What is the usage of Supervisor in Linux?

Supervisor is a process control system that can be used to monitor and manage background processes. It can start, stop, restart, and manage multiple processes, as well as provide additional features such as process group management, logging, and automatic restart.

This is how Supervisor should be used:

1. Install Supervisor: Use a Linux package manager (such as apt or yum) to install Supervisor.
2. Set up Supervisor: Create a configuration file (usually supervisord.conf) to define the processes to be monitored and their related configuration parameters. The configuration file can include the process starting command, working directory, log file, etc.
3. Start Supervisor: Use the “supervisord” command to launch the Supervisor process and load the configuration file. Once started, Supervisor will initiate the corresponding background processes based on the defined startup commands in the configuration file.
4. Process management: Manage processes using the supervisorctl command. You can use supervisorctl to start, stop, restart, view status, or send signals to processes. For example, use supervisorctl start to start a process.
5. Check the logs: Supervisor will generate a log file for each monitored process, and you can understand the running status of the process by viewing these log files. By default, the log files are stored in Supervisor’s log directory.
6. Automatic restart: Supervisor has the capability to automatically restart processes if they unexpectedly terminate, with the ability to adjust the number of restart attempts and time intervals through configuration settings in the file.

In general, Supervisor offers a convenient way to monitor and manage background processes, ensuring their stable operation.