I have default nginx file which I am copying on /etc/nginx/sites-available/ location, when I do certain changes in default file the changes are not getting reflected in that file under pod.

I have mentioned the copy command to copy default file under /etc/nginx/sites-available/, wanted to know if this default file is being auto generated by nginx as a result not able to reflect my changes. Is there any way to change default file?

I tried by directly changing the default file inside pod but once pod gets restart changes will be lost.

default file

##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart
# http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a clean
# file but keep this around for reference. Or just disable in sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

# Default server configuration
#
server {
	listen 80 default_server;
	listen [::]:80 default_server;

	# SSL configuration
	#
	# listen 443 ssl default_server;
	# listen [::]:443 ssl default_server;
	#
	# Self signed certs generated by the ssl-cert package
	# Don't use them in a production server!
	#
	# include snippets/snakeoil.conf;

	root /var/www/html;

	# Add index.php to the list if you are using PHP
	index index.html index.htm index.nginx-debian.html;

	server_name _;

	location / {
		# First attempt to serve request as file, then
		# as directory, then fall back to displaying a 404.
		try_files $uri $uri/ =404;
		#Sample testing to the file
	}

	# pass the PHP scripts to FastCGI server listening on 127.0.0.1:8000
	#
	location ~ \.php$ {
		include snippets/fastcgi-php.conf;
	#
		# With php5-cgi alone:
	#	fastcgi_pass 127.0.0.1:9000;
	#	# With php5-fpm:
		fastcgi_pass unix:/var/run/php5-fpm.sock;
	}

	# deny access to .htaccess files, if Apache's document root
	# concurs with nginx's one
	#
	#location ~ /\.ht {
	#	deny all;
	#}
}


# Virtual Host configuration for example.com
#
# You can move that to a different file under sites-available/ and symlink that
# to sites-enabled/ to enable it.
#
#server {
#	listen 80;
#	listen [::]:80;
#
#	server_name example.com;
#
#	root /var/www/example.com;
#	index index.html;
#
#	location / {
#		try_files $uri $uri/ =404;
#	}
#}

Dockerfile

FROM node:12.10.0

ENV APP_ROOT /usr/src/webapp/
ENV DOC_ROOT /var/www/html/

ENV DEV_ENV development
ENV DEV_BASE_HREF https://app.com/app-development/

RUN mkdir -p $APP_ROOT $DOC_ROOT
RUN chmod 777 $DOC_ROOT

COPY . $APP_ROOT

RUN chmod 777 init.sh

RUN apt-get update \
    && apt-get install nginx -y

RUN npm cache clean --force \
    && npm rebuild node-sass \
    && npm install -g @angular/cli@v1.6.5 --unsafe

RUN rm -rf /etc/nginx/sites-available/default

COPY default /etc/nginx/sites-available/default

RUN ls /etc/nginx/sites-available && cat /etc/nginx/sites-available/default



RUN npm cache clear --force && npm install --no-shrinkwrap --update-binary


RUN node --max_old_space_size=8192 ./node_modules/@angular/cli/bin/ng build --prod --env=prod -extract-css false --base-href $DEV_BASE_HREF --output-path=./dist 

EXPOSE 80
ENTRYPOINT ["/bin/bash", "init.sh"]
CMD ["dev"]