Supervisor is a powerful tool that allows system administrators to monitor and control a variety of processes on UNIX-like operating systems. While it’s typically installed from system package managers, using pip, Python’s package installer, can be a viable alternative. This approach is beneficial when you need a specific version of Supervisor or your system’s package manager doesn’t offer the latest version. In this blog post, we’ll walk through the process of installing a Supervisor using pip.

What is a Supervisor?

Before diving into the installation process, let’s briefly discuss what a Supervisor is. Supervisor is a client/server system that manages and monitors processes on Linux systems. It starts processes at boot, restarts failed processes and provides a simple interface to manage process functionalities.

Step 1: Install pip

First, ensure that pip is installed on your system. You can install pip via your operating system’s package manager. For Debian/Ubuntu-based systems, use:

sudo apt-get update
sudo apt-get install python3-pip

For RedHat/CentOS, use yum or dnf depending on your distribution version.

Step 2: Install Supervisor

Once pip is installed, install Supervisor by running the following command:

sudo pip install supervisor

This command installs the latest version of Supervisor from the Python Package Index (PyPI).

Step 3: Create a Configuration File

The supervisor requires a configuration file to start. You can create a default configuration file by running:

echo_supervisord_conf > supervisord.conf

Move this file to a more appropriate directory like /etc/supervisor/supervisord.conf. Ensure that you have the necessary permissions to do this.

Step 4: Edit the Configuration File

Customize your supervisord.conf as needed. The file is well-commented, making it easier to understand and configure. Pay particular attention to the [program:x] sections where you define the processes you want the Supervisor to manage.

Step 5: Running Supervisor

To start Supervisor with your configuration file, use:

supervisord -c /etc/supervisor/supervisord.conf

Step 6: Managing Supervisor

Use supervisorctl to manage your processes. For instance, to check the status of your programs, use:

supervisorctl status

Step 7: Automating Supervisor on Startup

If you want Supervisor to start automatically at boot, you need to create a systemd service file or an init script depending on your system’s init system.

For systemd, create a file at /etc/systemd/system/supervisord.service with the following content:

[Unit]
Description=Supervisor daemon

[Service]
Type=forking
ExecStart=/usr/local/bin/supervisord -c /etc/supervisor/supervisord.conf
ExecReload=/usr/local/bin/supervisorctl reload
ExecStop=/usr/local/bin/supervisorctl shutdown
User=root

[Install]
WantedBy=multi-user.target

Enable and start the service using:

sudo systemctl enable supervisord sudo systemctl start supervisord

Conclusion

Installing Supervisor using pip is a straightforward process that offers flexibility in terms of version control and environment customization. Remember, managing Python packages system-wide using pip can sometimes lead to conflicts, so use this method with caution, especially on production systems. With Supervisor installed, you now have a robust tool at your disposal for managing and monitoring your system processes.