docs: document homed UID range

This commit is contained in:
Lennart Poettering 2019-08-26 15:31:17 +02:00
parent 28e208a7d8
commit f62dd2375e
1 changed files with 12 additions and 3 deletions

View File

@ -96,7 +96,15 @@ but downstreams are strongly advised against doing that.)
`systemd` defines a number of special UID ranges:
1. 61184…65519 → UIDs for dynamic users are allocated from this range (see the
1. 60001…60513 → UIDs for home directories managed by
[`systemd-homed.service(8)`](https://www.freedesktop.org/software/systemd/man/systemd-homed.service.html). UIDs
from this range are automatically assigned to any home directory discovered,
and persisted locally on first login. On different systems the same user
might get different UIDs assigned in case of conflict, though it is
attempted to make UID assignments stable, by deriving them from a hash of
the user name.
2. 61184…65519 → UIDs for dynamic users are allocated from this range (see the
`DynamicUser=` documentation in
[`systemd.exec(5)`](https://www.freedesktop.org/software/systemd/man/systemd.exec.html)). This
range has been chosen so that it is below the 16bit boundary (i.e. below
@ -111,7 +119,7 @@ but downstreams are strongly advised against doing that.)
user record resolving works correctly without those users being in
`/etc/passwd`.
2. 524288…1879048191 → UID range for `systemd-nspawn`'s automatic allocation of
3. 524288…1879048191 → UID range for `systemd-nspawn`'s automatic allocation of
per-container UID ranges. When the `--private-users=pick` switch is used (or
`-U`) then it will automatically find a so far unused 16bit subrange of this
range and assign it to the container. The range is picked so that the upper
@ -232,7 +240,8 @@ the artifacts the container manager persistently leaves in the system.
| 5 | `tty` group | `systemd` | `/etc/passwd` |
| 6…999 | System users | Distributions | `/etc/passwd` |
| 1000…60000 | Regular users | Distributions | `/etc/passwd` + LDAP/NIS/… |
| 60001…61183 | Unused | | |
| 60001…60513 | Human Users (homed) | `systemd` | `nss-systemd`
| 60514…61183 | Unused | | |
| 61184…65519 | Dynamic service users | `systemd` | `nss-systemd` |
| 65520…65533 | Unused | | |
| 65534 | `nobody` user | Linux | `/etc/passwd` + `nss-systemd` |