https://discuss.hashicorp.com/t/nomad-with-consul-connect-get-502-bad-gateway/47352/1

backend-frontend-wo-connect.nomad

job "ingress_backend_connect" {
  datacenters = ["dc1"]

  group "nginx_ingress" {
    count = 1

    network {
      mode = "host"

      port "http" {
          static = "8080"
      }
    }

    service {
        name = "ingress-http"
        port = "http"
        provider = "nomad"

        check {
            name     = "HTTP Health"
            port = "http"
            path     = "/"
            type     = "http"
            protocol = "http"
            interval = "30s"
            timeout  = "2s"
        }
    }

    task "ingress-container" {
      driver = "docker"

      config {
        network_mode = "host"
        image = "nginx:alpine"
        ports = ["http"]
        volumes = [
          "local/nginx/nginx.conf:/etc/nginx/nginx.conf",
          "local/nginx/default.conf:/etc/nginx/conf.d/default.conf"
        ]
      }


      # nginx.conf
      template {
        data = <<EOH
user  nginx;
worker_processes  auto;
worker_rlimit_nofile  15000;
pid  /var/run/nginx.pid;
include /usr/share/nginx/modules/*.conf;


events {
    worker_connections  2048;
    multi_accept on;
    use epoll;
}


http {
    default_type   application/octet-stream;
    error_log /dev/stdout info;
    server_tokens  off;
    server_names_hash_bucket_size 64;
    include        /etc/nginx/mime.types;
    sendfile       on;
    tcp_nopush     on;
    tcp_nodelay    on;

    charset utf-8;
    source_charset utf-8;
    charset_types text/xml text/plain text/vnd.wap.wml application/javascript application/rss+xml;
    
    include /etc/nginx/conf.d/default.conf;
}
        EOH

        destination = "local/nginx/nginx.conf"
      }


      # default.conf
      template {
        data = <<EOH
server {
    listen 8080;
    listen [::]:8080;

    server_name _;

    location / {
      proxy_pass http://127.0.0.1:7777;
    }
}
        EOH

        destination = "local/nginx/default.conf"
      }

    }
  }

  group "nginx_backend" {
    count = 1

    network {
      mode = "host"
      port "http" {
          static = "7777"
      }
    }

    service {
        name = "backend-http"
        port = "http"
        provider = "nomad"

        check {
            name     = "HTTP Health"
            port = "http"
            path     = "/"
            type     = "http"
            protocol = "http"
            interval = "30s"
            timeout  = "2s"
        }
    }

    task "backend-container" {
      driver = "docker"

      config {
        network_mode = "host"
        image = "nginx:alpine"
        ports = ["http"]
        volumes = [
          "local/nginx/nginx.conf:/etc/nginx/nginx.conf",
          "local/nginx/default.conf:/etc/nginx/conf.d/default.conf",
          "local/nginx/index.html:/usr/share/nginx/html/index.html"
        ]
      }


      # nginx.conf
      template {
        data = <<EOH
user  nginx;
worker_processes  auto;
worker_rlimit_nofile  15000;
pid  /var/run/nginx.pid;
include /usr/share/nginx/modules/*.conf;


events {
    worker_connections  2048;
    multi_accept on;
    use epoll;
}


http {
    default_type   application/octet-stream;
    # access_log   /var/log/nginx/access.log;
    # activate the server access log only when needed
    error_log /dev/stdout info;
    server_tokens  off;
    server_names_hash_bucket_size 64;
    include        /etc/nginx/mime.types;
    sendfile       on;
    tcp_nopush     on;
    tcp_nodelay    on;

    charset utf-8;
    source_charset utf-8;
    charset_types text/xml text/plain text/vnd.wap.wml application/javascript application/rss+xml;
    
    include /etc/nginx/conf.d/default.conf;
}
        EOH

        destination = "local/nginx/nginx.conf"
      }


      # default.conf
      template {
        data = <<EOH
server {
    listen 7777 default_server;
    listen [::]:7777;
    server_name  _;

    access_log /dev/stdout;

    location / {
        root   /usr/share/nginx/html;
        index  index.html index.htm;
    }
    
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }
}
        EOH

        destination = "local/nginx/default.conf"
      }


      # index.html
      template {
        data = <<EOH
<!DOCTYPE html>
<html>
<head>
    <title>Hello Nomad</title>
</head>
<body>
    <h1>No Consul Connect...</h1>
    <p>¯\_(ツ)_/¯</p>
</body>
</html>
        EOH

        destination = "local/nginx/index.html"
      }

    }
  }
}