations. It is the correct command to clean up the package cache after installations.

Answer

apt-get purge

Answer

apt-get autoremove

Answer

apt-get remove

Question 4

A Linux server is experiencing slow boot times. The administrator wants to identify which systemd services are taking the longest to start. Which command should be used?

Accepted Answer

systemd-analyze blame. The `systemd-analyze blame` command prints a list of all running systemd units, sorted by the time they took to initialize during boot. This directly answers the administrator's need to identify which services are causing slow boot times by showing the exact startup duration for each unit.

Answer

systemd-analyze time

Answer

journalctl -b -p 3

Answer

systemctl list-units --all

Question 5

A containerized application is consuming excessive memory on a Linux host running Podman. Which command sets a memory limit of 512 megabytes when running a container?

Accepted Answer

podman run --memory=512m myimage. Podman uses the `--memory` flag (identical to Docker's syntax) to set a hard memory limit on a container. The value `512m` specifies 512 megabytes. This directly restricts the container's memory usage via cgroups, preventing it from consuming excessive host memory.

Answer

podman run --limit-memory 512 myimage

Answer

podman run --mem=512m myimage

Answer

podman run --memory-limit=512MB myimage

Question 6

A Linux administrator needs to locate all files in /var/log that were modified more than 7 days ago. Which command should be used?

Accepted Answer

find /var/log -mtime +7. The find command with -mtime +7 finds files modified more than 7 days ago. locate uses a database and does not support -mtime; grep is for text search; ls does not filter by modification time.

Answer

grep -mtime +7 /var/log

Answer

ls -mtime +7 /var/log

Answer

locate -mtime +7 /var/log

Question 7

A security analyst wants to ensure that users cannot change their password more than once every 7 days. Which command and option should be used to enforce this policy for user 'jsmith'?

Accepted Answer

chage -m 7 jsmith. The `chage -m 7 jsmith` command sets the minimum number of days required between password changes for user jsmith to 7 days. The `-m` option of `chage` specifically controls the minimum password age, preventing the user from changing their password more than once every 7 days.

Answer

usermod -e 7 jsmith

Answer

chage -M 7 jsmith

Answer

passwd -n 7 jsmith

Question 8

A process with PID 2345 is not responding. The administrator wants to force stop the process immediately. Which command should be used?

Accepted Answer

kill -9 2345. SIGKILL (signal 9) forcefully terminates a process. kill -9 2345 sends SIGKILL to PID 2345.

Answer

kill -1 2345

Answer

pkill -15 -f processname

Answer

kill -15 2345

Question 9

A server running nftables has a rule set that allows incoming SSH from the management network (192.168.1.0/24). An administrator needs to insert a rule to drop SSH from all other sources. Which nft command accomplishes this? Assume the input chain is 'input' and the table is 'inet filter'.

Accepted Answer

nft add rule inet filter input ip saddr != 192.168.1.0/24 tcp dport 22 drop. The correct rule uses 'nft add rule' with a source address negation (ip saddr != 192.168.1.0/24) matching TCP destination port 22 and a drop verdict, which precisely drops SSH from every source outside the management network while leaving the existing allow rule intact. This is the only option that combines the correct match criteria (source negation plus SSH port) with the drop action.

Answer

nft insert rule inet filter input tcp dport 22 drop

Answer

nft replace rule inet filter input handle 1 tcp dport 22 drop

Answer

nft add rule inet filter input tcp dport 22 accept

Question 10

A system administrator is troubleshooting a network issue where a server cannot reach the internet. The server's IP address is 192.168.1.10/24, and the default gateway is 192.168.1.1. Which command should be used to verify the default gateway configuration?

Accepted Answer

ip route show. The `ip route show` command displays the kernel's IPv4 routing table, which includes the default gateway entry (destination 0.0.0.0/0 via 192.168.1.1). This directly verifies whether the default gateway is configured correctly for the server to reach external networks.

Answer

ip neigh show

Answer

ip addr show

Answer

ip link show

Question 11

A technician needs to search a log file for lines containing either 'ERROR' or 'FATAL' and display the line numbers. Which command accomplishes this?

Accepted Answer

grep -n -E 'ERROR|FATAL' logfile. grep -n -E 'ERROR|FATAL' logfile uses extended regex with alternation and -n for line numbers. -i ignores case, but the stem does not mention case-insensitive; -v inverts match; -r is recursive.

Answer

grep -v -E 'ERROR|FATAL' logfile

Answer

grep -r -n 'ERROR|FATAL' logfile

Answer

grep -i 'ERROR|FATAL' logfile

Question 12

An administrator wants to run a script on multiple remote servers using Ansible. The script requires a variable that differs per host. Where should the administrator define this variable to follow best practices?

Accepted Answer

In host_vars/.yml. Ansible best practice is to define host-specific variables in host_vars/.yml, where the filename matches the inventory hostname. This keeps per-host configuration separate from the playbook and inventory, making it easy to maintain, version-control, and override at the appropriate precedence level. Variables defined here automatically apply only to that host, which is exactly what the scenario requires.

Answer

In the playbook under vars:

Answer

In the inventory file as a variable

Answer

In group_vars/all.yml

Question 13

After a kernel update, loading a proprietary kernel module fails with 'Invalid module format'. The module was built from source against the previous kernel. What is the most likely cause?

Accepted Answer

Module was not rebuilt for the new kernel version. The 'Invalid module format' error occurs when a kernel module's version magic string does not match the running kernel's version. Since the module was built against the previous kernel, it contains version information for that older kernel, and the new kernel rejects it as incompatible. Rebuilding the module against the new kernel's headers resolves this mismatch.

Answer

Module is not signed while Secure Boot is enabled

Answer

Module file permissions are incorrect

Answer

SELinux is blocking the module load

Question 14

Which TWO commands can be used to display the amount of free and used memory on a Linux system?

Accepted Answer

free -h. Option C, free -h, is correct because the free command reads memory statistics from /proc/meminfo and displays total, used, free, shared, buff/cache, and available RAM (and swap) in human-readable units with -h. Option D, cat /proc/meminfo, is correct because /proc/meminfo is the kernel-provided virtual file that exposes detailed memory counters such as MemTotal, MemFree, MemAvailable, Buffers, and Cached, so displaying it directly shows free and used memory. Option A, df -h, is wrong because df reports filesystem disk space usage, not RAM. Option B, du -sh, is wrong because du estimates file and directory disk usage. Option E, iostat, is wrong because it reports CPU and block-device I/O statistics, not memory usage.

Answer

df -h

Answer

du -sh

Answer

iostat

Question 15

A system administrator is tuning a server for a high-performance computing workload and needs to disable NUMA (Non-Uniform Memory Access) at boot to improve memory access latency. Which kernel boot parameter should be added to the GRUB_CMDLINE_LINUX line in /etc/default/grub?

Accepted Answer

numa=off. The `numa=off` kernel boot parameter explicitly disables NUMA support in the Linux kernel, forcing memory to be treated as a single contiguous block (UMA). This eliminates the latency penalty of remote memory accesses, which is beneficial for high-performance computing workloads that require consistent, low-latency memory access across all CPUs.

Answer

maxcpus=1

Answer

acpi=off

Answer

noapic