[bug#72249] [PATCH 0/2] Add xe-guest-utilities and daemon

[bug#72249] [PATCH 0/2] Add xe-guest-utilities and daemon

[Karl Hallsby via Guix-patches via]

This service allows Xen hosts to *nicely* control Guix guests by requesting
graceful shutdowns, restarts, etc. You also get some system information about
the guest displayed by the Xen host.

Karl Hallsby (2):
  gnu: Add xe-guest-utilities.
  services: Add xe-guest-utilities-service-type.

 doc/guix.texi                   |  30 ++++++
 gnu/packages/virtualization.scm |  60 +++++++++++
 gnu/services/virtualization.scm | 179 +++++++++++++++++++++++++++++++-
 3 files changed, 268 insertions(+), 1 deletion(-)


base-commit: ad97f1bdb67015cffe92adba3b94c3b3df576008
--
2.45.2

[bug#72249] [PATCH 1/2] gnu: Add xe-guest-utilities.

[Karl Hallsby via Guix-patches via]

* gnu/packages/virtualization.scm (xe-guest-utilities): Init at 8.4.0

Change-Id: I4daf19dc1964be00554e1c598ef88897081f5d52
---
 gnu/packages/virtualization.scm | 60 +++++++++++++++++++++++++++++++++
 gnu/services/virtualization.scm |  1 +
 2 files changed, 61 insertions(+)

diff --git a/gnu/packages/virtualization.scm b/gnu/packages/virtualization.scm
index 061748bb4a..dc5602e06a 100644
--- a/gnu/packages/virtualization.scm
+++ b/gnu/packages/virtualization.scm
@@ -91,6 +91,7 @@ (define-module (gnu packages virtualization)
   #:use-module (gnu packages gnome)
   #:use-module (gnu packages gnupg)
   #:use-module (gnu packages golang)
+  #:use-module (gnu packages golang-build)
   #:use-module (gnu packages graphviz)
   #:use-module (gnu packages gtk)
   #:use-module (gnu packages haskell)
@@ -2778,6 +2779,65 @@ (define-public xen
     (license license:gpl2)
     (supported-systems '("i686-linux" "x86_64-linux" "armhf-linux"))))
 
