services: Add a service for rasdaemon.

* gnu/services/linux.scm (rasdaemon-configuration, rasdaemon-configuration?,
rasdaemon-configuration-record?, rasdaemon-service-type): New variables.
* doc/guix.texi (Linux Services): Document it.

Signed-off-by: Leo Famulari <leo@famulari.name>

doc/guix.texi

@@ -88,6 +88,7 @@ Copyright @copyright{} 2020 John Soo@*
 Copyright @copyright{} 2020 Jonathan Brielmaier@*
 Copyright @copyright{} 2020 Edgar Vincent@*
 Copyright @copyright{} 2021 Maxime Devos@*
+Copyright @copyright{} 2021 B. Wilson@*
 
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU Free Documentation License, Version 1.3 or
@@ -31442,6 +31443,86 @@ parameters, can be done as follow:
 @end lisp
 @end deffn
 
+@cindex rasdaemon
+@cindex Platform Reliability, Availability and Serviceability daemon
+@subsubheading Rasdaemon Service
+
+The Rasdaemon service provides a daemon which monitors the platform Reliablity,
+Availability and Serviceability (RAS) reports from the Linux kernel trace
+events, logging them to syslogd.
+
+Reliability, Availability and Serviceability is a concept used on servers meant
+to measure their robustness.
+
+@strong{Relability} is the probability that a system will produce correct
+outputs:
+
+@itemize @bullet
+@item Generally measured as Mean Time Between Failures (MTBF), and
+@item Enhanced by features that help to avoid, detect and repair hardware
+faults
+@end itemize
+
+@strong{Availability} is the probability that a system is operational at a
+given time:
+
+@itemize @bullet
+@item Generally measured as a percentage of downtime per a period of time, and
+@item Often uses mechanisms to detect and correct hardware faults in runtime.
+@end itemize
+
+@strong{Serviceability} is the simplicity and speed with which a system can be
+repaired or maintained:
+
+@itemize @bullet
+@item Generally measured on Mean Time Between Repair (MTBR).
+@end itemize
+
+
+Among the monitoring measures, the most usual ones include:
+
+@itemize @bullet
+@item CPU – detect errors at instruction execution and at L1/L2/L3 caches;
+@item Memory – add error correction logic (ECC) to detect and correct errors;
+@item I/O – add CRC checksums for transferred data;
+@item Storage – RAID, journal file systems, checksums, Self-Monitoring,
+Analysis and Reporting Technology (SMART).
+@end itemize
+
+By monitoring the number of occurrences of error detections, it is possible to
+identify if the probability of hardware errors is increasing, and, on such
+case, do a preventive maintenance to replace a degraded component while those
+errors are correctable.
+
+For detailed information about the types of error events gathered and how to
+make sense of them, see the kernel administrator's guide at
+@url{https://www.kernel.org/doc/html/latest/admin-guide/ras.html}.
+
+@defvr {Scheme Variable} rasdaemon-service-type
+Service type for the @command{rasdaemon} service.  It accepts a
+@code{rasdaemon-configuration} object.  Instantiating like
+
+@lisp
+(service rasdaemon-service-type)
+@end lisp
+
+will load with a default configuration, which monitors all events and logs to
+syslogd.
+@end defvr
+
+@deftp {Data Type} rasdaemon-configuration
+The data type representing the configuration of @command{rasdaemon}.
+
+@table @asis
+@item @code{record?} (default: @code{#f})
+
+A boolean indicating whether to record the events in an SQLite database.  This
+provides a more structured access to the information contained in the log file.
+The database location is hard-coded to @file{/var/lib/rasdaemon/ras-mc_event.db}.
+
+@end table
+@end deftp
+
 @cindex zram
 @cindex compressed swap
 @cindex Compressed RAM-based block devices

gnu/services/linux.scm

@@ -3,6 +3,7 @@
 ;;; Copyright © 2020 Brice Waegeneire <brice@waegenei.re>
 ;;; Copyright © 2020 Efraim Flashner <efraim@flashner.co.il>
 ;;; Copyright © 2021 raid5atemyhomework <raid5atemyhomework@protonmail.com>
+;;; Copyright © 2021 B. Wilson <elaexuotee@wilsonb.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -47,6 +48,11 @@ (define-module (gnu services linux)
 
             kernel-module-loader-service-type
 
+            rasdaemon-configuration
+            rasdaemon-configuration?
+            rasdaemon-configuration-record?
+            rasdaemon-service-type
+
             zram-device-configuration
             zram-device-configuration?
             zram-device-configuration-size
@@ -188,6 +194,49 @@ (define kernel-module-loader-service-type
    (extend append)
    (default-value '())))
 
+
+;;;
+;;; Reliability, Availability, and Serviceability (RAS) daemon
+;;;
+
+(define-record-type* <rasdaemon-configuration>
+  rasdaemon-configuration make-rasdaemon-configuration
+  rasdaemon-configuration?
+  (record? rasdaemon-configuration-record? (default #f)))
+
+(define (rasdaemon-configuration->command-line-args config)
+  "Translate <rasdaemon-configuration> to its command line arguments
+  representation"
+  (let ((record? (rasdaemon-configuration-record? config)))
+    `(,(file-append rasdaemon "/sbin/rasdaemon")
+      "--foreground" ,@(if record? '("--record") '()))))
+
+(define (rasdaemon-activation config)
+  (let ((record? (rasdaemon-configuration-record? config))
+        (rasdaemon-dir "/var/lib/rasdaemon"))
+    (with-imported-modules '((guix build utils))
+      #~(if #$record? (mkdir-p #$rasdaemon-dir)))))
+
+(define (rasdaemon-shepherd-service config)
+  (shepherd-service
+   (documentation "Run rasdaemon")
+   (provision '(rasdaemon))
+   (requirement '(syslogd))
+   (start #~(make-forkexec-constructor
+             '#$(rasdaemon-configuration->command-line-args config)))
+   (stop #~(make-kill-destructor))))
+
+(define rasdaemon-service-type
+  (service-type
+   (name 'rasdaemon)
+   (default-value (rasdaemon-configuration))
+   (extensions
+    (list (service-extension shepherd-root-service-type
+                             (compose list rasdaemon-shepherd-service))
+          (service-extension activation-service-type rasdaemon-activation)))
+   (compose concatenate)
+   (description "Run @command{rasdaemon}, the RAS monitor")))
+
 
 ;;;
 ;;; Kernel module loader.