systemd service for auto-start in Raspberry Pi - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the service description in a systemd service file.

Raspberry Pi

[Unit]
Description=[1]

Drag options to blanks, or click blank then click option'

AStart Service

BRaspberry Service

CService Auto

DAuto-start Raspberry Pi Service

Attempts:

3 left

💡 Hint

Common Mistakes

Using vague or incomplete descriptions.

Leaving the Description field empty.

The Description field should clearly describe the service purpose. "Auto-start Raspberry Pi Service" is clear and descriptive.

2fill in blank

medium

Complete the code to specify the command to start the service in the [Service] section.

Raspberry Pi

[Service]
ExecStart=[1]

Drag options to blanks, or click blank then click option'

A/usr/bin/python3 /home/pi/myscript.py

B/bin/start /home/pi/myscript.py

C/home/pi/myscript.py

Dpython /home/pi/myscript.py

Attempts:

3 left

💡 Hint

Common Mistakes

Not specifying the full path to the Python interpreter.

Omitting the interpreter and only giving the script path.

The ExecStart must specify the full path to the executable and the script. Using /usr/bin/python3 /home/pi/myscript.py is correct.

3fill in blank

hard

Fix the error in the [Install] section to enable the service to start at boot.

Raspberry Pi

[Install]
WantedBy=[1]

Drag options to blanks, or click blank then click option'

Aboot.target

Bdefault.target

Cmulti-user.target

Dstartup.target

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent or incorrect target names.

Using default.target which may not always work as expected.

The multi-user.target is the standard target for systemd services that start after boot and network are ready.

4fill in blank

hard

Fill both blanks to create a simple systemd service file that runs a script at startup.

Raspberry Pi

[Unit]
Description=[1]

[Service]
ExecStart=[2]

Drag options to blanks, or click blank then click option'

AAuto-start Raspberry Pi Service

B/usr/bin/python3 /home/pi/myscript.py

C/bin/bash /home/pi/start.sh

DRaspberry Pi Startup Script

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping description and ExecStart values.

Using incomplete commands in ExecStart.

The Description should describe the service, and ExecStart should specify the full command to run the script.

5fill in blank

hard

Fill all three blanks to complete a systemd service file that auto-starts a Python script on Raspberry Pi.

Raspberry Pi

[Unit]
Description=[1]
After=network.target

[Service]
ExecStart=[2]
Restart=always

[Install]
WantedBy=[3]

Drag options to blanks, or click blank then click option'

AAuto-start Raspberry Pi Service

B/usr/bin/python3 /home/pi/myscript.py

Cmulti-user.target

Ddefault.target

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect targets in WantedBy.

Not specifying Restart=always to keep the service running.

Omitting the After=network.target line.

This service file describes the service, runs the Python script with full path, restarts it if it stops, and enables it to start at the multi-user target.

Practice

1. What is the main purpose of creating a systemd service on a Raspberry Pi?

easy

A. To update the Raspberry Pi operating system

B. To manually run a program only once

C. To make a program start automatically when the Raspberry Pi boots

D. To uninstall software from the Raspberry Pi

Solution

1. Step 1: Understand systemd service purpose

   A systemd service is designed to manage programs and make them start automatically during boot.

2. Step 2: Identify the correct use case

   Starting a program automatically on boot matches the purpose of systemd services.

3. Final Answer:

   To make a program start automatically when the Raspberry Pi boots -> Option C

4. Quick Check:

   systemd service = auto-start program [OK]

Hint: Remember: systemd services auto-start programs on boot [OK]

Common Mistakes:

• Confusing systemd with manual program execution
• Thinking systemd updates the OS
• Believing systemd uninstalls software

2. Which of the following is the correct section header in a systemd service file to define the program to run?

easy

A. [Service]

B. [Unit]

C. [Install]

D. [Program]

Solution

1. Step 1: Recall systemd service file structure

   A systemd service file has three main sections: [Unit], [Service], and [Install].

2. Step 2: Identify where the program command goes

   The program to run is specified under the [Service] section using ExecStart.

