I just installed pm2, I already has done clustering in my app.js using node cluster module.
When I use pm2 start app.js -i 4 to start my app.js it only show me one online instance. It should show me 4 instance Please tell me what is the problem
Screenshot attached
Run this command...
it should work.
pm2 stop all
pm2 delete all
pm2 start app.js -i 2
where i is the number of instance you want to start.
Always use pm2 delete all to unregister the CPU, since if you stop it, it still reserve the CPU
Related
By mistake , I run the following command on the server
pm2start app.js -i 3500
Now on server multiple instances are creating in cluster mode. Can anyone suggest how can i stop this ? And how can i delete already instances ?
Thanks
Pm2 generally gives a name to process group. You can check that with pm2 list and then run
pm2 delete processname
Or run pm2 delete all to delete all processes
in an Ubuntu Server, I am unable to run the node.js app in cluster mode using PM2.
The command I use is :
PM2 start server.js --name Server -i max
When I list the PM2 processes, I can see the Server has Error status.
I have tried looking into the log file generated by PM2 but it's empty.
I am however able to run the same server.js without the cluster mode using :
PM2 start server.js --name Server
doing PM2 Kill and starting all the services again was the solution to above issue.
You could also have used pm2 restart Server to restart it
If you use pm2 kill you will just kill all processes, to clean up afterwards i would recommend to use pm2 flush so all logfiles will be reset
I have gone through this same kind of situations but in my case pm2 is showing error status cause of error in my code.
use the below command
pm2 logs
pm2 logs command helped me by showing some hints to check where exactly the error is occured.
if everything works fine then pm2 list will show you the status online.
you can check the ports running by pm2(not only pm2 but all the process) using below command
sudo netstat -tulpn
I am currently using forever but am considering switching to pm2 because forever does not provide a status option.
I cannot do:
forever status myApp
To determine if my app is running or not I must do:
forever list | grep -i myApp
And even with this it is unreliable because myApp might be listed in a stopped state (I appreciate you could come up with some ugly grep solution to accomodate but I want something natural).
With pm2 the docs say you can do:
pm2 show myApp # Show all informations about application
pm2 seems far more natural.
Any thoughts on how to get app status using forever without grepping the forever list?
How does pm2 compare regarding getting app status?
Forever cannot do this without using forever list.
pm2 can and pm2 show works great with expected exit codes.
I tried pm2 for this sole reason and found it much better than Forever. It does everything Forever does but (unbelievable but true) even simpler than Forever.
The commands are the same with more.
Example:
forever start app.js
pm2 start app.js --name "api" // built in pidfile management here
pm2 start app.js -i 0 --name "api" // load balance your app on all cores! WOW!
pm2 list // same as forever list
pm2 show api // returns 0 or 1 return code as expected
pm2 restart api // if running on multiple cores, restarts all associated processes
Forever is dead, pm2 is the new king! PM2 forever!
No need for reboot crontab entries. pm2 handles that with:
pm2 startup
pm2 save
Done!
I don't have any errors in my node app, but it stops after some requests. Though i have enabled the logs and checked, its showing on different requests.
Is it possible to start the node app whenever it is stopped ?
Currently i am using this to start the node app
To start the app
nohup npm start &
And to find the process id
ps aux | grep node
And to kill certain process
kill -9 PID
I don't want to leave the app stopped. It should be ever running. So, Is it possible to start the app whenever it gets stopped.
Thanks
You can use PM2 to monitor and restart your app for you.
By default if you run your app with PM2 it will auto-restart it if it crashes.
npm install pm2#latest -g
pm2 start index.js
PM2 can also be used to run multiple instances and has commands to stop/restart individual ones.
You can get the process PID using pm2 list as well.
More robust use case:
Start up your app by having PM2 run 'npm start' and also give it a name to refer to it later (it will auto restart if it exits/crashes)
pm2 start npm --name="mySuperApp" -- start
Later you make some changes and want to restart it:
pm2 restart mySuperApp
Eventually you want to stop the app:
pm2 stop mySuperApp
you can use nodemon
installing it with npm install -g nodemon
and running your code like this : nodemon index.js
Finding more documentation here
It will run until your app encounter an error but you can restart it with rs in your console
I have my app running on http://talkwithstranger.com/ and I have deployed it on AWS EC2. I use this command
sudo nohup node index.js &
To continue running my Node JS server even if I close my terminal and exit my SSH.
However, after 2 days everytime I wake up and I find out that the node server itself stops automatically. I checked the running processes by using
ps -ef
and my node script is not there.
Google Chrome say site DNS not found, because NodeJS Express is not running of course to serve my html file, but why it stops itself?
What is causing this unexpected shutdown of my server after every 2 days? I have to manually run nohup again to run it again.
Does nohup has a time to expire or something ?
You should run node.js using a service / process manager. You can use something basic such as forever or supervisord but I would actually advise you to take a look at PM2.
It can do a lot of things - one of them being that it manages your process, makes sure it keeps running, restarts it when it fails, manages the logs, etc. You can also have it autostart when you restart the server.
It becomes really powerful in combination with https://pm2.io, because this enables you to monitor your server's metrics such as CPU and memory remotely and see whether exceptions happened, and much more (such as even remotely updating the software by pulling from git). However, they no longer offer a free plan unfortunately - their plans now start at $79/month, which is a pity. But don't worry, the PM2 application itself is still free and open source, only the monitoring costs money.
Basic usage of PM2:
npm install -g pm2
...to install PM2.
pm2 start my_script.js
Starts a script and lets it run in background.
pm2 status
Shows the status of any running scripts.
pm2 restart all
Restarts all running scripts.
pm2 kill
Stops all scripts and completely shuts down the PM2 daemon.
pm2 monit
Monitors CPU/RAM usage and shows it.
pm2 logs
Shows the last 20 output and error log lines and starts streaming live logs to the console. The logs are stored in the folder ~/.pm2/logs.
Using PM2, your script will not stop - at most, it will restart. And if it does you will be able to more easily understand why because you can easily access logs and watch what happenes with memory usage, etc.
Extra tips:
To avoid filling up the harddisk with logfiles, I recommend installing the module pm2-logrotate:
pm2 install pm2-logrotate
To automatically launch PM2 with the same script on startup when the server starts, you can first save the current configuration:
pm2 save
...and then use the following command to install a startup script - follow the instructions displayed, which will be different based on the exact OS you are using:
pm2 startup
To use PM2 in a more advanced way with multiple processes, custom environment variables, etc., take a look at ecosystem files.
You can try forever.Install using the following command.
npm install -g forever
Then just start forever:
forever start index.js
Another better option for production use is pm2.You can install pm2 with below command
npm install -g pm2
# or
yarn global add pm2
start server
pm2 start index.js
The best thing is you can achieve load balancing with pm2(utilize all available CPU)
pm2 start index.js -i max
For more info, you can visit pm2 documentation page.