Registry key reference

11 min read

This page is the reference catalog for everything peinit reads from or writes to the registry: the full service-definition schema with types and defaults, and every key peinit touches outside the service definitions. For the meaning of each item, follow the link in its row; this page is for looking up a type, a default, or a path.

Registry value types #

Service definition fields map onto registry value types as follows:

Schema type	Registry type	Is
string	`REG_SZ`	A UTF-8 string.
multi_string	`REG_MULTI_SZ`	An ordered list of strings.
dword	`REG_DWORD`	A 32-bit unsigned integer.
binary	`REG_BINARY`	A raw byte sequence.
(timestamp)	`REG_QWORD`	A 64-bit value — used for timer last-run timestamps.

The service definition schema #

Every service is a key under Machine\System\Services\<name>; these are the values inside it. Only ImagePath is required. Fields are grouped by purpose; for full semantics see Defining a service and the linked pages.

Execution — see The execution environment

Field	Type	Default	Meaning
`ImagePath`	string	(required)	Absolute path to the service binary.
`Arguments`	multi_string	—	Command-line arguments.
`WorkingDirectory`	string	`/`	Working directory (non-empty absolute path).
`TTYPath`	string	—	Absolute path to a terminal to attach as the service's stdio and controlling terminal, e.g. `/dev/console` or `/dev/tty1`. Absent or empty means the daemon default (`/dev/null` stdin, captured output). Attaching a terminal suppresses log capture.
`Environment`	multi_string	—	`KEY=VALUE` pairs added to the environment.
`RuntimeDirectories`	multi_string	—	Directories created directly under `/run` just before the main process starts, each secured for SYSTEM, Administrators, and the service's own SID.
`LimitNOFILE`	dword	—	`RLIMIT_NOFILE`.
`LimitCORE`	dword	—	`RLIMIT_CORE`, in bytes.

Type and readiness — see Simple and Oneshot services

Field	Type	Default	Meaning
`Type`	dword	0 (Simple)	0 = Simple, 1 = Oneshot.
`Readiness`	dword	0 (Notify)	0 = Notify (`READY=1`), 1 = Alive. Ignored for Oneshot.
`RemainAfterExit`	dword	0	Oneshot only — stay Completed after a successful exit.
`SuccessExitCodes`	multi_string	—	Non-zero exit codes treated as success (each 0–255).

Activation — see Triggers and timers

Field	Type	Default	Meaning
`Triggers`	multi_string	—	`boot` and/or `timer:<schedule>`. Absent = demand-only.
`Disabled`	dword	0	If 1, triggers must not activate the service.
`SafeMode`	dword	0	If 1, attempt to start in Safe mode. Critical implies SafeMode.
`Conditions`	multi_string	—	Start-time checks; a failure skips the service.
`Asserts`	multi_string	—	Start-time checks; a failure fails the service.
`PreStartCheckTimeout`	dword	5	Seconds allowed for the helper that evaluates filesystem `Conditions`/`Asserts`; if it overruns, it is killed and the check counts as not satisfied (a Condition skips, an Assert fails).
`TimerPersistent`	dword	1	Catch up a missed timer run after a reboot.
`TimerJitter`	dword	0	Maximum random delay (seconds) added to each firing.

Identity — see Service identity and privileges

Field	Type	Default	Meaning
`Identity`	string	`LocalService`	Principal name or SID for the service token.
`RequiredPrivileges`	multi_string	—	Privilege allow-list; all others are removed from the token.
`HookIdentity`	string	(service's `Identity`)	Identity for `ExecStartPre`/`ExecStartPost`.

Dependencies — see Dependencies and ordering

Field	Type	Default	Meaning
`Requires`	multi_string	—	Hard dependencies.
`Wants`	multi_string	—	Soft dependencies.
`BindsTo`	multi_string	—	Runtime coupling.
`Conflicts`	multi_string	—	Mutual exclusion.
`OnFailure`	string	—	Service to start when this one enters Failed.

Supervision and health — see Keeping services running

Field	Type	Default	Meaning
`ErrorControl`	dword	0 (Normal)	0 = Normal, 1 = Critical (sync + reboot on irrecoverable failure).
`RestartPolicy`	dword	1 (OnFailure)	0 = Never, 1 = OnFailure, 2 = Always.
`RestartMaxRetries`	dword	5	Consecutive restarts before Failed.
`RestartWindow`	dword	120	Seconds of Active health that resets the restart counter.
`RestartDelay`	dword	1	Backoff base (doubles per failure, capped at 60).
`HealthCheck`	string	—	Periodic health-check command.
`HealthCheckInterval`	dword	30	Seconds between health checks.
`HealthCheckTimeout`	dword	5	Seconds before a check is killed and failed.
`HealthCheckRetries`	dword	3	Consecutive failures before unhealthy.
`WatchdogTimeout`	dword	0	Seconds between expected `WATCHDOG=1` pings; 0 disables.

