guix-devel/gnu/machine/ssh.scm

355 lines
14 KiB
Scheme
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2019 Jakob L. Kreuze <zerodaysfordays@sdf.lonestar.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (gnu machine ssh)
#:use-module (gnu machine)
#:autoload (gnu packages gnupg) (guile-gcrypt)
#:use-module (gnu system)
#:use-module (gnu system file-systems)
#:use-module (gnu system uuid)
#:use-module (guix diagnostics)
#:use-module (guix gexp)
#:use-module (guix i18n)
#:use-module (guix modules)
#:use-module (guix monads)
#:use-module (guix records)
#:use-module (guix remote)
#:use-module (guix scripts system reconfigure)
#:use-module (guix ssh)
#:use-module (guix store)
#:use-module (guix utils)
#:use-module (ice-9 match)
#:use-module (srfi srfi-19)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-35)
#:export (managed-host-environment-type
machine-ssh-configuration
machine-ssh-configuration?
machine-ssh-configuration
machine-ssh-configuration-host-name
machine-ssh-configuration-build-locally?
machine-ssh-configuration-port
machine-ssh-configuration-user
machine-ssh-configuration-session))
;;; Commentary:
;;;
;;; This module implements remote evaluation and system deployment for
;;; machines that are accessible over SSH and have a known host-name. In the
;;; sense of the broader "machine" interface, we describe the environment for
;;; such machines as 'managed-host.
;;;
;;; Code:
;;;
;;; Parameters for the SSH client.
;;;
(define-record-type* <machine-ssh-configuration> machine-ssh-configuration
make-machine-ssh-configuration
machine-ssh-configuration?
this-machine-ssh-configuration
(host-name machine-ssh-configuration-host-name) ; string
(build-locally? machine-ssh-configuration-build-locally?
(default #t))
(port machine-ssh-configuration-port ; integer
(default 22))
(user machine-ssh-configuration-user ; string
(default "root"))
(identity machine-ssh-configuration-identity ; path to a private key
(default #f))
(session machine-ssh-configuration-session ; session
(default #f)))
(define (machine-ssh-session machine)
"Return the SSH session that was given in MACHINE's configuration, or create
one from the configuration's parameters if one was not provided."
(maybe-raise-unsupported-configuration-error machine)
(let ((config (machine-configuration machine)))
(or (machine-ssh-configuration-session config)
(let ((host-name (machine-ssh-configuration-host-name config))
(user (machine-ssh-configuration-user config))
(port (machine-ssh-configuration-port config))
(identity (machine-ssh-configuration-identity config)))
(open-ssh-session host-name
#:user user
#:port port
#:identity identity)))))
;;;
;;; Remote evaluation.
;;;
(define (managed-host-remote-eval machine exp)
"Internal implementation of 'machine-remote-eval' for MACHINE instances with
an environment type of 'managed-host."
(maybe-raise-unsupported-configuration-error machine)
(remote-eval exp (machine-ssh-session machine)
#:build-locally?
(machine-ssh-configuration-build-locally?
(machine-configuration machine))))
;;;
;;; Safety checks.
;;;
(define (machine-check-file-system-availability machine)
"Raise a '&message' error condition if any of the file-systems specified in
MACHINE's 'system' declaration do not exist on the machine."
