From 953c65ffdd43c02c934518fb7a1c68542584b223 Mon Sep 17 00:00:00 2001 From: Ludovic Courtès Date: Thu, 21 Sep 2023 16:38:22 +0200 Subject: services: hurd-vm: Implement zero-configuration offloading. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This allows for zero-configuration offloading to a childhurd. * gnu/services/virtualization.scm (operating-system-with-offloading-account): New procedure. ()[offloading?]: New field. (hurd-vm-disk-image): Define ‘transform’ and use it. (hurd-vm-activation): Generate SSH key for user ‘offloading’ and add authorize it via /etc/childhurd/etc/ssh/authorized_keys.d. (hurd-vm-configuration-offloading-ssh-key) (hurd-vm-guix-extension): New procedures. (hurd-vm-service-type): Add GUIX-SERVICE-TYPE extension. * gnu/tests/virtualization.scm (run-childhurd-test)[import-module?]: New procedure. [os]: Add (gnu build install) and its closure to #:import-modules. [test]: Add “copy-on-write store” and “offloading” tests. * doc/guix.texi (Virtualization Services): Document it. --- doc/guix.texi | 71 +++++++++++++++++++------------ gnu/services/virtualization.scm | 92 +++++++++++++++++++++++++++++++++++++++-- gnu/tests/virtualization.scm | 38 ++++++++++++++++- 3 files changed, 169 insertions(+), 32 deletions(-) diff --git a/doc/guix.texi b/doc/guix.texi index e03840aa16..8c5697589f 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -35722,6 +35722,15 @@ guix shell tigervnc-client -- vncviewer localhost:5900 The default configuration (see @code{hurd-vm-configuration} below) spawns a secure shell (SSH) server in your GNU/Hurd system, which QEMU (the virtual machine emulator) redirects to port 10222 on the host. +By default, the service enables @dfn{offloading} such that the host +@code{guix-daemon} automatically offloads GNU/Hurd builds to the +childhurd (@pxref{Daemon Offload Setup}). This is what happens when +running a command like the following one, where @code{i586-gnu} is the +system type of 32-bit GNU/Hurd: + +@example +guix build emacs-minimal -s i586-gnu +@end example The childhurd is volatile and stateless: it starts with a fresh root file system every time you restart it. By default though, all the files @@ -35855,6 +35864,41 @@ with forwarded ports: @var{vnc-port}: @code{(+ 15900 (* 1000 @var{ID}))} @end example +@cindex childhurd, offloading +@cindex Hurd, offloading +@item @code{offloading?} (default: @code{#t}) +Whether to automatically set up offloading of builds to the childhurd. + +When enabled, this lets you run GNU/Hurd builds on the host and have +them transparently offloaded to the VM, for instance when running a +command like this: + +@example +guix build coreutils -s i586-gnu +@end example + +This option automatically sets up offloading like so: + +@enumerate +@item +Authorizing the childhurd's key on the host so that the host accepts +build results coming from the childhurd, which can be done like so +(@pxref{Invoking guix archive, @command{guix archive --authorize}}, for +more on that). + +@item +Creating a user account called @code{offloading} dedicated to offloading +in the childhurd. + +@item +Creating an SSH key pair on the host and making it an authorized key of +the @code{offloading} account in the childhurd. + +@item +Adding the childhurd to @file{/etc/guix/machines.scm} (@pxref{Daemon +Offload Setup}). +@end enumerate + @item @code{secret-root} (default: @file{/etc/childhurd}) The root directory with out-of-band secrets to be installed into the childhurd once it runs. Childhurds are volatile which means that on @@ -35872,38 +35916,13 @@ with the following non-volatile secrets, unless they already exist: /etc/childhurd/etc/guix/acl /etc/childhurd/etc/guix/signing-key.pub /etc/childhurd/etc/guix/signing-key.sec +/etc/childhurd/etc/ssh/authorized_keys.d/offloading /etc/childhurd/etc/ssh/ssh_host_ed25519_key /etc/childhurd/etc/ssh/ssh_host_ecdsa_key /etc/childhurd/etc/ssh/ssh_host_ed25519_key.pub /etc/childhurd/etc/ssh/ssh_host_ecdsa_key.pub @end example -These files are automatically