+(define-public xe-guest-utilities
+  (package
+    (name "xe-guest-utilities")
+    (version "8.4.0")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url "https://github.com/xenserver/xe-guest-utilities")
+                    (commit (string-append "v" version))))
+              (file-name (git-file-name name version))
+              (sha256
+               (base32
+                "1yqspizhq3ii6cz2w75slaxy8838yyri9pmgc2q1radnm7w735if"))))
+    (build-system go-build-system)
+    (arguments
+     (list
+      #:import-path "github.com/xenserver/xe-guest-utilities"
+      #:install-source? #f
+      #:tests? #f ; There are no tests.
+      #:phases
+      #~(modify-phases %standard-phases
+          ;; Despite using go-build-system, this project does not use Go's build
+          ;; infrastructure to do anything, instead relying on a Makefile.
+          ;; NOTE: This target builds a tarball, but it is only filled with
+          ;; 2 binaries, 1 script, and a bunch of text files; it is tiny.
+          (add-after 'patch-source-shebangs 'fix-udev-rule
+            (lambda* (#:key inputs import-path #:allow-other-keys)
+              (substitute* (string-append "src/" import-path "/mk/xen-vcpu-hotplug.rules")
+                (("/bin/sh") (search-input-file inputs "/bin/sh")))))
+          (replace 'build
+            (lambda* (#:key import-path #:allow-other-keys)
+              (with-directory-excursion (string-append "src/" import-path)
+                ;; Explicitly state version, removes git as native-input.
+                ;; NOTE: The final step of the Makefile's build target is to "cd"
+                ;; to the final build directory.
+                (invoke "make" (string-append "RELEASE=" #$version) "build"))))
+          ;; The default "install" actions produce package-manager-specific
+          ;; outputs, .deb, .rpm, and .tgz. We just copy the final build
+          ;; products out.
+          (replace 'install
+            (lambda* (#:key outputs import-path #:allow-other-keys)
+              (let* ((stage (string-append "src/" import-path "/build/stage"))
+                     (out (assoc-ref outputs "out")))
+                ;; Put udev rules in #$output/lib/udev/rules.d/
+                (copy-recursively (string-append stage "/etc/udev")
+                                  (string-append out "/lib/udev"))
+                ;; Copy produced binaries and scripts
+                (copy-recursively (string-append stage "/usr") out)))))))
+    (native-inputs (list go-golang-org-x-sys))
+    (inputs (list bash-minimal))
+    (home-page "https://github.com/xenserver/xe-guest-utilities")
+    (synopsis "XenServer guest utilities for unix-like operating systems")
+    (description "The XenServer guest utilities enable a Xen-based hypervisor,
+(Citrix XenServer, XCP-NG, etc.) to work with a Xen-enabled Unix-like guest VMs.
+This allows the guest to share information about its state back to the host,
+such IP address, memory usage, etc. and allows the host to inform the guest VM
+about events that change the virtualized hardware, such as hotplugging.")
+    (license license:bsd-2)))
+
 (define-public osinfo-db-tools
   (package
     (name "osinfo-db-tools")
diff --git a/gnu/services/virtualization.scm b/gnu/services/virtualization.scm
index d87e494348..c9f8225570 100644
--- a/gnu/services/virtualization.scm
+++ b/gnu/services/virtualization.scm
@@ -6,6 +6,7 @@
 ;;; Copyright © 2022 Oleg Pykhalov <go.wigust@gmail.com>
 ;;; Copyright © 2022 Leo Nikkilä <hello@lnikki.la>
 ;;; Copyright © 2023 Efraim Flashner <efraim@flashner.co.il>
+;;; Copyright © 2024 Raven Hallsby <karl@hallsby.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
-- 
2.45.2

[bug#72249] [PATCH 2/2] services: Add xe-guest-utilities-service-type.

[Karl Hallsby via Guix-patches via]

* gnu/services/virtualization.scm (xe-guest-utilities-configuration,
  xe-guest-utilities-service-type): New variables.

Change-Id: Ife4e79fa6d1a9d5a21bf7479488884f2a5cf8d56
---
 doc/guix.texi                   |  30 ++++++
 gnu/services/virtualization.scm | 178 +++++++++++++++++++++++++++++++-
 2 files changed, 207 insertions(+), 1 deletion(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 9ba96af459..6a29731b95 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -36873,6 +36873,36 @@ Virtualization Services
 @end table
 @end deftp
 
+@subsubheading Xen Guest Agent
+
+@cindex xen
+@cindex xen guest agent
+
+The Xen guest agent allows a Xen host to control the emulated system.
+The @code{xe-guest-agent} service runs the agent on Guix guests.
+
+@quotation Note
+The default Linux-libre kernel that Guix ships already enables the
+necessary features for a guest.  There is nothing you need to enable for
+the guest to fully support paravirtualization features.
+@end quotation
+
+@defvar xe-guest-agent-service-type
+Service type for the QEMU guest agent service.
+@end defvar
+
+@deftp {Data Type} xe-guest-agent-configuration
+Configuration for the @code{xen-guest-agent} service.
+
+@table @asis
+@item @code{package} (default: @code{xen-guest-utilities})
+The Xen guest utilities package to use.
+
+@item @code{pid-file} (default: @code{"/var/run/xe-daemon.pid"})
+Path to the file holding the PID of xe-deamon.
+@end table
+@end deftp
+
 
