Docker101-Network

// here will going to see how to connect containers

//but wait why don't jus try simple LINKING CONTAINERS? so lets see
// pull the no sql redis database
 docker pull redis
 
 // run a container with the database, check for parameter -d for the daemon way of run the container 
docker run -d --name redis1 redis

//run other container using the redis database
// check for --link flag
//  The value provided to the — link flag is sourcecontainername:containeraliasname.
docker run -it --link redis1:redis --name redisclient1 busybox

// see the entries at /etc/hots  that will allow containers communicat
cat /etc/hosts

//check the conectivity
ping redis

// check how docker injected environment variables with the information of the linked container
SET

//exit the container
exit

//lets create a container with a redis client
docker run -it --link redis1:redis --name client1 redis sh

// now we will going to connect to the redis server running in the other container
redis-cli -h redis

//lets try some redis command
PING
set myvar DOCKER
get myvar

// exit or not, raise other client just for fun
redis-cli -h redis
get myvar

// thanks to https://rominirani.com/docker-tutorial-series-part-8-linking-containers-69a4e5bf50fb#.ji8zkbf88

// *** TRYING something more difficult about dockers networking ?

docker run -itd --name=networktest ubuntu

// the docker network by default is BRIDGE
// list the docker networks availables or created
docker network ls 

//inspect bridge -> thi will show thet containers in the bridge network
docker network inspect bridge

// you could try , to see how to disconnect a container of the net, and inspect again the bridge network
docker network disconnect bridge networktest 

/// creating your own network, -d flag tells to docker to use the bridge driver
docker network create -d bridge my-bridge-network

// inspect your newly created network
docker network inspect my-bridge-network

// create a database postgres container and attached it to our created network, and inspect the network again
docker run -d --net=my-bridge-network --name db training/postgres

// now lets raise a container with a web app in phyton to check the conectivity to the database
docker run -d --name web training/webapp python app.py

//inspect the ip adress of the web app container, keep the ip address
docker inspect web | grep -i address

// enter to the database container
docker exec -it db bash

// try to ping the web app using its ip addredd
ping ip-address

//oops it seems web app is not responding
//inspecting our created network and it seems is not in, lets connect it to the net
docker network connect my-bridge-network web

// inspect again the net or the contair, get the ip address of the web app and try the ping againg
ping ip-address  ### it seems that this time it works

// you are feeling cool? try to connect containers amount different hosts
// hint: you will need to use the overlay driver and maybe an key-value storage 
// a gist? yeah myabe comming soon.

// thanks to https://docs.docker.com/engine/userguide/containers/networkingcontainers/