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C#•16mo ago

The Fog from Human Resources

❔ How would i go about making a Load balancer

So im currently learning on how to properly deploy a REST API and i have the following question 1. a domain can only link 1 IP address, so how would i go on about deploying 10 copies of my build to 10 different servers under 1 domain 2. how would i link all of them to run on api.example.com 3. how does the servers decide what server takes on the request

64 Replies

cap5lut•16mo ago

ur assumption that a dns entry can have only one ip address is wrong, it can have multiple there is a lot to load balancing, here are some examples: DNS Round Robin: the dns has multiple ip addresses and the dns resolver picks one in round robin manner GeoDNS: the closest ip based on the client ip will be resolved Anycast Routing: multiple servers share the same ip address, the network automatically routes the request to the closest server using the Border Gateway Protocol Global Load Balancer: a reverse proxy sits behind the domain and routes the traffic to the different servers based on some metrics

The Fog from Human ResourcesOP•16mo ago

thats the one i want cause i want the server to be used that is in use the least at the given time

cap5lut•16mo ago

i dont really have experience with using any in production, but as far as im told nginx is a valid option for that https://docs.nginx.com/nginx/admin-guide/load-balancer/http-load-balancer/

HTTP Load Balancing

Load balance HTTP traffic across web or application server groups, with several algorithms and advanced features like slow-start and session persistence.

The Fog from Human ResourcesOP•16mo ago

thanks

Anchy•16mo ago

second nginx load balancer, its also really easy to setup

IsNotNull•16mo ago

If you want a pure .NET implementation there is also YARP. Its not as mature, and isn't designed to be as full featured as commercial offerings...but its free and really easy to understand if you are already familiar with ASP.NET Core conventions.

The Fog from Human ResourcesOP•16mo ago

Honestly I just want anything that can help me use multiple servers I think I'll go with the nginx option since I'm already familiar with it also while im at it couldnt i just make my own load balancer using ASP.NET? i mean after all its just reverse proxy to different servers

IsNotNull•16mo ago

Yes. Sure. That is exactly what YARP is Its just a library you add to an ASP.NET Core project And comes with conventions for making and configuring your own reverse proxy

The Fog from Human ResourcesOP•16mo ago

this would also allow me to pick the currently least used server cause i rly dont want to overload an already overloaded server its my actual first attempt on making a functional CDN so i hope it works lmao oooh i see yes thats very helpful

IsNotNull•16mo ago

Nginx is mature and respected. You don't need to second guess that choice if you like it. Sounds like you have a couple options

The Fog from Human ResourcesOP•16mo ago

yees

cap5lut•16mo ago

thats indeed good to know, i should play around with yarp as well

The Fog from Human ResourcesOP•16mo ago

its just that my main focus with this, is that i can use the currently least loaded server so i wouldnt need most fancy features that nginx provides (probably) ill def. look into both tho both seem like good options

cap5lut•16mo ago

well, the nginx configuration isnt that hard either:

upstream backend {
    least_conn;
    server backend1.example.com;
    server backend2.example.com;
}

server {
  location / {
    proxy_pass http://backend;
  }
}

upstream backend {
    least_conn;
    server backend1.example.com;
    server backend2.example.com;
}

server {
  location / {
    proxy_pass http://backend;
  }
}

thats it for the least loaded load balancing of the configuration (ofc i skipped the rest of the reverse proxy stuff, etc)

The Fog from Human ResourcesOP•16mo ago

so do i get this right i could have 100 servers, 1 of them is the load balancer running on api.example.com and all the 99 others run on s1.example.com, s2.example.com s3.example.com and so on? and then i just direct api.example.com to one of them?

cap5lut•16mo ago

let me expand the configuration:

The Fog from Human ResourcesOP•16mo ago

aight

cap5lut•16mo ago

worker_processes 1;

events {
  worker_connections 1024;
}

http {
  upstream backend { # all servers to distribute the load
    least_conn; # use the server with the least connections
    server 192.168.0.123;
    server example.com;
    server some.other.server.org;
  }

  server { # this is ur api.example.com load balancer server
    listen 443 ssl http2;
    server_name api.example.com;

    ssl_certificate /etc/ssl/certs/api.example.com.crt;
    ssl_certificate_key /etc/ssl/certs/api.example.com.key;

    ssl_protocols TLSv1.3 TLSv1.2;

    location / {
      proxy_pass http://backend; # could be https as well
      proxy_http_version 1.1;
      proxy_set_header Host $host;
      # set the other proxy headers here
    }
  }
}

worker_processes 1;

events {
  worker_connections 1024;
}

http {
  upstream backend { # all servers to distribute the load
    least_conn; # use the server with the least connections
    server 192.168.0.123;
    server example.com;
    server some.other.server.org;
  }

  server { # this is ur api.example.com load balancer server
    listen 443 ssl http2;
    server_name api.example.com;

    ssl_certificate /etc/ssl/certs/api.example.com.crt;
    ssl_certificate_key /etc/ssl/certs/api.example.com.key;

    ssl_protocols TLSv1.3 TLSv1.2;

    location / {
      proxy_pass http://backend; # could be https as well
      proxy_http_version 1.1;
      proxy_set_header Host $host;
      # set the other proxy headers here
    }
  }
}

