Create Nginx Loadbalancer

The purpose of the Nginx Loadblancer is to accept all requests and load-balance it across 2 instances of the master application. The scaling of the master service will be defined during the container start-up.

Create nginx.conf

Load balancing with Nginx uses a round-robin algorithm by default if no other method is defined. With round-robin scheme each server is selected in turns according to the order we set them in the nginx.conf file. This balances the number of requests equally between our to two master instances.

***Please notice that the master application will have 2 instances and are refernced by their container-names. The container-name is usually :

• [project-directory]-[image-name-from-docker-compose.yml]-[instance-count]
• Project directory from the start page is : python-nginx-microservice

Now create file nginx.conf and copy the following contents :

events {}
# Define which servers to include in the load balancing scheme.
http {
    upstream app {
        server master;
        server python-nginx-microservice-master-1:3001;
        server python-nginx-microservice-master-2:3001;
     }
# This server accepts all traffic to port 80 and passes it to the upstream.
server {
         listen 80;
         server_name app.com;

         location / {
              proxy_pass http://app;
          }
     }
}

Create Dockerfile.nginx

# using Nginx base image
FROM nginx

# delete nginx default .conf .file
RUN rm /etc/nginx/conf.d/default.conf

# add the .conf file we have created
COPY nginx.conf /etc/nginx/nginx.conf

#start the nginx server
CMD ["/usr/sbin/nginx", "-g", "daemon off;"]

This tells Docker to:

• Build an image starting with the nginx base image
• Remove the old configuration file
• Replace it with the newly updated nginx.conf
• Start the nginx server