systemd service for auto-start in Raspberry Pi - Step-by-Step Execution

Concept Flow - systemd service for auto-start

Create service file

↓

Define service details

↓

Enable service

↓

Start service

↓

Service auto-starts on boot

This flow shows how to create, enable, and start a systemd service so it runs automatically when the Raspberry Pi boots.

Execution Sample

Raspberry Pi

[Unit]
Description=My Auto Start Service

[Service]
ExecStart=/usr/bin/python3 /home/pi/myscript.py

[Install]
WantedBy=multi-user.target

This is a simple systemd service file that runs a Python script automatically.

Execution Table

Step	Action	Command/Content	Result
1	Create service file	sudo nano /etc/systemd/system/myservice.service	File opened for editing
2	Write service content	Add [Unit], [Service], [Install] sections	Service file saved
3	Reload systemd	sudo systemctl daemon-reload	systemd reloads new service files
4	Enable service	sudo systemctl enable myservice.service	Service set to start on boot
5	Start service now	sudo systemctl start myservice.service	Service starts running
6	Check status	sudo systemctl status myservice.service	Shows service is active
7	Reboot system	sudo reboot	System restarts and service auto-starts
8	Verify auto-start	sudo systemctl status myservice.service	Service is active after reboot

💡 Process ends after verifying service auto-starts on boot

Variable Tracker

Variable	Start	After Step 2	After Step 4	After Step 5	After Step 8
Service File	Not created	Created with content	Enabled for auto-start	Running	Running after reboot
systemd daemon	Old config	Reloaded with new service	New config active	New config active	New config active
Service Status	Inactive	Inactive	Inactive	Active	Active

Key Moments - 3 Insights

Why do we run 'systemctl daemon-reload' after creating the service file?

Because systemd needs to reload its configuration to recognize the new service file, as shown in step 3 of the execution table.

What does 'enable' do compared to 'start'?

'Enable' sets the service to run automatically on boot (step 4), while 'start' runs the service immediately (step 5). Both are needed for auto-start.

How do we confirm the service runs after reboot?

By checking the service status after reboot (step 8), which shows it is active, confirming auto-start works.

Visual Quiz - 3 Questions

Look at the execution table, what command reloads systemd to recognize the new service?

A sudo systemctl enable myservice.service

B sudo systemctl start myservice.service

C sudo systemctl daemon-reload

D sudo reboot

💡 Hint

Check step 3 in the execution table where systemd reload happens.

At which step is the service set to start automatically on boot?

A Step 4

B Step 5

C Step 2

D Step 7

💡 Hint

Look at the action 'Enable service' in the execution table.

If you skip 'sudo systemctl daemon-reload', what will happen when you try to enable the service?

A Service will enable and start normally

B systemd will not recognize the new service file

C Service will start but not enable on boot

D System will reboot automatically

💡 Hint

Refer to the importance of step 3 in the execution table and variable_tracker for systemd daemon state.

Concept Snapshot

systemd service file syntax:
[Unit] - description
[Service] - command to run
[Install] - target for auto-start
Commands:
daemon-reload (reload configs)
enable (auto-start on boot)
start (run now)
Check status to verify

Full Transcript

To make a program auto-start on Raspberry Pi using systemd, first create a service file in /etc/systemd/system with sections [Unit], [Service], and [Install]. The [Service] section includes the command to run your program. After saving, run 'sudo systemctl daemon-reload' to reload systemd configuration. Then enable the service with 'sudo systemctl enable servicename' to set it to start on boot. Start it immediately with 'sudo systemctl start servicename'. Check status with 'sudo systemctl status servicename'. After reboot, the service will auto-start and can be verified again with status command.

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