we are using ELB to Load balance between two NODEJS server.
Suddenly yesterday the service has started to recieve errors while i have two servers under the ELB.
when removing one of the servers and staying with only one server the service is working fine.
i don't have any log of traffic direction between the the servers and it seems that the system works fine with one server (no matter which one of them) and doesn't work with more than one server.
Any suggestions what should we check ?
10x!
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I have a DO Load Balancer that has 4 servers behind it, I've been using socket.io with Sticky Sessions enabled in the Load Balancer settings and it had been working just fine for a while.
Recently clients have not been able to connect at all getting a 400 error immediately on connection. I haven't changed anything in the way I connect to the sockets at all. If I do require that the transport be 'websocket' only from the client it does connect successfully, but then I lose out on the polling backup (one of the main benefits of socket.io).
Also, connecting directly to one of the droplets works as expected, so the issue definitely stands with the Load Balancer.
Does anyone have any idea as to any kind of set up that should be in place for this to work with the DO Load Balancers? Anything that might have changed recently?
I'm running socket.io on a NodeJS server with Express if that helps at all.
Edit #1: Added a screenshot of the LB Settings
sorry if this is a wrong question on this forum but I am simply just stuck and need some advice. I have a shared hosting service and a cloud based hosting server with node.js installed. I want to host my website as normal but I also want to add real time chat and location tracking using node.js I am confused with what I am reading in several places because node.js is itself a server but not designed to host websites? So I have to run 2 different servers? One for the website and one to run node.js? When I setup the cloud one with a node.js script running I can no longer access the webpages.
Whats the best way for me achieve this as I am just going round in circles. Also is there a way I can set up a server on my PC and run and test both of these together before hand so I see what is needed and get it working as it will stop me ordering servers I dont need.
Many thanks for any help or advice.
Node can serve webpages using a framework like Express, but can cause conflicts if run on the same port as another webserver program (Apache, etc). One solution could be to serve your webpages through your webserver on port 80 (or 443 for HTTPS) and run your node server on a different port in order to send information back and forth.
There are a number of ways you can achieve this but here is one popular approach.
You can use NGINX as your front facing web server and proxy the requests to your backend Node service.
In NGINX, for example, you will configure your upstream service as follows:
upstream lucyservice {
server 127.0.0.1:8000;
keepalive 64;
}
The 8000 you see above is just an example, you may be running your Node service on a different port.
Further in your config (in the server config section) you will proxy the requests to your service as follows:
location / {
proxy_pass http://lucyservice;
}
You're Node service can be running in a process manager like forever / pm2 etc. You can have multiple Node services running in a cluster depending on how many processors your machine has etc.
So to recap - your front facing web server will be handling all traffic on port 80 (HTTP) and or 443 (HTTPS) and this will proxy the requests to your Node service running on whatever port(s) you define. All of this can happen on one single server or multiple if you need / desire.
I recently created an e-commerce site using express and the node server worked fine on my local machine. When I uploaded it to my VPS and tried running it using pm2 and with nodemon, the server stopped responding to requests after few minutes, even when the number of requests is low.
Although all the internal functionalities other than request handling were working well. I used a lot of console.log()s in my codes, is this problem due to the excessive use of console.log()?
I have a Node/Express app on server dedicated to sockets and on the client it's Angular 1.5. Running the code locally on http using the same architecture e.g. separate socket server it all works perfectly fine.
When I run the code locally it creates one connection and does very little polling via xhr. On cloudflare with https it does a lot of polling, reconnects continually and not all the messages seem to be getting to the web client
messages hit cloudflare which then redirects them to a loadbalancer running haproxy which then routes the requests to an app running in a docker instance on another machine.
Your Issue is most likely occuring beacause of an issue with cloudflare only allowing traffic to a limited set of ports. Try one of the ports listed in the below link for your server and try connecting to it.
https://support.cloudflare.com/hc/en-us/articles/200169156-Which-ports-will-Cloudflare-work-with-
After a lot of investigation I found the issue to be down to the config in haproxy. I needed to alter the timeouts around the socket routing.
This was nothing to do with ports not being open on cloudflare.
The following link helped me
http://blog.haproxy.com/2012/11/07/websockets-load-balancing-with-haproxy/
Just after a few weeks of working fine, our Socket.io started spewing errors on some browsers. I've tried updated to the latest Socket.io version, I've tried our setup on different machines, I've tried all sorts of machines, it seems to work on most browsers with no clear pattern of which work.
These errors appear on a second interval:
OPTIONS https://website.com/socket.io/?EIO=2&transport=polling&t=1409760272713-52&sid=Dkp1cq0lpKV75IO8AdA3 socket.io-1.0.6.js:2
XMLHttpRequest cannot load https://website.com/socket.io/?EIO=2&transport=polling&t=1409760272713-52&sid=Dkp1cq0lpKV75IO8AdA3. Invalid HTTP status code 400
We're behind Amazon's ELB, Socket.io on polling because the ELB router doesn't support WebSockets.
I found the problem that has been causing this, and it's is really unexpected...
This problem comes from using load balanced services like AWS ELB (independent EC2 should be fine though) and Heroku, their infrastructure doesn't support Socket.io features fully. AWS ELB flat out won't support WebSockets, and Heroku's router is trash for Socket.io, even in conjunction with socket.io-redis.
The problem is hidden when you use a single server, but as soon you start clustering, you will get issues. A single Heroku dyno on my application worked fine, and then the problems started appearing in production out of development, when we weren't using more than one server. We tried on ELB with sticky-load balance and even then, we still had the same issues.
When socket.io returns 400 errors, in this case it was saying "This session doesn't exist and you never completed the handshake", because you completed the handshake on a different server in your cluster.
The solution for me was just dedicating an EC2 instance for my web app to handle Socket.io.