* systemd-resolved.service and systemd-networkd.service now set
DynamicUser=yes. The users systemd-resolve and systemd-network are
- not created by systemd-sysusers.
+ not created by systemd-sysusers anymore.
+
+ NOTE: This has a chance of breaking nss-ldap and similar NSS modules
+ that embedd a network facing module into any process using getpwuid()
+ or related call: the dynamic allocation of the user ID for
+ systemd-resolved.service means the service manager has to check NSS
+ if the user name is already taken when forking off the service. Since
+ the user in the common case won't be defined in /etc/passwd the
+ lookup is likely to trigger nss-ldap which in turn might use NSS to
+ ask systemd-resolved for hostname lookups. This will hence result in
+ a deadlock: a user name lookup in order to start
+ systemd-resolved.service will result in a host name lookup for which
+ systemd-resolved.service needs to be started already. There are
+ multiple ways to work around this problem: pre-allocate the
+ "systemd-resolve" user on such systems, so that nss-ldap won't be
+ triggered; or use a different NSS package that doesn't do networking
+ in-process but provides a local asynchronous name cache; or configure
+ the NSS package to avoid lookups for UIDs in the range `pkg-config
+ systemd --variable=dynamicuidmin` … `pkg-config systemd
+ --variable=dynamicuidmax`, so that it does not consider itself
+ authoritative for the same UID range systemd allocates dynamic users
+ from.
* The systemd-resolve tool has been renamed to resolvectl (it also
remains available under the old name, for compatibility), and its