sample Nginx configuration on Kubernetes using ConfigMap to configure nginx.

nginx_deployment.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: nginx-conf
data:
  nginx.conf: |
    user nginx;
    worker_processes  3;
    error_log  /var/log/nginx/error.log;
    events {
      worker_connections  10240;
    }
    http {
      log_format  main
              'remote_addr:$remote_addr\t'
              'time_local:$time_local\t'
              'method:$request_method\t'
              'uri:$request_uri\t'
              'host:$host\t'
              'status:$status\t'
              'bytes_sent:$body_bytes_sent\t'
              'referer:$http_referer\t'
              'useragent:$http_user_agent\t'
              'forwardedfor:$http_x_forwarded_for\t'
              'request_time:$request_time';

      access_log	/var/log/nginx/access.log main;

      server {
          listen       80;
          server_name  _;

          location / {
              root   html;
              index  index.html index.htm;
          }
      }
      include /etc/nginx/virtualhost/virtualhost.conf;
    }
  virtualhost.conf: |
    upstream app {
      server localhost:8080;
      keepalive 1024;
    }

    server {
      listen 80 default_server;
      root /usr/local/app;

      access_log /var/log/nginx/app.access_log main;
      error_log /var/log/nginx/app.error_log;

      location / {
        proxy_pass http://app/;
        proxy_http_version 1.1;
      }
    }

---
apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: nginx
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
        volumeMounts:
        - mountPath: /etc/nginx # mount nginx-conf volumn to /etc/nginx
          readOnly: true
          name: nginx-conf
        - mountPath: /var/log/nginx
          name: log
      volumes:
      - name: nginx-conf
        configMap:
          name: nginx-conf # place ConfigMap `nginx-conf` on /etc/nginx
          items:
            - key: nginx.conf
              path: nginx.conf
            - key: virtualhost.conf
              path: virtualhost/virtualhost.conf # dig directory
      - name: log
        emptyDir: {}

---
apiVersion: v1
kind: Service
metadata:
  name: nginx
spec:
  type: LoadBalancer
  ports:
  - port: 80
    targetPort: 80
  selector:
    app: nginx