The Fog from Human ResourcesOP•16mo ago

(my approach for making my own load balancer wouldve looked smth like this: each server wouldve made some sort of request to api.example.com so api.example.com knows every servers IP at all times, api.example.com can then get some data back for analytics, status and also reverse proxy to it )

cap5lut•16mo ago

that would be a bare minimum for a ssl http2 load balancer thats using the server with the least amount of connections for the new connection

The Fog from Human ResourcesOP•16mo ago

wouldve allowed for a dynamic server thing yknow but idk if thats even a possibility like that

cap5lut•16mo ago

u can edit the config file and let nginx reload it all while being up and running iirc

The Fog from Human ResourcesOP•16mo ago

tell me more abt the proxy_pass attribute, why does it lead to backend only and what is located on backend

The Fog from Human ResourcesOP•16mo ago

is backend a variable

The Fog from Human ResourcesOP•16mo ago

for this

cap5lut•16mo ago

there is also some health check stuff, but i didnt touch that yet exactly

The Fog from Human ResourcesOP•16mo ago

oooh yes i understand now

cap5lut•16mo ago

u couldve also called it unga_bunga or whatever ;p

The Fog from Human ResourcesOP•16mo ago

lmao

cap5lut•16mo ago

backend is basically a server group which also contains the settings for the load balancing (least_conn in this case)

The Fog from Human ResourcesOP•16mo ago

so my current idea for a server structure would be this 1 dedicated database server running on db.example.com 1 dedicated media server running on media.example.com 1 dedicated / shared load balancer for api.example.com and then however many servers i want for the actual processing / REST API is that correct

cap5lut•16mo ago

yeah

The Fog from Human ResourcesOP•16mo ago

yees good thanks a lot

cap5lut•16mo ago

note that if these worker servers arent in some kind of vpn or so u might want to use proxy_pass https//backend; instead, so that the traffic between load balancer and worker is encrypted as well

The Fog from Human ResourcesOP•16mo ago

and nginx will just simply skip servers that are for example unavailable atm right?

cap5lut•16mo ago

yep

The Fog from Human ResourcesOP•16mo ago

id always use https anyways

cap5lut•16mo ago

well if they r on the same machine its not worth the ssl overhead ;p

The Fog from Human ResourcesOP•16mo ago

they probably wont be

cap5lut•16mo ago

yeah, then use https

The Fog from Human ResourcesOP•16mo ago

except yes i would use the load balancer server as a REST API server as well thats why i stated it would be shared it would be a waste to have an entire server just for redírects

cap5lut•16mo ago

maybe also http2 instead of http 1.1, so u get multiplexed streams over the connection

The Fog from Human ResourcesOP•16mo ago

also what exactly does this do

cap5lut•16mo ago

not entirely sure what worker_connections does yet, but worker_processes is the amount of well worker processes nginx spawns for handling the server

The Fog from Human ResourcesOP•16mo ago

also i had this idea i just dunno if its good i wanted to make a GUI program where i can drag my C# project folder into, the program would compile it and send the binary to a list of servers on the server then is a small rest api that will accept the file and set it up properly this way i would never need to connect to each server when new versions come out or smth (i ofc would secure the endpoint somehow)

cap5lut•16mo ago

well i guess u will be using docker or alike to run the services, so just add the worker service container to the server group and u can use its own server as well

The Fog from Human ResourcesOP•16mo ago

honestly i never used docker i used to run all my shit on raw root SCcrying

SCcrying

cap5lut•16mo ago

i would use something like gitlab + ci/cd + docker for that

The Fog from Human ResourcesOP•16mo ago

docker has stuff like autostart and auto restart right?

cap5lut•16mo ago

that and isolation

The Fog from Human ResourcesOP•16mo ago

as long as it prevents me from having to log into each server to drag and drop a server binary

cap5lut•16mo ago

imagine u have 3 microservices running on ur machine and all need different versions of the same lib

The Fog from Human ResourcesOP•16mo ago

i mean i dont rly like relying on third parties so i barely use libraries but yes yes i know what you mean except for Newtonsoft JSON and maybe RestSharp thats a must have. also what do i do about websockets

cap5lut•16mo ago

they arent handled differently afaik

The Fog from Human ResourcesOP•16mo ago

does the proxy pass still apply to them?

cap5lut•16mo ago

yeah, u just need to set the correct headers it seems:

location / {
    proxy_pass http://backend;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $connection_upgrade;
    proxy_set_header Host $host;
}

location / {
    proxy_pass http://backend;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $connection_upgrade;
    proxy_set_header Host $host;
}

The Fog from Human ResourcesOP•16mo ago

I see

cap5lut•16mo ago

i meant more like system packages and alike

The Fog from Human ResourcesOP•16mo ago

Ah Yes yes I'll take a look at docker Any good learning resources recommended?

cap5lut•16mo ago

https://www.docker.com/get-started/

Docker

Get Started | Docker

Get started with Docker Desktop and join millions of developers in faster, more secure app development using containers and beyond.

The Fog from Human ResourcesOP•16mo ago

Bet Imma be back later, I'll leave this post open for some days so I can read back to it

cap5lut•16mo ago

well from what ive said, its really just these 3 links u need: https://docs.nginx.com/nginx/admin-guide/web-server/reverse-proxy/ https://docs.nginx.com/nginx/admin-guide/load-balancer/http-load-balancer/ https://www.docker.com/get-started/

Omnissiah•16mo ago

at work we use haproxy as load balancer

Accord•16mo ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity. Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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