Container network caveats

5.1 Networking background( for beginners)

5.1.1 Basics: Protocols, interfaces, and ports

5.1.2 Bigger picture: Networks, NAT, and port forwarding

5.2 Docker container networking

docker network ls

5.2.1 Creating a user-defined bridge network

Build a new network with a single command:

docker network create \
--driver bridge \
--label project=dockerinaction \
--label chapter=5    \
--attachable \
--scope local \
--subnet 10.0.42.0/24 \
--ip-range 10.0.42.128/25 \
user-network

5.2.2 Exploring a bridge network

start exploring your new bridge network by creating a new container attached to that network:

docker run -it \
--network user-network \
--name network-explorer \
alpine:3.8 \
sh

docker network create \
--driver bridge \
--label project=dockerinaction \
--label chapter=5 \
--attachable \
--scope local \
--subnet 10.0.43.0/24 \
--ip-range 10.0.43.128/25 \
user-network2

docker network connect \
user-network2 \ 
network-explorer

docker attach network-explorer

5.3 Special container networks: host and null

docker run --rm \
--network host \
alpine:3.8 ip -o addr

docker run --rm \
--network none \
alpine:3.8 ip -o addr

5.4 Handling inbound traffic with NodePort publishing

docker run --rm \
-p 8080 \
alpine:3.8 echo "forward ephemeral TCP -> container TCP 8080"
docker run --rm \
-p 8088:8080/udp \
alpine:3.8 echo "host UDP 8088 -> container UDP 8080"
docker run --rm \
-p 127.0.0.1:8080:8080/tcp \
-p 127.0.0.1:3000:3000/tcp \
alpine:3.8 echo "forward multiple TCP ports from localhost"

5.5 Container networking caveats and customizations

5.5.1 No firewalls or network policies

5.5.2 Custom DNS configuration

docker run --rm \
--hostname barker \ 
alpine:3.8 \
nslookup barker

5.5.3 Externalizing network management