instruction: Create a comprehensive Dockerfile for networking applications with best practices
output: ```dockerfile
  from the previous section still exists, use
  the following command to update it to publish port 80.
  
  $ docker service update --publish-add 80 my_web
  To verify that it worked, use docker service ls:
  
  $ docker service ls
  
  ID NAME MODE REPLICAS IMAGE PORTS
  4nhxl7oxw5vz my_web replicated 1/1 docker.io/library/nginx@sha256:41ad9967ea448d7c2b203c699b429abe1ed5af331cd92533900c6d77490e0268 *:0->80/tcp
  For more information on how publishing ports works, see
  publish ports.You can update almost every configuration detail about an existing service,
  including the image name and tag it runs. See
  Update a service's image after creation.Remove a serviceTo remove a service, use the docker service remove command. You can remove a
  service by its ID or name, as shown in the output of the docker service ls
  command. The following command removes the my_web service.
  
  $ docker service remove my_web
  Service configuration detailsThe following sections provide details about service configuration. This topic
  does not cover every flag or scenario. In almost every instance where you can
  define a configuration at service creation, you can also update an existing
  service's configuration in a similar way.See the command-line references for
  docker service create and
  docker service update, or run
  one of those commands with the --help flag.Configure the runtime environmentYou can configure the following options for the runtime environment in the
  container:Environment variables using the --env flagThe working directory inside the container using the --workdir flagThe username or UID using the --user flagThe following service's containers have an environment variable $MYVAR
  set to myvalue, run
  ```