Docker Network

Default Network Types

Bridged: Default. Connects the docker Virtual Network to the Network of the host
Host: Directly attaches the docker containers to the host network (Faster Performance but less secure)
None: Only localhost interface no access to internet

Third party drivers can be downloaded for creating other types of networks

Bridge Network

When an create a new Container a veth (Virtual Ethernet Network) interface is created between the Container and the Docker Network (docker0) Interface
The bridge Network has its own DHCP and DNS server
All the container connected to the same Virtual Network can communicate with each other without exposing any ports

NOTE

• The default Bridge network does not resolve Container DNS names
• On this network containers can be connected to each other only by using the --link flag (This flag is considered legacy)
• It is recommended to always create a user-defined Bridge Network
• The name of the container is used as its hostname on the network (defaut)

Host Network

On the Host network the Container is directly attached to the Network Interface of the Host System
There is no concept of exposing port ( -p ) as the container is already connected to the Host network

MACVLAN Network

Connect the Docker Container directly to the Switch/ Router of the actual network
Each container will be assigned its own IP Address by the default gateway of the Network and have their own MAC Addresses
They act kind of like Virtual Machines on the Network

docker network create -d macvlan \
	--subnet <network-subnet> \
	--gateway <route-ip> \
	-o parent=<default-interface-name> \
	<network-name>

When we create a Container on this network we need to manually assign it an IP Address using the ( --ip ) flag
This interface does not have its own DHCP server

NOTE

By default we will not be able to ping other devices on the network for that Promiscuous Mode needs to be enabled on the Network Interface

This is the default mode of MACVLAN (Bridge)
It can also be setup in 802.1Q mode

IPVLAN

Supports two modes : L2 (Default) and L3

L2 is similar to MACVLAN but the Containers are not assigned there own MAC Addresses
They share their MAC Addresses with the MAC Address of the Host System
No need to enable Promiscuous Mode
The IP Addresses still need to be assigned manually to the Containers

In L3 mode all the communication happens over Layer 3
We can create Networks to which our Containers will belong and these Networks are connected to the Host device as it the Host device was the router
Containers running in different networks that are created using this approach can also connect with each other
By default the containers cannot access the Internet

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Docker Compose creates a new network automatically for each application (makes working with networks much easier)

docker network ls
docker network inspect <network-name>
 
docker network create <network-name> [-d <driver-name>]
 
docker network connect <network-name> <container-name>
docker network disconnect <network-name> <container-name>

Options
-d: Specify a driver for the network (—driver)
--net-alias: Set an alias for the hostname of a container
--link: Link the containers to each other
--ip: Specify an IP Address