Docker container connection

In front of us to achieve access to the network through the port is operating in the docker container services. Let's connect to a docker container port

Network Port Mapping

We created a python application container.

w3big@w3big:~$ docker run -d -P training/webapp python app.py
fce072cc88cee71b1cdceb57c2821d054a4a59f67da6b416fceb5593f059fc6d

In addition, we can specify the network address binding container, such as binding 127.0.0.1.

We use the -P parameter to create a container, use docker ps port 5000 is bound to see a host port 32768.

w3big@w3big:~$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                     NAMES
fce072cc88ce        training/webapp     "python app.py"     4 minutes ago       Up 4 minutes        0.0.0.0:32768->5000/tcp   grave_hopper

We can also use the -p flag to specify the container port is bound to the host port.

Is the difference between the two ways:

• -P: Is mapped to the inside of the container port random high port on the host.
• -p: inside the container port is bound to the specified host port.

w3big@w3big:~$ docker run -d -p 5000:5000 training/webapp python app.py
33e4523d30aaf0258915c368e66e03b49535de0ef20317d3f639d40222ba6bc0

w3big@w3big:~$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED              STATUS              PORTS                     NAMES
33e4523d30aa        training/webapp     "python app.py"     About a minute ago   Up About a minute   0.0.0.0:5000->5000/tcp    berserk_bartik
fce072cc88ce        training/webapp     "python app.py"     8 minutes ago        Up 8 minutes        0.0.0.0:32768->5000/tcp   grave_hopper

In addition, we can specify the network address binding container, such as binding 127.0.0.1.

w3big@w3big:~$ docker run -d -p 127.0.0.1:5001:5002 training/webapp python app.py
95c6ceef88ca3e71eaf303c2833fd6701d8d1b2572b5613b5a932dfdfe8a857c
w3big@w3big:~$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                                NAMES
95c6ceef88ca        training/webapp     "python app.py"     6 seconds ago       Up 6 seconds        5000/tcp, 127.0.0.1:5001->5002/tcp   adoring_stonebraker
33e4523d30aa        training/webapp     "python app.py"     3 minutes ago       Up 3 minutes        0.0.0.0:5000->5000/tcp               berserk_bartik
fce072cc88ce        training/webapp     "python app.py"     10 minutes ago      Up 10 minutes       0.0.0.0:32768->5000/tcp              grave_hopper

So that we can access the container through the access port 127.0.0.1:5001 5002.

The above example, the default is to bind tcp port, if you want to bind UPD ports, a port in the back plus / udp.

w3big@w3big:~$ docker run -d -p 127.0.0.1:5000:5000/udp training/webapp python app.py
6779686f06f6204579c1d655dd8b2b31e8e809b245a97b2d3a8e35abe9dcd22a
w3big@w3big:~$ docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                                NAMES
6779686f06f6        training/webapp     "python app.py"     4 seconds ago       Up 2 seconds        5000/tcp, 127.0.0.1:5000->5000/udp   drunk_visvesvaraya
95c6ceef88ca        training/webapp     "python app.py"     2 minutes ago       Up 2 minutes        5000/tcp, 127.0.0.1:5001->5002/tcp   adoring_stonebraker
33e4523d30aa        training/webapp     "python app.py"     5 minutes ago       Up 5 minutes        0.0.0.0:5000->5000/tcp               berserk_bartik
fce072cc88ce        training/webapp     "python app.py"     12 minutes ago      Up 12 minutes       0.0.0.0:32768->5000/tcp              grave_hopper

docker port command allows us to quickly and easily view the port binding information.

w3big@w3big:~$ docker port adoring_stonebraker 5002
127.0.0.1:5001

Docker container connection

Port mapping is not the only way to connect to another docker container.

docker has a connection system allows multiple containers together, sharing the connection information.

docker connection will create a parent-child relationship, the parent container in which you can see the information of the sub container.

Naming container

When we create a container of time, docker it will automatically be named. In addition, we can also use the --name to identify the naming container, for example:

w3big@w3big:~$  docker run -d -P --name w3big training/webapp python app.py
43780a6eabaaf14e590b6e849235c75f3012995403f97749775e38436db9a441

We can view the name of the container using a docker ps command.

w3big@w3big:~$ docker ps -l
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                     NAMES
43780a6eabaa        training/webapp     "python app.py"     3 minutes ago       Up 3 minutes        0.0.0.0:32769->5000/tcp   w3big