Create your own load balancer24 Sep 2016 - Sreevisakh A
If you have a server running for you apps. It is always better to run a backup server incase something happended to you main server. It always a good Idea to run a minimum of two servers. So that load can be distributed across the servers and incase if one goes down the other will be able to serve the requests. Even deployments can be done in rolling manner without any down time. Here is how I set up my own Load balancer to route traffic to multiple servers. I have started to do this because websockets were not working behind an aws load balancer. But that can be solved by using application load balancer. But if you are not using aws, and want to setup a load balancer. Here is how its done.
This load balancer is basically an nginx server. So our calls will reach this nginx server which will route it to one of the servers which is configured in it. Start with installing nginx.
this will install nginx and a basic configuration.
Depending upon our domain (example.com) with which we access, create the following files,
this is the configuration file for example.com. So when we point example.com to this server using your DNS manager. It will check this file. add the folloeing config to the above file.
this will create a server which listens on port 80. and pass all the request to either servers specified in upstream.
Enabling secure connection (https)
you can also make your load balancer to host ssl cetificates. So that your individual servers need not start https traffic. change the above config to support https as well.
server.cer,server.key are the certificate files for your domain. Getting it form your ssl provider. So now you can point your dns to your load balancer. It will redirect your request any one of the server.
Enabling websocket communication
Aws Classic load balancer doesn't support Web socket communication. If you want to enable web socket connections you have to pass couple of headers to our server. Change our config as follows to support web socket communication.
Enabling the new site
Site configuration files are availble in
/etc/nginx/sites-available, but active sites are available inside
/etc/nginx/sites-enabled so we have to create a symlink inside this folder to activate our site.
After configuration, restart nginx service to make the changes.
If you are working with websockets you may get an error as follows
you can try configuring your load balancer as above. Normal load balancer will not forward
Connection : upgrade header. which will block establishing socket connections.