Supervisord is a process manager tool that enables you to monitor and control background services and resident processes in a Linux environment. It is designed to help you manage processes that run in the background and require minimal interaction with the user. Supervisord is written in Python and is easy to install and configure.
Overview
Supervisord can be used to manage any process that can be started from the command line. It can be used to start, stop, and restart processes, as well as monitor their status. Supervisord can also be configured to automatically restart processes that have crashed or stopped for any reason.
Installation
Supervisord can be installed on Linux systems using the package manager. For example, on Ubuntu, you can install it using the following command:
sudo apt-get install supervisor
Once installed, you can start and stop Supervisord using the following commands:
sudo service supervisor start
sudo service supervisor stop
Configuration
Supervisord configuration files are written in the INI file format. The configuration file specifies the processes to be managed, their command-line arguments, and other options. The default configuration file is located at /etc/supervisor/supervisord.conf.
Here is an example configuration file that starts a process called myprocess:
[program:myprocess]
command=/path/to/myprocess --arg1 --arg2
autostart=true
autorestart=true
startretries=3
stderr_logfile=/var/log/myprocess.err.log
stdout_logfile=/var/log/myprocess.out.log
In this example, myprocess is started with the command /path/to/myprocess --arg1 --arg2. The autostart and autorestart options are set to true, which means that the process will be started automatically when Supervisord starts, and will be restarted automatically if it crashes or stops for any reason. The startretries option specifies the number of times to attempt to start the process before giving up. The stderr_logfile and stdout_logfile options specify the location of the error and output logs for the process.
Usage
Once Supervisord is running and configured, you can use the supervisorctl command to manage the processes. Here are some examples:
- Start a process:
sudo supervisorctl start myprocess - Stop a process:
sudo supervisorctl stop myprocess - Restart a process:
sudo supervisorctl restart myprocess - Check the status of a process:
sudo supervisorctl status myprocess
You can also use the supervisorctl command to manage all the processes at once. For example, to start all the processes, use the following command:
sudo supervisorctl start all
Options
Here are the available options for the Supervisord command:
| Option | Description |
|---|---|
| -c | Specify an alternate configuration file |
| -d | Run Supervisord as a daemon |
| -e | Print the traceback of errors |
| -h | Print the help message |
| -n | Do not run as a daemon |
| -q | Quiet mode |
| -u | Set the user to run as |
| -v | Verbose mode |
| -V | Print the version number |
Troubleshooting Tips
If you are having issues with Supervisord, here are some troubleshooting tips:
- Check the configuration file for errors. A syntax error in the configuration file can cause Supervisord to fail.
- Check the logs for errors. By default, the logs are located at
/var/log/supervisor/supervisord.log. - Check the status of the processes using the
supervisorctl statuscommand. If a process is in theSTOPPEDstate, it may have crashed or stopped for some other reason.
Notes
- Supervisord is a powerful tool for managing background services and resident processes in Linux environments.
- It is easy to install and configure, and can be used to manage any process that can be started from the command line.
- The
supervisorctlcommand is used to manage the processes, and there are many options available for controlling the behavior of the processes. - If you are having issues with Supervisord, check the configuration file, logs, and process status to troubleshoot the problem.