SYSTEMD−RANDOM−SEED​.SERVICE - Online Linux Manual PageSection : 8
Updated :
Source : systemd 253
Note : systemd-random-seed.service

NAMEsystemd-random-seed.service, systemd-random-seed − Load and save the OS system random seed at boot and shutdown

SYNOPSISsystemd−random−seed​.service /usr/lib/systemd/random−seed

DESCRIPTIONsystemd−random−seed​.service is a service that loads an on−disk random seed into the kernel entropy pool during boot and saves it at shutdown​. See random(4) for details​. By default, no entropy is credited when the random seed is written into the kernel entropy pool, but this may be changed with $SYSTEMD_RANDOM_SEED_CREDIT, see below​. On disk the random seed is stored in /var/lib/systemd/random−seed​. Note that this service runs relatively late during the early boot phase, i​.e​. generally after the initrd phase has finished and the /var/ file system has been mounted​. Many system services require entropy much earlier than this — this service is hence of limited use for complex system​. It is recommended to use a boot loader that can pass an initial random seed to the kernel to ensure that entropy is available from earliest boot on, for example systemd-boot(7), with its bootctl random−seed functionality​. When loading the random seed from disk, the file is immediately updated with a new seed retrieved from the kernel, in order to ensure no two boots operate with the same random seed​. This new seed is retrieved synchronously from the kernel, which means the service will not complete start−up until the random pool is fully initialized​. On entropy−starved systems this may take a while​. This functionality is intended to be used as synchronization point for ordering services that require an initialized entropy pool to function securely (i​.e​. services that access /dev/urandom without any further precautions)​. Care should be taken when creating OS images that are replicated to multiple systems: if the random seed file is included unmodified each system will initialize its entropy pool with the same data, and thus — if otherwise entropy−starved — generate the same or at least guessable random seed streams​. As a safety precaution crediting entropy is thus disabled by default​. It is recommended to remove the random seed from OS images intended for replication on multiple systems, in which case it is safe to enable entropy crediting, see below​. Also see Safely Building Images[1]​. See Random Seeds[2] for further information​.

ENVIRONMENT$SYSTEMD_RANDOM_SEED_CREDIT By default, systemd−random−seed​.service does not credit any entropy when loading the random seed​. With this option this behaviour may be changed: it either takes a boolean parameter or the special string "force"​. Defaults to false, in which case no entropy is credited​. If true, entropy is credited if the random seed file and system state pass various superficial concisistency checks​. If set to "force" entropy is credited, regardless of these checks, as long as the random seed file exists​.

SEE ALSOsystemd(1), random(4), systemd-boot(7), systemd-stub(7), bootctl(4), systemd-boot-random-seed.service(8)

NOTES 1. Safely Building Images ­https://systemd.io/BUILDING_IMAGES 2. Random Seeds ­https://systemd.io/RANDOM_SEEDS
0
Johanes Gumabo
Data Size   :   9,200 byte
man-systemd-random-seed.8Build   :   2024-12-05, 20:55   :  
Visitor Screen   :   x
Visitor Counter ( page / site )   :   2 / 182,640
Visitor ID   :     :  
Visitor IP   :   18.116.63.107   :  
Visitor Provider   :   AMAZON-02   :  
Provider Position ( lat x lon )   :   39.962500 x -83.006100   :   x
Provider Accuracy Radius ( km )   :   1000   :  
Provider City   :   Columbus   :  
Provider Province   :   Ohio ,   :   ,
Provider Country   :   United States   :  
Provider Continent   :   North America   :  
Visitor Recorder   :   Version   :  
Visitor Recorder   :   Library   :  
Online Linux Manual Page   :   Version   :   Online Linux Manual Page - Fedora.40 - march=x86-64 - mtune=generic - 24.12.05
Online Linux Manual Page   :   Library   :   lib_c - 24.10.03 - march=x86-64 - mtune=generic - Fedora.40
Online Linux Manual Page   :   Library   :   lib_m - 24.10.03 - march=x86-64 - mtune=generic - Fedora.40
Data Base   :   Version   :   Online Linux Manual Page Database - 24.04.13 - march=x86-64 - mtune=generic - fedora-38
Data Base   :   Library   :   lib_c - 23.02.07 - march=x86-64 - mtune=generic - fedora.36

Very long time ago, I have the best tutor, Wenzel Svojanovsky . If someone knows the email address of Wenzel Svojanovsky , please send an email to johanes_gumabo@yahoo.co.id .
If error, please print screen and send to johanes_gumabo@yahoo.co.id
Under development. Support me via PayPal.