Networking in Containers

• Refer Here for networking series in docker
• Docker defined a standard for container networking called as Container Networking Model (CNM)
• CNM is the spec and libnetwork is the implementation

Experiment: Interaction between two containers in default bridge

• Examine default bridge
  
• create a container C1 and C2 in default bridge network

docker container run --name C1 -d alpine sleep 1d
docker container run --name C2 -d alpine sleep 1d

* Now examine default bridge network to find ips of C1 and C2



* Now lets ping C2 from C1 by using ip as well as name

* Two containers in default bridge are able to communicate with each other using ip addresses but not names i.e. name based resolution is not working
* Now create a new bridge network called as learn-net with cidr range 192.168.100.0/24

docker network create -d bridge --subnet "192.168.100.0/24" learn-net

* Now lets create two containers L1 and L2 in the learn-net

docker container run --name L1 --network 'learn-net' -d alpine sleep 1d
docker container run --name L2 --network 'learn-net' -d alpine sleep 1d

• Now ping L2 from L1 using ip and name

docker container exec L1 ping -c4 L2

* In user defined bridge network name based as well ip based communication is enabled

Lets Create nop-commerce application by creating volumes and networks

• Overview
  

steps

• Create a volume nop-db

docker volume create nop-db

• Create a network nopnet

docker network create -d bridge --subnet '10.100.100.0/24' nopnet

• Create a mysql container with username nop, volume, password nop123 in the nopnet with name nopdb

docker container run -d --name nopdb \
    --network nopnet \
    -e "MYSQL_ROOT_PASSWORD=nop123" \
    -e "MYSQL_USER=nop" \
    -e "MYSQL_PASSWORD=nop123" \
    -e "MYSQL_DATABASE=nop" \
    -v nop-db:/var/lib/mysql \
    mysql:8

• Create the nop container on nopnet

docker container run -d --name nop --network nopnet -P nop

* Inspect network

* Now watch the classroom video to bring up the application