sent to the guest Hurd VM when it boots, -including permissions. - -@cindex childhurd, offloading -@cindex Hurd, offloading -Having these files in place means that only a couple of things are -missing to allow the host to offload @code{i586-gnu} builds to the -childhurd: - -@enumerate -@item -Authorizing the childhurd's key on the host so that the host accepts -build results coming from the childhurd, which can be done like so: - -@example -guix archive --authorize < \ - /etc/childhurd/etc/guix/signing-key.pub -@end example - -@item -Adding the childhurd to @file{/etc/guix/machines.scm} (@pxref{Daemon -Offload Setup}). -@end enumerate - -We're working towards making that happen automatically---get in touch -with us at @email{guix-devel@@gnu.org} to discuss it! @end table @end deftp diff --git a/gnu/services/virtualization.scm b/gnu/services/virtualization.scm index 930c2ce702..076eca7ea2 100644 --- a/gnu/services/virtualization.scm +++ b/gnu/services/virtualization.scm @@ -27,6 +27,7 @@ (define-module (gnu services virtualization) #:use-module (gnu bootloader grub) #:use-module (gnu image) #:use-module (gnu packages admin) + #:use-module (gnu packages bash) #:use-module (gnu packages gdb) #:autoload (gnu packages gnupg) (guile-gcrypt) #:use-module (gnu packages package-management) @@ -52,6 +53,7 @@ (define-module (gnu services virtualization) #:use-module (guix store) #:use-module (guix utils) #:autoload (guix self) (make-config.scm) + #:autoload (guix platform) (platform-system) #:use-module (srfi srfi-9) #:use-module (srfi srfi-26) @@ -1063,6 +1065,26 @@ (define (secret-service-operating-system os) ;;; The Hurd in VM service: a Childhurd. ;;; +(define (operating-system-with-offloading-account os) + (define accounts + (list (user-group + (name "offloading") + (system? #t)) + (user-account + (name "offloading") + (group "offloading") + (system? #t) + (comment "Offloading privilege separation user") + (home-directory "/var/run/offloading") + (shell (file-append bash-minimal "/bin/sh"))))) + + (operating-system + (inherit os) + (services (cons (simple-service 'offloading-account + account-service-type + accounts) + (operating-system-user-services os))))) + (define %hurd-vm-operating-system (operating-system (inherit %hurd-default-operating-system) @@ -1115,14 +1137,21 @@ (define-record-type* (net-options hurd-vm-configuration-net-options ;list of string (thunked) (default (hurd-vm-net-options this-record))) + (offloading? hurd-vm-configuration-offloading? ;Boolean + (default #t)) (secret-root hurd-vm-configuration-secret-root ;string (default "/etc/childhurd"))) (define (hurd-vm-disk-image config) "Return a disk-image for the Hurd according to CONFIG. The secret-service is added to the OS specified in CONFIG." - (let* ((os (secret-service-operating-system - (hurd-vm-configuration-os config))) + (define transform + (compose secret-service-operating-system + (if (hurd-vm-configuration-offloading? config) + operating-system-with-offloading-account + identity))) + + (let* ((os (transform (hurd-vm-configuration-os config))) (disk-size (hurd-vm-configuration-disk-size config)) (type (lookup-image-type-by-name 'hurd-qcow2)) (os->image (image-type-constructor type))) @@ -1331,18 +1360,71 @@ (define ssh-directory (define guix-directory (string-append secret-directory "/etc/guix")) + (define offloading-ssh-key + #$(hurd-vm-configuration-offloading-ssh-key config)) + (unless (file-exists? ssh-directory) ;; Generate SSH host keys under SSH-DIRECTORY. (mkdir-p ssh-directory) (invoke #$(file-append openssh "/bin/ssh-keygen") "-A" "-f" secret-directory)) + (unless (or (not #$(hurd-vm-configuration-offloading? config)) + (file-exists? offloading-ssh-key)) + ;; Generate a user SSH key pair for the host to use when offloading + ;; to the guest. + (mkdir-p (dirname offloading-ssh-key)) + (invoke #$(file-append openssh "/bin/ssh-keygen") + "-t" "ed25519" "-N" "" + "-f" offloading-ssh-key) + + ;; Authorize it in the guest for user 'offloading'. + (let ((authorizations + (string-append ssh-directory + "/authorized_keys.d/offloading"))) + (mkdir-p (dirname authorizations)) + (copy-file (string-append offloading-ssh-key ".pub") + authorizations) + (chmod (dirname authorizations) #o555))) + (unless (file-exists? guix-directory) (invoke #$(initialize-hurd-vm-substitutes) guix-directory)) - ;; Authorize the archive signing key from GUIX-DIRECTORY in the host. - (invoke #$(authorize-guest-substitutes-on-host) guix-directory)))) + (when #$(hurd-vm-configuration-offloading? config) + ;; Authorize the archive signing key from GUIX-DIRECTORY in the host. + (invoke #$(authorize-guest-substitutes-on-host) guix-directory))))) + +(define (hurd-vm-configuration-offloading-ssh-key config) + "Return the name of the file containing the SSH key of user 'offloading'." + (string-append "/etc/guix/offload/ssh/childhurd" + (or (and=> (hurd-vm-configuration-id config) + number->string) + ""))) + +(define (hurd-vm-guix-extension config) + "When offloading is enabled, add this childhurd to the list of offlading +machines in /etc/guix/machines.scm." + (if (hurd-vm-configuration-offloading? config) + (let* ((image (hurd-vm-configuration-image config)) + (platform (image-platform image)) + (system (platform-system platform)) + (vm-ssh-key (string-append + (hurd-vm-configuration-secret-root config) + "/etc/ssh/ssh_host_ed25519_key.pub")) + (host-ssh-key (hurd-vm-configuration-offloading-ssh-key config))) + (guix-extension + (build-machines + (list #~(build-machine + (name "localhost") + (port #$(hurd-vm-port config %hurd-vm-ssh-port)) + (systems '(#$system)) + (host-key (call-with-input-file #$vm-ssh-key + (@ (ice-9 textual-ports) + get-string-all))) + (user "offloading") + (private-key #$host-ssh-key)))))) + (guix-extension))) (define hurd-vm-service-type (service-type @@ -1351,6 +1433,8 @@ (define hurd-vm-service-type hurd-vm-shepherd-service) (service-extension account-service-type (const %hurd-vm-accounts)) + (service-extension guix-service-type + hurd-vm-guix-extension) (service-extension activation-service-type hurd-vm-activation))) (default-value (hurd-vm-configuration)) diff --git a/gnu/tests/virtualization.scm b/gnu/tests/virtualization.scm index 599e58edf0..b79164737b 100644 --- a/gnu/tests/virtualization.scm +++ b/gnu/tests/virtualization.scm @@ -38,6 +38,7 @@ (define-module (gnu tests virtualization) #:use-module (guix gexp) #:use-module (guix records) #:use-module (guix store) + #:use-module (guix modules) #:export (%test-libvirt %test-qemu-guest-agent %test-childhurd)) @@ -244,11 +245,19 @@ (define %childhurd-os (permit-root-login #t))))))))))) (define (run-childhurd-test) + (define (import-module? module) + ;; This module is optional and depends on Guile-Gcrypt, do skip it. + (and (guix-module-name? module) + (not (equal? module '(guix store deduplication))))) + (define os (marionette-operating-system %childhurd-os - #:imported-modules '((gnu services herd) - (guix combinators)))) + #:imported-modules (source-module-closure + '((gnu services herd) + (guix combinators) + (gnu build install)) + #:select? import-module?))) (define vm (virtual-machine @@ -373,6 +382,31 @@ (define marionette (pk 'drv (string-trim-right drv))) drv))) + (test-assert "copy-on-write store" + ;; Set up a writable store. The root partition is already an + ;; overlayfs, which is not suitable as the bottom part of this + ;; additional overlayfs; thus, create a tmpfs for the backing + ;; store. + ;; TODO: Remove this when creates a writable + ;; store. + (marionette-eval + '(begin + (use-modules (gnu build install) + (guix build syscalls)) + + (mkdir "/run/writable-store") + (mount "none" "/run/writable-store" "tmpfs") + (mount-cow-store "/run/writable-store" "/backing-store") + (system* "df" "-hT")) + marionette)) + + (test-equal "offloading" + 0 + (marionette-eval + '(and (file-exists? "/etc/guix/machines.scm") + (system* "guix" "offload" "test")) + marionette)) + (test-end)))) (gexp->derivation "childhurd-test" test)) -- cgit v1.2.3