Get the host name from within the docker container from Python program

Question

As per my application requirement, I need to get the server IP and the server name from the python program. But my application is resides inside the specific docker container on top of the Ubuntu.

I have tried like the below

import os
os.system("hostname")  # to get the hostname
os.system("hostname -i") # to get the host ip

Output: 2496c9ab2f4a172.*.*.*

But it is giving the host name as a it's residing docker containerid and the host_ip as it's private ip address as above. I need the hostname as it is the server name. But when I type these above commands in the terminal I am able to get result what I want.

Anis · Accepted Answer · 2017-04-20 10:32:13Z

5

You won't be able to get the host system's name this way. To get it, you can either define an environment variable, either in your Dockerfile, or when running your container (-e option). Alternatively, you can mount your host /etc/hostname file into the container, or copy it...

This is an example run command I use to set the environment variable HOSTNAME to the host's hostname within the container:

docker run -it -e "HOSTNAME=$(cat /etc/hostname)" <image> <cmd>

In python you can then run os.environ["HOSTNAME"] to get the hostname. As far as the IP address goes, I use this command to get retrieve it from a running container:

route -n | awk '/UG[ \t]/{print $2}'

You will have to install route to be able to use this command. It is included in the package net-tools. apt-get install net-tools

edited Apr 20, 2017 at 10:32

answered Apr 20, 2017 at 7:46

Anis

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2 Comments

Ravi kumar Over a year ago

Thanks for your suggestions. I have tried to add the hostname to the environmental variable to running container. It is not accepting my command. my command is docker run <containername> -e HOST_HOSTNAME = 'hostname' And coming to the IP, i can get it using the ipgetter module like ipgetter.myip()

Ido_f Over a year ago

PyCharm is also being a smart ass and has escaped the $(cat /etc/hostname) part. So in the container, when I type os.environ["HOSTNAME"] I get $(cat /etc/hostname) as a string. Facepalm

Muhammad Saqlain · Accepted Answer · 2018-10-25 07:39:08Z

0

An alternative might be the following:

ENV:

NODENAME: '{{.Node.Hostname}}'

This will get you the Hostname of the Node, where the container is running as an environment variable (tested on Docker-Swarm / CoreOs Stable).

edited Oct 25, 2018 at 7:39

Muhammad Saqlain

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answered Oct 25, 2018 at 7:34

Carsten Bock

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1 Comment

Andrew Over a year ago

This worked great for me. I can get the a3fc2... style name from os.gethostname(), but this gave me the friendly name (e.g. manager-1). Not sure why it was downvoted.

andilabs · Accepted Answer · 2019-03-28 17:01:34Z

0

you can go for something like this:

def determine_docker_host_ip_address():
    cmd = "ip route show"
    import subprocess
    process = subprocess.Popen(cmd.split(), stdout=subprocess.PIPE)
    output, error = process.communicate()
    return str(output).split(' ')[2]

answered Mar 28, 2019 at 17:01

andilabs

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Comments

0x6f6f66 · Accepted Answer · 2022-05-20 15:54:41Z

0

import os

os.uname().nodename

answered May 20, 2022 at 15:54

0x6f6f66

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2 Comments

Anurag A S Over a year ago

Could you please add a bit more description, either why/how the code works or any information about the module

Community Over a year ago

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.

SummerRain · Accepted Answer · 2024-02-05 10:25:14Z

0

You can get the hostname on Linux/Unix systems by using the os package:

import os

os.uname().nodename

However this won't work on systems like Windows, as os.uname is not available there.

Instead, use the platform package, as it works on all systems/platforms:

import platform

platform.node()

edited Feb 5, 2024 at 10:25

answered Feb 5, 2024 at 10:19

SummerRain

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