 @anchor{build-vm}
 @subsubheading Virtual Build Machines
diff --git a/gnu/services/virtualization.scm b/gnu/services/virtualization.scm
index c9f8225570..29d5de6cc7 100644
--- a/gnu/services/virtualization.scm
+++ b/gnu/services/virtualization.scm
@@ -33,6 +33,9 @@ (define-module (gnu services virtualization)
   #:autoload   (gnu packages gnupg) (guile-gcrypt)
   #:use-module (gnu packages package-management)
   #:use-module (gnu packages ssh)
+  #:use-module (gnu packages base)
+  #:use-module (gnu packages gawk)
+  #:use-module (gnu packages linux)
   #:use-module (gnu packages virtualization)
   #:use-module (gnu services base)
   #:use-module (gnu services configuration)
@@ -107,7 +110,10 @@ (define-module (gnu services virtualization)
 
             qemu-guest-agent-configuration
             qemu-guest-agent-configuration?
-            qemu-guest-agent-service-type))
+            qemu-guest-agent-service-type
+
+            xe-guest-agent-configuration
+            xe-guest-agent-service-type))
 
 (define (uglify-field-name field-name)
   (let ((str (symbol->string field-name)))
@@ -1004,6 +1010,77 @@ (define qemu-guest-agent-service-type
    (default-value (qemu-guest-agent-configuration))
    (description "Run the QEMU guest agent.")))
 