Transition phases — see The service lifecycle and Controlling services

Field	Type	Default	Meaning
`ExecStartPre`	multi_string	—	Commands run before the binary (sequential; any failure aborts start).
`ExecStartPost`	multi_string	—	Commands run after readiness / successful exit (failure logged, not fatal).
`ExecReload`	string	— (SIGHUP)	Reload command, or `signal:<NAME>`.
`StartTimeout`	dword	30	Seconds for the whole start sequence.
`StopTimeout`	dword	10	Seconds between SIGTERM and SIGKILL.

Notify, fds, security, metadata

Field	Type	Default	Meaning
`NotifyAccess`	dword	0 (Main)	Who may send sd_notify (only Main is supported).
`FdStoreMax`	dword	0	Max fds in the fd store; 0 disables it.
`ServiceSecurity`	binary	inherit parent	Descriptor controlling who may manage the service.
`DisplayName`	string	—	Human-readable name for status display.
`Description`	string	—	Description of the service.

Service definition keys #

Key	Type	Purpose	See
`Machine\System\Services\`	(parent key)	Parent of all service definitions; each child key is a service.	Defining a service
`Machine\System\Services\SchemaVersion`	dword	Schema version guard (currently 1).	Defining a service
`Machine\System\Services\<name>\LastTimerRun`	`REG_QWORD`	Last-run timestamp for a single-trigger persistent timer. Written by peinit.	Triggers and timers
`Machine\System\Services\<name>\TimerState\`	(subkey)	Per-trigger last-run timestamps for multi-trigger services. Each value is named by the percent-encoded schedule string and holds a `REG_QWORD`.	Triggers and timers

Boot configuration #

Under Machine\System\Boot\:

Key	Type	Default	Purpose	See
`MaxParallelStarts`	dword (> 0)	10	Maximum services starting concurrently. Missing → default; zero/invalid → Recovery.	Boot and boot modes
`BootSuccessGrace`	dword	30	Seconds a Critical service must hold a satisfying state before boot is successful.	Boot and boot modes
`ShutdownTimeout`	dword	90	Maximum seconds for the whole graceful shutdown.	Shutdown
`SettleTimeout`	dword	5	Seconds to wait for the boot set to settle before starting `boot:settled` services anyway.	Triggers and timers
`PostKillTimeout`	dword	5	Seconds peinit waits for a service cgroup to drain after SIGKILL before treating it as stuck. `ShutdownTimeout` bounds the shutdown as a whole; this bounds one service's last stage of it.	Shutdown

Operational parameters #

Under Machine\System\Init\:

Key	Type	Default	Purpose	See
`ControlSecurity`	binary	SYSTEM full; Administrators shutdown + reload-config	Descriptor for system-level control operations.	Who can manage a service
`MaxControlConnections`	dword	32	Maximum concurrent control-socket connections.	Controlling services
`MaxRequestSize`	dword	65536	Maximum control-socket request size (bytes).	Controlling services
`ConnectionTimeout`	dword	30	Seconds before an idle control connection is closed.	Controlling services
`MaxLogLineLength`	dword	8192	Maximum bytes per service output line before truncation.	Service output and logging
`MaxLogBufferPerService`	dword	65536	Maximum bytes buffered per service pipe before back-pressure.	Service output and logging
`LogReadBytesPerEvent`	dword	16384	Bytes drained from a service's output pipe per readable event. Larger favours throughput on chatty services, smaller favours fairness between them.	Service output and logging
`PreEventdBuffer`	dword	1048576	Total bytes of service output held in memory before eventd is up to receive it. Overflow drops the oldest output; it never blocks a service.	Service output and logging
`EnvVars\`	(parent key)	empty	Default environment variables injected into Phase 2 services (value name = variable, `REG_SZ` data = value). The descriptor here is security-critical.	The execution environment
`ProvisionedPaths\`	(parent key)	empty	Boot-time path provisioning: each child key names one directory or file that peinit creates and secures after registryd starts and before Phase 2 — the registry-backed equivalent of tmpfiles.d.	Boot and boot modes
`ProvisionedPaths\<name>\Kind`	string	(required)	`directory` or `file` — what to create at `Path`.	Boot and boot modes
`ProvisionedPaths\<name>\Path`	string	(required)	Absolute path to create or verify.	Boot and boot modes
`ProvisionedPaths\<name>\Security`	binary	SYSTEM + Administrators full, users read/traverse	Peios file security descriptor to apply to the object.	Boot and boot modes
`ProvisionedPaths\<name>\Required`	dword	0	If 1, a failure to provision this entry sends boot to Recovery mode before Phase 2 starts.	Boot and boot modes

Keys peinit reads from other subsystems #

Key	Type	Purpose	See
`Machine\System\eventd\LogSocketPath`	string	Path of eventd's log datagram socket, where peinit forwards service output.	Service output and logging

Where to start #

For how these fields combine into a working definition and when changes take effect, read Defining a service.

To look up the meaning, valid range, and effect-timing of any key on a live system, use regman.

Edit this page