---
name: "nss-docker"
section: "8"
platform: "linux"
package: "libnss-docker"
version: "0.02-1.1+b2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/nss-docker"
---

# nss-docker(8)

nss module for finding Docker containers

## NAME

nss-docker - nss module for finding Docker containers

## SYNOPSIS

libnss\_docker.so.2

## DESCRIPTION

This is a plugin for the GNU Name Service Switch (NSS) functionality of the GNU C Library (glibc) providing mechanism for finding Docker containers by theirs IDs.

The container names are searched in virtual domain name `".docker"`.

The Docker API webservice has to be available as */var/run/docker.sock* socket for current user. Usually it requires to add the user to `"docker"` system group.

To activate this NSS module, the `"docker"` module has to be added to */etc/nsswitch.conf* file in `"hosts:"` line.

It is recommended to put the `"docker"` module after `"files"` module and before `"dns"` module. `"[NOTFOUND=return]"` setting is recommended before `"dns"` module to prevent using DNS as fallback if the container ID is not found.

## EXAMPLE

### */etc/nsswitch.conf*

hosts: files docker \[NOTFOUND=return\] dns

## SEE ALSO

[*docker*(1)](/docker/1.md), [*nsswitch.conf*(5)](/nsswitch.conf/5.md)

## LIMITATIONS

The container ID can't be longer than `"getconf HOST_NAME_MAX"` (64 for Linux).

The container ID are case sensitive. It means that `"test.docker"` and `"Test.docker"` can return different IP addresses.

Only IPv4 addresses are supported.

## BUGS

If you find the bug or want to implement new features, please report it at \<https://github.com/dex4er/nss-docker/issues\>

## AUTHORS

Copyright (c) 2015 Piotr Roszatycki \<dexter@debian.org\>

## COPYING

nss-docker is distributed under the GNU Lesser General Public License (LGPL 2.1 or greater).