+\f
+;;;
+;;; Guest agent for VMs running under Xen
+;;;
+(define-configuration/no-serialization xe-guest-agent-configuration
+  (package
+   (package xe-guest-utilities)
+   "Xen guest management utilities package.")
+  (pid-file
+   (string "/var/run/xe-daemon.pid")
+   "Path to the file holding the PID of xe-deamon."))
+
+(define (generate-xe-guest-agent-documentation)
+  "Generate documentation for xe-guest-agent fields"
+  (generate-documentation
+   `((xe-guest-agent-configuration ,xe-guest-agent-configuration-fields))
+   'xe-guest-agent-configuration))
+
+(define (xe-guest-agent-shepherd-service config)
+  (let ((xe-guest-utils (xe-guest-agent-configuration-package config))
+        (pid-file (xe-guest-agent-configuration-pid-file config)))
+    (list
+     (shepherd-service
+      (provision '(xe-guest-agent))
+      (requirement '(networking user-processes udev))
+      (documentation "Run the Xen guest management agent.")
+      (start
+       #~(lambda _
+           (let ((pid (make-forkexec-constructor
+                       (list
+                        #$(file-append xe-guest-utils
+                                       "/sbin/xe-daemon")
+                        "-p" #$pid-file)
+                       #:log-file "/var/log/xe-daemon.log"
+                       #:pid-file #$pid-file
+                       #:environment-variables
+                       (list (string-append
+                              "PATH="
+                              #$(file-append xe-guest-utils "/bin") ":"
+                              ;; logger
+                              #$(file-append inetutils "/bin"))))))
+             ;; Run xe-linux-distribution script before starting the actual
+             ;; daemon. The script collects some basic system information that
+             ;; is shared back to the Xen host.
+             (system* #$(file-append xe-guest-utils "/sbin/xe-linux-distribution")
+                      "/var/cache/xe-linux-distribution")
+             ;; Finally, start and return the PID made by
+             ;; make-forkexec-constructor.
+             pid)))
+      (stop #~(make-kill-destructor))))))
+
+(define (xe-guest-agent-udev-rules-service config)
+  (let ((guest-utils (xe-guest-agent-configuration-package config)))
+    (list
+     (file->udev-rule "z10_xen-vcpu-hotplug.rules"
+                      (file-append
+                       guest-utils
+                       ;; I hate this z10_ prefix too
+                       "/lib/udev/rules.d/z10_xen-vcpu-hotplug.rules")))))
+
+(define xe-guest-agent-service-type
+  (service-type
+   (name 'xe-guest-agent)
+   (extensions
+    (list (service-extension shepherd-root-service-type
+                             xe-guest-agent-shepherd-service)
+          (service-extension udev-service-type
+                             xe-guest-agent-udev-rules-service)))
+   (default-value (xe-guest-agent-configuration))
+   (description "Run the Xen guest management utilities.")))
+
 \f
 ;;;
 ;;; Secrets for guest VMs.
@@ -1860,3 +1937,102 @@ (define hurd-vm-service-type
    (description
     "Provide a virtual machine (VM) running GNU/Hurd, also known as a
 @dfn{childhurd}.")))
+
+(define-configuration/no-serialization xe-guest-utilities-configuration
+  (xe-guest-utilities
+   (file-like xe-guest-utilities)
+   "XenServer guest utilities package.")
+  (pid-file
+   (string "/var/run/xe-daemon.pid")
+   "File holding the PID of xe-deamon."))
+
+(define (generate-xe-guest-utilities-documentation)
+  "Generate documentation for xe-guest-utilities fields"
+  (generate-documentation
+   `((xe-guest-utilities-configuration ,xe-guest-utilities-configuration-fields))
+   'xe-guest-utilities-configuration))
+
+(define (xe-guest-utils-service config)
+  (let ((pid-file (xe-guest-utilities-configuration-pid-file config)))
+    (list
+     ;; Generate <shepherd-service>s that run the xe-daemon forever.
+     (shepherd-service
+      (documentation "Run the xe-guest-utilities daemon.")
+      (provision '(xe-guest-utilities-daemon))
+      (requirement '(xe-guest-utilities-procfs
+                     xe-guest-utilities-distro))
+      (start #~(make-forkexec-constructor
+                (list #$(file-append xe-guest-utilities "/bin/xe-daemon")
+                      "-p" #$pid-file)
+                #:pid-file #$pid-file
+                #:environment-variables
+                (list (string-append
+                       "PATH=/run/current-system/profile/bin:"
+                       "/run/current-system/profile/sbin:"
+                       #$(file-append coreutils "/bin") ":"
+                       #$(file-append iproute "/bin")))))
+      (stop #~(make-kill-destructor)))
+
+  ;; Generate one-shot <shepherd-service>s that informs the host hypervisor about
+  ;; the distribution of the guest (Guix in this case)
+  (shepherd-service
+   (documentation "Inform host hypervisor of guest's distribution.")
+   (provision '(xe-guest-utilities-distro))
+   (requirement '(;;xe-guest-utilities-xend
+                  ))
+   (one-shot? #t)
+   (start #~(make-forkexec-constructor
+             (list #$(file-append xe-guest-utilities "/bin/xe-linux-distribution")
+                   "/var/run/xe-linux-distribution")
+             #:environment-variables
+             (list (string-append
+                    "PATH="
+                    #$(file-append xe-guest-utilities "/bin") ":"
+                    #$(file-append coreutils "/bin") ":" ;uname & co
+                    #$(file-append gawk "/bin") ":"
+                    #$(file-append sed "/bin")))))
+   (stop #~(make-kill-destructor)))
+
+  ;; Generate <shepherd-service>s to mount the xen directory in /proc.
+  (shepherd-service
+   (documentation "Mount /proc/xen files.")
+   (provision '(xe-guest-utilities-procfs))
+   (requirement '(file-systems))
+   (start #~(lambda ()
+              (mount "xenfs" "/proc/xen" "/proc/xen")
+              (member "/proc/xen" (mount-points))))
+   (stop #~(lambda ()
+             (umount "/proc/xen" MNT_DETACH)
+             (not (member "/proc/xen" (mount-points))))))
+
+  ;; Generate <shepherd-service>s to create the necessary temporary directories for XenStore.
+  (shepherd-service
+   (documentation "Provide a temporary directory for XenStore.")
+   (provision '(xe-guest-utilities-tmp-dir))
+   (one-shot? #t)
+   (requirement '(file-systems))
+   (start #~(lambda ()
+              (mkdir "/var/run/xenstored")
+              (chmod o755 "/var/run/xenstored")))
+   (stop #~(lambda ()
+             (delete-file-recursively "/var/run/xenstored")))))))
+
+(define (xe-guest-utils-udev-rules-service config)
+  (let ((guest-utils (xe-guest-utilities-configuration-xe-guest-utilities config)))
+    (list
+     (file->udev-rule "z10_xen-vcpu-hotplug.rules"
+                      (file-append
+                       guest-utils
+                       ;; I hate this z10_ prefix too
+                       "/etc/udev/rules.d/z10_xen-vcpu-hotplug.rules")))))
+
+(define xe-guest-utilities-service-type
+  (service-type
+   (name 'xe-guest-utilities)
+   (extensions (list (service-extension shepherd-root-service-type
+                                        xe-guest-utils-service)
+                     (service-extension udev-service-type
+                                        xe-guest-utils-udev-rules-service)))
+   (default-value (xe-guest-utilities-configuration))
+   (description
+    "Enable a Guix System VM to communicate with a Xen-based hypervisor host.")))
-- 
2.45.2