3. Final Answer:

   [Service] -> Option A

4. Quick Check:

   Program command in [Service] section [OK]

Hint: Program command is always under [Service] section [OK]

Common Mistakes:

• Using [Unit] or [Install] for program commands
• Assuming [Program] is a valid section
• Confusing section headers

3. Given this systemd service file snippet:

[Unit]
Description=My Script

[Service]
ExecStart=/home/pi/myscript.sh

[Install]
WantedBy=multi-user.target

What command should you run to make this service start automatically on boot?

medium

A. sudo systemctl start myscript.service

B. sudo systemctl enable myscript.service

C. sudo systemctl reload myscript.service

D. sudo systemctl stop myscript.service

Solution

1. Step 1: Understand difference between start and enable

   Starting runs the service now; enabling sets it to run on boot.

2. Step 2: Identify command to auto-start on boot

   Use sudo systemctl enable myscript.service to enable auto-start.

3. Final Answer:

   sudo systemctl enable myscript.service -> Option B

4. Quick Check:

   Enable = auto-start on boot [OK]

Hint: Enable service to auto-start, start to run now [OK]

Common Mistakes:

• Using start instead of enable for auto-start
• Confusing reload with enable
• Stopping service instead of enabling

4. You created a systemd service file but after reboot, the program does not start. Which of these is the most likely mistake?

medium

A. You named the service file with a .txt extension

B. You used sudo systemctl start instead of enable

C. You put the program command under the [Unit] section

D. You forgot to run sudo systemctl daemon-reload after creating the service file

Solution

1. Step 1: Understand systemd reload requirement

   After creating or changing service files, systemd must reload to recognize changes.

2. Step 2: Identify the missing reload command

   Forgetting sudo systemctl daemon-reload means systemd ignores new service files.

3. Final Answer:

   You forgot to run sudo systemctl daemon-reload after creating the service file -> Option D

4. Quick Check:

   daemon-reload needed after service file changes [OK]

Hint: Always run daemon-reload after editing service files [OK]

Common Mistakes:

• Skipping daemon-reload after file changes
• Confusing start and enable commands
• Placing ExecStart in wrong section
• Wrong file extension for service files

5. You want your Raspberry Pi to run a Python script at boot, but only after the network is ready. Which systemd service file snippet correctly ensures this?

hard

A. [Unit]\nDescription=Run Python Script\nAfter=network-online.target\nWants=network-online.target\n\n[Service]\nExecStart=/usr/bin/python3 /home/pi/script.py\n\n[Install]\nWantedBy=multi-user.target

B. [Unit]\nDescription=Run Python Script\nRequires=network.target\n\n[Service]\nExecStart=/usr/bin/python3 /home/pi/script.py\n\n[Install]\nWantedBy=multi-user.target

C. [Unit]\nDescription=Run Python Script\nBefore=network-online.target\n\n[Service]\nExecStart=/usr/bin/python3 /home/pi/script.py\n\n[Install]\nWantedBy=multi-user.target

D. [Unit]\nDescription=Run Python Script\nAfter=multi-user.target\n\n[Service]\nExecStart=/usr/bin/python3 /home/pi/script.py\n\n[Install]\nWantedBy=network-online.target

Solution

1. Step 1: Understand network dependency in systemd

   To run after network is ready, use After=network-online.target and Wants=network-online.target.

2. Step 2: Check each option's unit section

   [Unit]\nDescription=Run Python Script\nAfter=network-online.target\nWants=network-online.target\n\n[Service]\nExecStart=/usr/bin/python3 /home/pi/script.py\n\n[Install]\nWantedBy=multi-user.target correctly uses both directives to wait for network online before starting.

3. Final Answer:

   After=network-online.target and Wants=network-online.target -> Option A

4. Quick Check:

   Use After and Wants with network-online.target for network wait [OK]

Hint: Use After=network-online.target and Wants=network-online.target [OK]

Common Mistakes:

• Using network.target instead of network-online.target
• Placing Before=network-online.target instead of After
• Wrong WantedBy target
• Missing Wants directive