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authorLennart Poettering <lennart@poettering.net>2015-07-09 14:46:20 -0300
committerLennart Poettering <lennart@poettering.net>2015-07-09 14:46:20 -0300
commitc01ff965b48bb9693dcd77cbc748b5d8676766b0 (patch)
tree63e50e4f3d4b6e6d3217fa2bf7f700eb19c258de /man
parent43694a8cc70667498f3ffc5d9325b7d0428558e5 (diff)
nss-mymachines: map userns users of containers to real user names
Given a container "foo", that maps user id $UID to container user, using user namespaces, this NSS module extenstion will now map the $UID to a name "vu-foo-$TUID" for the translated UID $UID. Similar, userns groups are mapped to "vg-foo-$TGID" for translated GIDs of $GID. This simple change should make userns users more discoverable. Also, given that many tools like "adduser" check NSS before allocating a UID, should lower the chance of UID range conflicts between tools.
Diffstat (limited to 'man')
-rw-r--r--man/nss-mymachines.xml35
1 files changed, 20 insertions, 15 deletions
diff --git a/man/nss-mymachines.xml b/man/nss-mymachines.xml
index eb1ed2592b..41ec458e4b 100644
--- a/man/nss-mymachines.xml
+++ b/man/nss-mymachines.xml
@@ -59,21 +59,26 @@
<para><command>nss-mymachines</command> is a plugin for the GNU
Name Service Switch (NSS) functionality of the GNU C Library
(<command>glibc</command>) providing hostname resolution for
- containers running locally, that are registered with
+ container names of containers running locally, that are registered
+ with
<citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
- The container names are resolved to IP addresses of the specific
- container, ordered by their scope.</para>
+ The container names are resolved to the IP addresses of the
+ specific container, ordered by their scope.</para>
+
+ <para>The module also resolves user IDs used by containers to user
+ names indicating the container name, and back.</para>
<para>To activate the NSS modules, <literal>mymachines</literal>
- has to be added to the line starting with
- <literal>hosts:</literal> in
+ has to be added to the lines starting with
+ <literal>hosts:</literal>, <literal>passwd:</literal> and
+ <literal>group:</literal> in
<filename>/etc/nsswitch.conf</filename>.</para>
<para>It is recommended to place <literal>mymachines</literal>
- near the end of the <filename>nsswitch.conf</filename> line to
- make sure that this mapping is only used as fallback, and any DNS
- or <filename>/etc/hosts</filename> based mapping takes
- precedence.</para>
+ near the end of the <filename>nsswitch.conf</filename> lines to
+ make sure that its mappings are only used as fallback, and any
+ other mappings, such as DNS or <filename>/etc/hosts</filename>
+ based mappings take precedence.</para>
</refsect1>
<refsect1>
@@ -82,17 +87,17 @@
<para>Here's an example <filename>/etc/nsswitch.conf</filename>
file, that enables <command>mymachines</command> correctly:</para>
-<programlisting>passwd: compat
-group: compat
-shadow: compat
+ <programlisting>passwd: compat <command>mymachines</command>
+group: compat <command>mymachines</command>
+shadow: compat
-hosts: files dns <command>mymachines</command> myhostname
+hosts: files dns <command>mymachines</command> myhostname
networks: files
protocols: db files
services: db files
-ethers: db files
-rpc: db files
+ethers: db files
+rpc: db files
netgroup: nis</programlisting>