Restarting MongoDB automatically if it crashes

Question

I am running MongoDB on an Ubuntu server. It's using an upstart script to start mongod when the machine boots. I noticed that if the process crashes, it doesn't get restarted.

How can I make sure that if it crashes, the mongod process is restarted?

Solution 1

I found the answer myself: the simplest way to achieve that is to add the following two lines at the end of the upstart script installed by MongoDB (/etc/init/mongodb.conf):

respawn
respawn limit 10 90

This will try to restart the process if it terminates, and stop if it crashes more than 10 times in 90 seconds.

Solution 2

Building on the accepted answer (and since I do not have enough rep to comment on it)

Respawn is NOT a mongo configuration parameter, it is for the upstart service configuration file.

respawn
respawn limit 10 90

Digital Ocean has a nice tutorial for using upstart and systemd (newer). https://www.digitalocean.com/community/tutorials/how-to-configure-a-linux-service-to-start-automatically-after-a-crash-or-reboot-part-1-practical-examples

Solution 3

I think you want something like Monit or God here to automatically restart services when they stop/crash. Your description of the crash itself would suggest the OOM Killer, which can be avoided by configuring some swap space on the host.

Comments

[Flavien]

Yes, I know why it crashed, the process ran out of memory. I just had to restart it manually. I'd like the process to restart regardless of why it crashed. A server with no mongod process running is no good to me. On Windows I can configure services to restart automatically if they exit. My question was about what that script should be - I'm sure someone wrote one before.

[fsoppelsa]

Then use Windows.

[deepseadiving]

Do you have a source for this? I can't find this in the docs anywhere. Thanks.

[Flavien]

upstart.ubuntu.com/wiki/Stanzas#respawn