Difference between container port,host port and service port in dcos json in portMappings

docker containers dcos
Kuldeep Dangi picture Kuldeep Dangi · Jan 9, 2018 · Viewed 9k times · Source

I am confused with what all these port signify container port,host port and service port in portMappings, below is my json

"portMappings": [
  {
    "containerPort": 9000,
    "hostPort": 9000,
    "labels": {
      "VIP_0": "/app2n:9000"
    },
    "protocol": "tcp",
    "servicePort": 10101
  }
]

Answer

Mateusz Moneta picture Mateusz Moneta · Jan 9, 2018
  • containerPort is the port in the container, one which your containerized app should listen on,
  • hostPort is the port which will be visible on the Mesos Agent where container is running,
  • servicePort is abstract port for internal use of framework, e.g. it can be used in loadbalancer as port mapped to host on which your run your container and its hostPort. Should be unique across your cluster.

Basically flow looks like this: internet -> <loadbalancer e.g. nginx, haproxy>:<servicePort> -> <mesos agent on which container runs>:<hostPort> -> <container>:<containerPort>

Related questions

How is Docker different from a virtual machine?

I keep rereading the Docker documentation to try to understand the difference between Docker and a full VM. How does it manage to provide a full filesystem, isolated networking environment, etc. without being as heavy? Why is deploying software to …

Read More
How to run a cron job inside a docker container?

I am trying to run a cronjob inside a docker container that invokes a shell script. Yesterday I have been searching all over the web and stack overflow, but I could not really find a solution that works. How can …

Read More
How to get IP address of running docker container

I am using Docker for Mac. I am running a nodejs based microservice in a Docker container. I want to test node microservice through the browser. How to get IP address of running docker container?

Read More