Introduce
In MongoDB, “mongod.pid” is a file that stores the process ID (PID) of the MongoDB server process that is currently running. The PID is a unique identifier assigned to a process by the operating system.
When you start the MongoDB server using the “mongod” command, the server creates a “mongod.pid” file in the default data directory (which is usually “/data/db”). This file contains the process ID of the server process that was started.
If you need to stop the MongoDB server, you can use the “mongod --shutdown” command, which will send a shutdown signal to the process ID specified in the “mongod.pid” file.
If the “mongod.pid” file is missing or empty, it means that the MongoDB server is not currently running, or it was started with the “–nojournal” option (which disables the creation of the “mongod.pid” file).
Where
The location of the mongod.pid file can vary depending on the operating system and how MongoDB was installed.
By default, on Linux and macOS systems, the mongod.pid file is located in the /var/run/mongodb/ directory. On Windows, the file is typically located in the \data\db\ directory of your MongoDB installation.
However, if you started MongoDB with a different configuration or command-line option, the location of the mongod.pid file may be different. You can check the contents of your MongoDB configuration file or the command-line options used to start MongoDB to determine the exact location of the mongod.pid file.
In a containerized environment, the location of the mongod.pid file depends on the containerization platform being used and how MongoDB is configured within the container.
If you are using Docker, the mongod.pid file is typically located within the container’s filesystem. You can use the “docker exec” command to execute a shell within the running container and then search for the file within the container’s filesystem. For example:
docker exec -it <container_id> /bin/bash
Once inside the container, you can use the “find” command to search for the mongod.pid file:
find / -name mongod.pid
If you are using a different containerization platform or a custom MongoDB image, the location of the mongod.pid file may be different. You can consult the documentation for your platform or image to determine the exact location of the file.