[bug#72249] [PATCH 1/2] gnu: Add xe-guest-utilities.

[Karl Hallsby via Guix-patches via]

* gnu/packages/virtualization.scm (xe-guest-utilities): Init at 8.4.0

Change-Id: I4daf19dc1964be00554e1c598ef88897081f5d52
---
 gnu/packages/virtualization.scm | 88 +++++++++++++++++++++++++++++++++
 gnu/services/virtualization.scm |  1 +
 2 files changed, 89 insertions(+)

diff --git a/gnu/packages/virtualization.scm b/gnu/packages/virtualization.scm
index 9dff421341..3b162474af 100644
--- a/gnu/packages/virtualization.scm
+++ b/gnu/packages/virtualization.scm
@@ -104,6 +104,7 @@ (define-module (gnu packages virtualization)
   #:use-module (gnu packages gnome)
   #:use-module (gnu packages gnupg)
   #:use-module (gnu packages golang)
+  #:use-module (gnu packages golang-build)
   #:use-module (gnu packages gperf)
   #:use-module (gnu packages graphviz)
   #:use-module (gnu packages gtk)
@@ -2772,6 +2773,93 @@ (define-public xen
     (license license:gpl2)
     (supported-systems '("i686-linux" "x86_64-linux" "armhf-linux"))))
 
