{
    "mode": "man",
    "parameter": "systemd-random-seed",
    "section": "8",
    "url": "https://www.chedong.com/phpMan.php/man/systemd-random-seed/8/json",
    "generated": "2026-06-03T01:44:36Z",
    "synopsis": "systemd-random-seed.service\n/usr/lib/systemd/random-seed",
    "sections": {
        "NAME": {
            "content": "systemd-random-seed.service, systemd-random-seed - Load and save the system random seed at\nboot and shutdown\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "systemd-random-seed.service\n\n/usr/lib/systemd/random-seed\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "systemd-random-seed.service is a service that loads an on-disk random seed into the kernel\nentropy pool during boot and saves it at shutdown. See random(4) for details. By default, no\nentropy is credited when the random seed is written into the kernel entropy pool, but this\nmay be changed with $SYSTEMDRANDOMSEEDCREDIT, see below. On disk the random seed is stored\nin /var/lib/systemd/random-seed.\n\nNote that this service runs relatively late during the early boot phase, i.e. generally after\nthe initial RAM disk (initrd) completed its work, and the /var/ file system has been mounted\nwritable. Many system services require entropy much earlier than this — this service is hence\nof limited use for complex system. It is recommended to use a boot loader that can pass an\ninitial random seed to the kernel to ensure that entropy is available from earliest boot on,\nfor example systemd-boot(7), with its bootctl random-seed functionality.\n\nWhen loading the random seed from disk, the file is immediately updated with a new seed\nretrieved from the kernel, in order to ensure no two boots operate with the same random seed.\nThis new seed is retrieved synchronously from the kernel, which means the service will not\ncomplete start-up until the random pool is fully initialized. On entropy-starved systems this\nmay take a while. This functionality is intended to be used as synchronization point for\nordering services that require an initialized entropy pool to function securely (i.e.\nservices that access /dev/urandom without any further precautions).\n\nCare should be taken when creating OS images that are replicated to multiple systems: if the\nrandom seed file is included unmodified each system will initialize its entropy pool with the\nsame data, and thus — if otherwise entropy-starved — generate the same or at least guessable\nrandom seed streams. As a safety precaution crediting entropy is thus disabled by default. It\nis recommended to remove the random seed from OS images intended for replication on multiple\nsystems, in which case it is safe to enable entropy crediting, see below.\n\nSee Random Seeds[1] for further information.\n",
            "subsections": []
        },
        "ENVIRONMENT": {
            "content": "$SYSTEMDRANDOMSEEDCREDIT\nBy default, systemd-random-seed.service does not credit any entropy when loading the\nrandom seed. With this option this behaviour may be changed: it either takes a boolean\nparameter or the special string \"force\". Defaults to false, in which case no entropy is\ncredited. If true, entropy is credited if the random seed file and system state pass\nvarious superficial concisistency checks. If set to \"force\" entropy is credited,\nregardless of these checks, as long as the random seed file exists.\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "systemd(1), random(4), systemd-boot(7), bootctl(4)\n",
            "subsections": []
        },
        "NOTES": {
            "content": "1. Random Seeds\nhttps://systemd.io/RANDOMSEEDS\n\n\n\nsystemd 249                                                           SYSTEMD-RANDOM-SEED.SERVICE(8)",
            "subsections": []
        }
    },
    "summary": "systemd-random-seed.service, systemd-random-seed - Load and save the system random seed at boot and shutdown",
    "flags": [],
    "examples": [],
    "see_also": [
        {
            "name": "systemd",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/systemd/1/json"
        },
        {
            "name": "random",
            "section": "4",
            "url": "https://www.chedong.com/phpMan.php/man/random/4/json"
        },
        {
            "name": "systemd-boot",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/systemd-boot/7/json"
        },
        {
            "name": "bootctl",
            "section": "4",
            "url": "https://www.chedong.com/phpMan.php/man/bootctl/4/json"
        }
    ]
}