Merge pull request #174093 from NixOS/doc-fakenss

nixos/doc: document fakeNss, binSh
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Florian Klink 2022-08-04 21:06:19 +07:00 committed by GitHub
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@ -321,3 +321,32 @@ buildImage {
```
Creating base files like `/etc/passwd` or `/etc/login.defs` is necessary for shadow-utils to manipulate users and groups.
## fakeNss {#ssec-pkgs-dockerTools-fakeNss}
If your primary goal is providing a basic skeleton for user lookups to work,
and/or a lesser privileged user, adding `pkgs.fakeNss` to
the container image root might be the better choice than a custom script
running `useradd` and friends.
It provides a `/etc/passwd` and `/etc/group`, containing `root` and `nobody`
users and groups.
It also provides a `/etc/nsswitch.conf`, configuring NSS host resolution to
first check `/etc/hosts`, before checking DNS, as the default in the absence of
a config file (`dns [!UNAVAIL=return] files`) is quite unexpected.
You can pair it with `binSh`, which provides `bin/sh` as a symlink
to `bashInteractive` (as `/bin/sh` is configured as a shell).
```nix
buildImage {
name = "shadow-basic";
copyToRoot = pkgs.buildEnv {
name = "image-root";
paths = [ binSh pkgs.fakeNss ];
pathsToLink = [ "/bin" "/etc" "/var" ];
};
}
```