+(define-public xe-guest-utilities
+  (package
+    (name "xe-guest-utilities")
+    (version "8.4.0")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url "https://github.com/xenserver/xe-guest-utilities")
+                    (commit (string-append "v" version))))
+              (file-name (git-file-name name version))
+              (sha256
+               (base32
+                "1yqspizhq3ii6cz2w75slaxy8838yyri9pmgc2q1radnm7w735if"))))
+    (build-system go-build-system)
+    (arguments
+     (list
+      #:import-path "github.com/xenserver/xe-guest-utilities"
+      #:install-source? #f
+      #:tests? #f ; There are no tests.
+      #:phases
+      #~(modify-phases %standard-phases
+          ;; Despite using go-build-system, this project does not use Go's build
+          ;; infrastructure to do anything, instead relying on a Makefile.
+          ;; NOTE: This target builds a tarball, but it is only filled with
+          ;; 2 binaries, 1 script, and a bunch of text files; it is tiny.
+          (add-after 'patch-source-shebangs 'fix-udev-rule
+            (lambda* (#:key inputs import-path #:allow-other-keys)
+              (substitute* (string-append "src/" import-path "/mk/xen-vcpu-hotplug.rules")
+                (("/bin/sh") (search-input-file inputs "/bin/sh")))))
+          (replace 'build
+            (lambda* (#:key import-path #:allow-other-keys)
+              (let* ((version #$version)
+                     (version-split (string-split version #\.))
+                     (major-version (list-ref version-split 0))
+                     (minor-version (list-ref version-split 1))
+                     (micro-version (list-ref version-split 2))
+                     (build-number  "0"))
+                (with-directory-excursion (string-append "src/" import-path)
+                  ;; Perform a buggy substitution. In Guix, the Go's guestmetric
+                  ;; import will resolve to the source version, NOT the version
+                  ;; the Makefile and sed substituted into build/. So we perform
+                  ;; the correct substitution.
+                  ;; This file list is what make & sed substitute, but we do it
+                  ;; in-place too.
+                  (substitute* (list "xe-daemon/xe-daemon.go"
+                                     "syslog/syslog.go"
+                                     "system/system.go"
+                                     "guestmetric/guestmetric.go"
+                                     "guestmetric/guestmetric_linux.go"
+                                     "xenstoreclient/xenstore.go"
+                                     "xenstore/xenstore.go")
+                    (("@PRODUCT_MAJOR_VERSION@") major-version)
+                    (("@PRODUCT_MINOR_VERSION@") minor-version)
+                    (("@PRODUCT_MICRO_VERSION@") micro-version)
+                    (("@NUMERIC_BUILD_NUMBER@")  build-number))
+                  ;; Explicitly state version, removes git as native-input and
+                  ;; removes using git commit hash as an ID.
+                  ;; NOTE: The final step of the Makefile's build target is to "cd"
+                  ;; to the final build directory.
+                  (invoke "make" "build"
+                          (string-append "RELEASE=" version)
+                          (string-append "PRODUCT_MAJOR_VERSION=" major-version)
+                          (string-append "PRODUCT_MINOR_VERSION=" minor-version)
+                          (string-append "PRODUCT_MICRO_VERSION=" micro-version))))))
+          ;; The default "install" actions produce package-manager-specific
+          ;; outputs, .deb, .rpm, and .tgz. We just copy the final build
+          ;; products out.
+          (replace 'install
+            (lambda* (#:key outputs import-path #:allow-other-keys)
+              (let* ((stage (string-append "src/" import-path "/build/stage"))
+                     (out (assoc-ref outputs "out")))
+                ;; Put udev rules in #$output/lib/udev/rules.d/
+                (copy-recursively (string-append stage "/etc/udev")
+                                  (string-append out "/lib/udev"))
+                ;; Copy produced binaries and scripts
+                (copy-recursively (string-append stage "/usr") out)))))))
+    (native-inputs (list go-golang-org-x-sys))
+    (inputs (list bash-minimal))
+    (home-page "https://github.com/xenserver/xe-guest-utilities")
+    (synopsis "XenServer guest utilities for unix-like operating systems")
+    (description "The XenServer guest utilities enable a Xen-based hypervisor,
+(Citrix XenServer, XCP-ng, etc.) to work with a Xen-enabled Unix-like guest VMs.
+This allows the guest to share information about its state back to the host,
+such IP address, memory usage, etc. and allows the host to inform the guest VM
+about events that change the virtualized hardware, such as hotplugging.")
+    (license license:bsd-2)))
+
 (define-public osinfo-db-tools
   (package
     (name "osinfo-db-tools")
diff --git a/gnu/services/virtualization.scm b/gnu/services/virtualization.scm
index 53f79e367b..c32c47484c 100644
--- a/gnu/services/virtualization.scm
+++ b/gnu/services/virtualization.scm
@@ -6,6 +6,7 @@
 ;;; Copyright © 2022 Oleg Pykhalov <go.wigust@gmail.com>
 ;;; Copyright © 2022 Leo Nikkilä <hello@lnikki.la>
 ;;; Copyright © 2023 Efraim Flashner <efraim@flashner.co.il>
+;;; Copyright © 2024 Raven Hallsby <karl@hallsby.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;

base-commit: 4eaeff997907bc1b67884a6dc087756a50f175e2
-- 
2.46.0

[bug#72249] [PATCH 2/2] services: Add xe-guest-utilities-service-type.

