nss-systemd

systemd
nss-systemd 8
nss-systemd libnss_systemd.so.2 Provide UNIX user and group name resolution for user/group lookup via Varlink

`libnss_systemd.so.2`

## Description

`nss-systemd` is a plug-in module for the GNU Name Service Switch (NSS) functionality of the GNU C Library (`glibc`), providing UNIX user and group name resolution for services implementing the User/Group Record Lookup API via Varlink, such as the system and service manager systemd 1 (for its `DynamicUser=` feature, see systemd.exec 5 for details) or systemd-homed.service 8.

This module also ensures that the root and nobody users and groups (i.e. the users/groups with the UIDs/GIDs 0 and 65534) remain resolvable at all times, even if they aren't listed in `/etc/passwd` or `/etc/group`, or if these files are missing.

This module preferably utilizes systemd-userdbd.service 8 for resolving users and groups, but also works without the service running.

To activate the NSS module, add `systemd` to the lines starting with `passwd:` and `group:` in `/etc/nsswitch.conf`.

It is recommended to place `systemd` after the `files` or `compat` entry of the `/etc/nsswitch.conf` lines so that `/etc/passwd` and `/etc/group` based mappings take precedence.

## Example

Here is an example `/etc/nsswitch.conf` file that enables `nss-systemd` correctly:

    passwd:         compat mymachines systemd
    group:          compat [SUCCESS=merge] mymachines [SUCCESS=merge] systemd
    shadow:         compat

    hosts:          files mymachines resolve [!UNAVAIL=return] dns myhostname
    networks:       files

    protocols:      db files
    services:       db files
    ethers:         db files
    rpc:            db files

    netgroup:       nis

## See Also

systemd 1, systemd.exec 5, nss-resolve 8, nss-myhostname 8, nss-mymachines 8, nsswitch.conf 5, getent 1