Docker Networking

Docker Networking
=================

Docker installs three networks by default (automaticallY0).

Bridge              none              host

Bridge is the default network a container gets attached to when run.
  e.g.    docker run unbuntu

    To associate the docker container with any other network
    - associate the container with the other network using the
      network parameter (- - network=xxxxxx )

none:  e.g docker run Ubuntu --network=none

host:  docker run ubuntu --network=host
       (This will associate all containers with port 5000.)

------------------

Bridge network
---------------
 - is an private internal network created by docker on the host
 - all containers attach to the this network by default, and get an internal ip
 address: usually using the 172.17.x.x/16 range.
 - the containers can access each other using this internal ip address if required

 Mapping (external access)- To be able to access these containers from the outside world
 you must map these containers to the docker host as in the other examples.

none:
-----
  - the containers are isolated and not available to any other containers on the
    host.


Host network        docker run ubuntu --network=host
------------
 - Associate the containers to the host network - always port 5000
   - this removes any isolation between the network host and the docker container.
meaning if you were to run a web server on port 5000 it is automatically accessible
on same port externally without requiring any port mapping.

   Therefore you cannot run multiple containers on the same host on the same port
   as the ports are all common to the same ports on the host network.

User Defined Networks
======================
- Can create isolated networks within the docker host.
   - By default docker only creates one internal bridge network.
- You can isolate groups of containers into separate internal networks

CMD:
----
      docker network create \
        --driver bridge \
        --subnet 182.18.0.0./16 \
        custom-isolated-network

Run the docker ls command to list all networks?
-----------------------------------------------

docker network ls

Stdout will list all the networks and shoe=w the names which would include the above

   "customer-isolated-network"


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