[Karl Hallsby via Guix-patches via]

* gnu/services/virtualization.scm (xe-guest-utilities-configuration,
  xe-guest-utilities-service-type): New variables.
* doc/guix.texi: Document them.

Change-Id: Ife4e79fa6d1a9d5a21bf7479488884f2a5cf8d56
---
 doc/guix.texi                   | 37 +++++++++++++++
 gnu/services/virtualization.scm | 81 ++++++++++++++++++++++++++++++++-
 2 files changed, 117 insertions(+), 1 deletion(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index f7b7569887..ee827717a1 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -37328,6 +37328,43 @@ Virtualization Services
 @end table
 @end deftp
 
+@subsubheading Xen Guest Agent
+
+@cindex xen
+@cindex xen guest agent
+
+The Xen guest agent allows a Xen host to control the emulated system.
+The @code{xe-guest-utilities} service runs the agent on Guix guests.
+
+@quotation Note
+The default Linux-libre kernel that Guix ships already enables the
+necessary paravirtualization features for a guest.  There is nothing you
+need to do for the guest to support Xen's paravirtualization features.
+
+The guest utilities are used to have the guest report information
+@emph{back} to the virtualizing host and support tasks that require
+cooperation between host and guest, like CPU hotplugging.
+@end quotation
+
+@defvar xe-guest-utilities-service-type
+Service type for the Xen guest utilities service.
+@end defvar
+
+@deftp {Data Type} xe-guest-utilities-configuration
+Configuration for the @code{xe-guest-utilities} service.
+
+@table @asis
+@item @code{package} (default: @code{xe-guest-utilities})
+The Xen guest utilities package to use.
+
+@item @code{pid-file} (default: @code{"/var/run/xe-daemon.pid"})
+Path to the file holding the PID of xe-deamon.
+
+@item @code{log-file} (default: @code{"/var/log/xe-guest-utilities.log"})
+Path to @code{xe-guest-utilities} log file.
+@end table
+@end deftp
+
 
 @anchor{build-vm}
 @subsubheading Virtual Build Machines
diff --git a/gnu/services/virtualization.scm b/gnu/services/virtualization.scm
index c32c47484c..874abcd73f 100644
--- a/gnu/services/virtualization.scm
+++ b/gnu/services/virtualization.scm
@@ -33,6 +33,9 @@ (define-module (gnu services virtualization)
   #:autoload   (gnu packages gnupg) (guile-gcrypt)
   #:use-module (gnu packages package-management)
   #:use-module (gnu packages ssh)
+  #:use-module (gnu packages base)
+  #:use-module (gnu packages gawk)
+  #:use-module (gnu packages linux)
   #:use-module (gnu packages virtualization)
   #:use-module (gnu services base)
   #:use-module (gnu services configuration)
@@ -107,7 +110,10 @@ (define-module (gnu services virtualization)
 
             qemu-guest-agent-configuration
             qemu-guest-agent-configuration?
-            qemu-guest-agent-service-type))
+            qemu-guest-agent-service-type
+
+            xe-guest-utilities-configuration
+            xe-guest-utilities-service-type))
 
 (define (uglify-field-name field-name)
   (let ((str (symbol->string field-name)))
@@ -1004,6 +1010,79 @@ (define qemu-guest-agent-service-type
    (default-value (qemu-guest-agent-configuration))
    (description "Run the QEMU guest agent.")))
 
