How to use Docker to build a tomcat cluster using nginx (with pictures and text)

mkdir -p /docker/tomcat/webapp8081

mkdir -p /docker/tomcat/webapp8082

mkdir -p /docker/tomcat/webapp8083 

docker run -d --name tomcat8081 -p 8081:8080 -v /docker/tomcat/webapp8081:/usr/local/tomcat/webapps/ tomcat
docker run -d --name tomcat8082 -p 8082:8080 -v /docker/tomcat/webapp8082:/usr/local/tomcat/webapps/ tomcat
docker run -d --name tomcat8083 -p 8083:8080 -v /docker/tomcat/webapp8083:/usr/local/tomcat/webapps/ tomcat

mkdir -p /docker/nginx/
vim /docker/nginx/nginx.conf
mkdir -p /docker/nginx/html

#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;
#pid logs/nginx.pid;
events {
worker_connections 1024; #Maximum number of connections}
http {
include mime.types;
default_type application/octet-stream;
upstream mytomcat{
server 172.17.0.3:8080 weight=10;
# In addition, the name of mytomcat should be consistent with the name below. It should be consistent with your tomcat IP. server 172.17.0.4:8080 weight=50;
server 172.17.0.5:8080 weight=10;
}
#log_format main '$remote_addr - $remote_user [$time_local] "$request" '
# '$status $body_bytes_sent "$http_referer" '
# '"$http_user_agent" "$http_x_forwarded_for"';
#access_log logs/access.log main;
sendfile on;
#tcp_nopush on;
#keepalive_timeout 0;
keepalive_timeout 65;
#gzip on;
server {
listen 80;
server_name mytomcat;
#charset koi8-r;
#access_log logs/host.access.log main;
location / {
#root html;
# index index.html index.htm;
proxy_connect_timeout 50;
proxy_read_timeout 10;
proxy_send_timeout 20;
proxy_pass http://mytomcat;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
# proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
#root html;
# fastcgi_pass 127.0.0.1:9000;
# fastcgi_index index.php;
# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
#include fastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}
# another virtual host using mix of IP-, name-, and port-based configuration
#
#server {
# listen 8000;
# listen somename:8080;
# server_name somename alias another.alias;
# location / {
#root html;
# index index.html index.htm;
# }
#}
# HTTPS server
#
#server {
# listen 443 ssl;
# server_name localhost;
# ssl_certificate cert.pem;
# ssl_certificate_key cert.key;
# ssl_session_cache shared:SSL:1m;
#ssl_session_timeout 5m;
# ssl_ciphers HIGH:!aNULL:!MD5;
# ssl_prefer_server_ciphers on;
# location / {
#root html;
# index index.html index.htm;
# }
#}
}

docker run -d --name nginx81 -p 81:80 -v /docker/nginx/nginx.conf:/etc/nginx/nginx.conf -v /docker/nginx/html:/usr/share/nginx/html nginx