Process management with supervisor in Raspberry Pi - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Supervisor status command?

You run supervisorctl status on your Raspberry Pi. What output will you see if the service myapp is running and has been up for 5 minutes?

Raspberry Pi

myapp                          RUNNING   pid 1234, uptime 0:05:00

A myapp RUNNING pid 1234, uptime 0:05:00

B myapp STARTING pid 1234, uptime 0:00:10

C myapp FATAL Exited too quickly

D myapp STOPPED Not running

💡 Hint

Look for the status that means the program is active and running.

The RUNNING status means the process is active. The uptime shows how long it has been running.

🧠 Conceptual

intermediate

Which file does Supervisor use to configure managed programs?

On a Raspberry Pi, where do you usually define the programs Supervisor should manage?

A /usr/bin/supervisord

B /var/log/supervisor.log

C /etc/supervisor/conf.d/*.conf

D /home/pi/.supervisorrc

💡 Hint

Think about configuration files ending with .conf.

Supervisor reads program configurations from files in /etc/supervisor/conf.d/ with .conf extension.

🔧 Debug

advanced

Why does this Supervisor program fail to start?

Given this Supervisor program config snippet, why does the program fail to start? [program:myapp] command=/home/pi/myapp/start.sh user=pi autostart=true autorestart=true The start.sh script is executable and works when run manually.

Raspberry Pi

[program:myapp]
command=/home/pi/myapp/start.sh
user=pi
autostart=true
autorestart=true

A The command path is incorrect; it should be absolute to /usr/bin/start.sh

B The start.sh script requires environment variables not set by Supervisor

C The user 'pi' does not have permission to run Supervisor

D Supervisor cannot run shell scripts directly; it needs a Python script

💡 Hint

Think about environment differences between manual run and Supervisor run.

Supervisor runs programs with a minimal environment. If start.sh depends on environment variables, it may fail.

📝 Syntax

advanced

Which Supervisor config snippet correctly restarts a program on failure?

Choose the correct Supervisor program config to restart myapp automatically if it crashes.

A

[program:myapp]
command=/home/pi/myapp/run.sh
autostart=true
restart_on_failure=true

B

[program:myapp]
command=/home/pi/myapp/run.sh
autostart=false
autorestart=false

C

[program:myapp]
command=/home/pi/myapp/run.sh
restart=always

D

[program:myapp]
command=/home/pi/myapp/run.sh
autostart=true
autorestart=true
startretries=3

💡 Hint

Look for the official Supervisor keys for restarting.

Supervisor uses autostart and autorestart keys to control automatic restarts.

🚀 Application

expert

How to reload Supervisor config without stopping running programs?

You updated a program config file in /etc/supervisor/conf.d/ on your Raspberry Pi. Which command reloads the config and applies changes without stopping running programs?

A supervisorctl reread && supervisorctl update

B supervisorctl restart all

C systemctl restart supervisor

D supervisorctl reload

💡 Hint

One command reads new configs, the other applies them.

The reread command tells Supervisor to scan config files, and update applies changes without stopping unaffected programs.