+\f
+;;;
+;;; Guest agent for VMs running under Xen
+;;;
+(define-configuration/no-serialization xe-guest-utilities-configuration
+  (package
+   (package xe-guest-utilities)
+   "Xen guest management utilities package.")
+  (pid-file
+   (string "/var/run/xe-daemon.pid")
+   "Path to the file holding the PID of xe-deamon.")
+  (log-file
+   (string "/var/log/xe-guest-utilties.log")
+   "Path to xe-guest-utilities log file."))
+
+(define (generate-xe-guest-utilities-documentation)
+  "Generate documentation for xe-guest-utilities-configuration fields"
+  (generate-documentation
+   `((xe-guest-utilities-configuration ,xe-guest-utilities-configuration-fields))
+   'xe-guest-utilities-configuration))
+
+(define (xe-guest-utilities-shepherd-service config)
+  (let ((xe-guest-utils (xe-guest-utilities-configuration-package config))
+        (pid-file (xe-guest-utilities-configuration-pid-file config))
+        (log-file (xe-guest-utilities-configuration-log-file config)))
+    (list
+     (shepherd-service
+      (provision '(xen-guest-agent))
+      (requirement '(networking user-processes udev))
+      (documentation "Run the Xen guest management agent.")
+      (start
+       #~(lambda _
+           (let ((pid (make-forkexec-constructor
+                       (list
+                        #$(file-append xe-guest-utils
+                                       "/sbin/xe-daemon")
+                        "-p" #$pid-file)
+                       #:log-file #$log-file
+                       #:pid-file #$pid-file
+                       #:environment-variables
+                       (list (string-append
+                              "PATH="
+                              #$(file-append xe-guest-utils "/bin") ":"
+                              ;; logger
+                              #$(file-append inetutils "/bin"))))))
+             ;; Run xe-linux-distribution script before starting the actual
+             ;; daemon. The script collects some basic system information that
+             ;; is shared back to the Xen host.
+             (system* #$(file-append xe-guest-utils "/sbin/xe-linux-distribution")
+                      "/var/cache/xe-linux-distribution")
+             ;; Finally, start and return the PID made by
+             ;; make-forkexec-constructor.
+             pid)))
+      (stop #~(make-kill-destructor))))))
+
+(define (xe-guest-utilities-udev-rules-service config)
+  (let ((guest-utils (xe-guest-utilities-configuration-package config)))
+    (list
+     (file->udev-rule
+      "z10_xen-vcpu-hotplug.rules"
+      (file-append guest-utils "/lib/udev/rules.d/z10_xen-vcpu-hotplug.rules")))))
+
+(define xe-guest-utilities-service-type
+  (service-type
+   (name 'xe-guest-utilities)
+   (extensions
+    (list (service-extension shepherd-root-service-type
+                             xe-guest-utilities-shepherd-service)
+          (service-extension udev-service-type
+                             xe-guest-utilities-udev-rules-service)))
+   (default-value (xe-guest-utilities-configuration))
+   (description "Run the Xen guest management utilities.")))
+
 \f
 ;;;
 ;;; Secrets for guest VMs.
-- 
2.46.0

[bug#72249] [PATCH 2/2] services: Add xe-guest-utilities-service-type.

[Ludovic Courtès]

Hello,

Karl Hallsby <karl@hallsby.com> skribis:

> * gnu/services/virtualization.scm (xe-guest-utilities-configuration,
>   xe-guest-utilities-service-type): New variables.
> * doc/guix.texi: Document them.
>
> Change-Id: Ife4e79fa6d1a9d5a21bf7479488884f2a5cf8d56

I’m only looking at the doc side of things.  Minor comments:

> +@cindex xen
> +@cindex xen guest agent

“Xen”, capitalized.

> +The Xen guest agent allows a Xen host to control the emulated system.
> +The @code{xe-guest-utilities} service runs the agent on Guix guests.

I’m surprised it’s all “xe-”, not “xen-”, but I guess that’s the way it
is.  :-)

It would be nice to add a sentence or two about what said utilities do,
perhaps with a link to upstream documentation if that helps?

> +@item @code{log-file} (default: @code{"/var/log/xe-guest-utilities.log"})
> +Path to @code{xe-guest-utilities} log file.

“Name of the @code{xe-guest-utilities} log file.”

(We use the term “path” for “search paths”.)

Apart from that LGTM!

Thanks,
Ludo’.