10 EXAMPLES OF HOW TO GET DOCKER CONTAINER IP ADDRESS
Much of the motivation to show so many different ways is to help folks see the flexibility that I still run into nearly daily which is hard not to excite a hacker. They can also be viewed in this Gist.
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### Example #1 ###
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2e23d01384ac iperf-v1:latest "/usr/bin/iperf -s" 10 minutes ago Up 10 minutes 5001/tcp, 0.0.0.0:32768->5201/tcp compassionate_goodall
# Append the container ID (CID) to the end of an inspect
$ docker inspect --format '{{ .NetworkSettings.IPAddress }}' 2e23d01384ac
172.17.0.1
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### Example #2 ###
# Add -q to automatically parse and return the last CID created.
$ docker inspect --format '{{ .NetworkSettings.IPAddress }}' $(docker ps -q)
172.17.0.1
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### Example #3 ###
# As of Docker v1.3 you can attach to a bash shell
docker exec -it 2e23d01384ac bash
# That drops you into a bash shell then use the 'ip' command to grab the addr
root@2e23d01384ac:/# ip add | grep global
inet 172.17.0.1/16 scope global eth0
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### Example #4 ###
# Same as above but in a single line
$ docker exec -it $(docker ps -q) bash
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### Example #5 ###
# Pop this into your ~/.bashrc (Linux) or ~/.bash_profile (Mac)
dockip() {
docker inspect --format '{{ .NetworkSettings.IPAddress }}' "$@"
}
# Source it to re-read your bashrc/profile
source ~/.bash_profile
# Now run the function with the container ID you want to get the addr of:
$ dockip 2e23d01384ac
172.17.0.1
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### Example #6 ###
# Same as above but no argument needed and always return the latest container IP created.
dockip() {
docker inspect --format '{{ .NetworkSettings.IPAddress }}' $(docker ps -q)
}
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### Example #7 ###
# Add to bashrc/bash_profile to docker exec in passing the CID to dock-exec. E.g dock-exec $(docker ps -q) OR dock-exec 2e23d01384ac
dock-exec() { docker exec -i -t $@ bash ;}
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### Example #8 ###
# Another little bash function you can pop into your bash profile
# Always docker exec into the latest container
dock-exec() { docker exec -i -t $(docker ps -l -q) bash ;}
# The run ip addr
ip a
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### Example #9 ###
# Finally you can export the environmental variables from the running container
docker exec -i -t $(docker ps -l -q) env | grep ADDR
# Output --> CLOUDNETPERF_CARBON_1_PORT_2003_TCP_ADDR=172.17.0.229
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### Example #10 ###
# Or even run the ip address command as a parameter which fires off the ip address command and exits the exec
docker exec -i -t $(docker ps -l -q) ip a
# 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
# link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
# inet 127.0.0.1/8 scope host lo
# valid_lft forever preferred_lft forever
# inet6 ::1/128 scope host
# valid_lft forever preferred_lft forever
# 470: eth0: <BROADCAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default
# link/ether 02:42:ac:11:00:e9 brd ff:ff:ff:ff:ff:ff
# inet 172.17.0.233/16 scope global eth0
# valid_lft forever preferred_lft forever
# inet6 fe80::42:acff:fe11:e9/64 scope link
# valid_lft forever preferred_lft forever
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Bonus Example! 
If you have a user defined network as opposed to the default network, simply grepping on docker inspect is a quick way to parse any field.
Lets say you created a Macvlan network to use the same network as the Docker host eth0 interface. In this case eth0 on the Linux host is the following:
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$ ip a show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 08:00:27:13:e4:52 brd ff:ff:ff:ff:ff:ff
inet 172.16.86.254/24 brd 172.16.86.255 scope global eth0
valid_lft forever preferred_lft forever
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Create a network that will share the eth0 interface:
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$ docker network create -d macvlan \
--subnet=192.168.1.0/24 \
--gateway=192.168.1.1 \
-o parent=eth1 mcv && \
docker run --net=mcv -it --rm alpine /bin/sh
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Now grep details about the container:
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# Get the IP of the most recently started container:
docker inspect $(docker ps -q) | grep IPAddress
# Or get the gateway for the last container started:
docker inspect $(docker ps -q) | grep Gateway
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You can just as easily look at the details of the network:
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# Get the IP of the most recently started container:
docker inspect $(docker ps -q) | grep IPAddress
# Or get the gateway for the last container started:
docker inspect $(docker ps -q) | grep Gateway
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Lastly, take a look at the docker network inspect details to view the metadata of the network mcv1 you created:
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$ docker network inspect mcv1 | grep -i ipv4
"IPv4Address": "192.168.1.106/24",
# or look at the gateway of the network
$ docker network inspect mcv1 | grep Gateway
"Gateway": "192.168.1.1/24"
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