(define file-systems
(filter (lambda (fs)
(and (file-system-mount? fs)
(not (member (file-system-type fs)
%pseudo-file-system-types))
(not (memq 'bind-mount (file-system-flags fs)))))
(operating-system-file-systems (machine-operating-system machine))))
(define (check-literal-file-system fs)
(define remote-exp
#~(catch 'system-error
(lambda ()
(stat #$(file-system-device fs))
#t)
(lambda args
(system-error-errno args))))
(mlet %store-monad ((errno (machine-remote-eval machine remote-exp)))
(when (number? errno)
(raise (condition
(&message
(message (format #f (G_ "device '~a' not found: ~a")
(file-system-device fs)
(strerror errno)))))))
(return #t)))
(define (check-labeled-file-system fs)
(define remote-exp
(with-imported-modules '((gnu build file-systems))
#~(begin
(use-modules (gnu build file-systems))
(find-partition-by-label #$(file-system-label->string
(file-system-device fs))))))
(mlet %store-monad ((result (machine-remote-eval machine remote-exp)))
(unless result
(raise (condition
(&message
(message (format #f (G_ "no file system with label '~a'")
(file-system-label->string
(file-system-device fs))))))))
(return #t)))
(define (check-uuid-file-system fs)
(define remote-exp
(with-imported-modules (source-module-closure
'((gnu build file-systems)
(gnu system uuid)))
#~(begin
(use-modules (gnu build file-systems)
(gnu system uuid))
(define uuid
(string->uuid #$(uuid->string (file-system-device fs))))
(find-partition-by-uuid uuid))))
(mlet %store-monad ((result (machine-remote-eval machine remote-exp)))
(unless result
(raise (condition
(&message
(message (format #f (G_ "no file system with UUID '~a'")
(uuid->string (file-system-device fs))))))))
(return #t)))
(mbegin %store-monad
(mapm %store-monad check-literal-file-system
(filter (lambda (fs)
(string? (file-system-device fs)))
file-systems))
(mapm %store-monad check-labeled-file-system
(filter (lambda (fs)
(file-system-label? (file-system-device fs)))
file-systems))
(mapm %store-monad check-uuid-file-system
(filter (lambda (fs)
(uuid? (file-system-device fs)))
file-systems))))
(define (machine-check-initrd-modules machine)
"Raise a '&message' error condition if any of the modules needed by
'needed-for-boot' file systems in MACHINE are not available in the initrd."
(define file-systems
(filter file-system-needed-for-boot?
(operating-system-file-systems (machine-operating-system machine))))
(define (missing-modules fs)
(define remote-exp
(let ((device (file-system-device fs)))
(with-imported-modules (source-module-closure
'((gnu build file-systems)
(gnu build linux-modules)
(gnu system uuid)))
#~(begin
(use-modules (gnu build file-systems)
(gnu build linux-modules)
(gnu system uuid))
(define dev
#$(cond ((string? device) device)
((uuid? device) #~(find-partition-by-uuid
(string->uuid
#$(uuid->string device))))
((file-system-label? device)
#~(find-partition-by-label
(file-system-label->string #$device)))))
(missing-modules dev '#$(operating-system-initrd-modules
(machine-operating-system machine)))))))
(mlet %store-monad ((missing (machine-remote-eval machine remote-exp)))
(return (list fs missing))))
(mlet %store-monad ((device (mapm %store-monad missing-modules file-systems)))
(for-each (match-lambda
((fs missing)
(unless (null? missing)
(raise (condition
(&message
(message (format #f (G_ "~a missing modules ~{ ~a~}~%")
(file-system-device fs)
missing))))))))
device)
(return #t)))
(define (check-deployment-sanity machine)
"Raise a '&message' error condition if it is clear that deploying MACHINE's
'system' declaration would fail."
(mbegin %store-monad
(machine-check-file-system-availability machine)
(machine-check-initrd-modules machine)))
;;;
;;; System deployment.
;;;
(define (machine-boot-parameters machine)
"Monadic procedure returning a list of 'boot-parameters' for the generations
of MACHINE's system profile, ordered from most recent to oldest."
(define bootable-kernel-arguments
(@@ (gnu system) bootable-kernel-arguments))
(define remote-exp
(with-extensions (list guile-gcrypt)
(with-imported-modules (source-module-closure '((guix config)
(guix profiles)))
#~(begin
(use-modules (guix config)
(guix profiles)
(ice-9 textual-ports))
(define %system-profile
(string-append %state-directory "/profiles/system"))
(define (read-file path)
(call-with-input-file path
(lambda (port)
(get-string-all port))))
(map (lambda (generation)
(let* ((system-path (generation-file-name %system-profile
generation))
(boot-parameters-path (string-append system-path
"/parameters"))
(time (stat:mtime (lstat system-path))))
(list generation
system-path
time
(read-file boot-parameters-path))))
(reverse (generation-numbers %system-profile)))))))
(mlet* %store-monad ((generations (machine-remote-eval machine remote-exp)))
(return
(map (lambda (generation)
(match generation
((generation system-path time serialized-params)
(let* ((params (call-with-input-string serialized-params
read-boot-parameters))
(root (boot-parameters-root-device params))
(label (boot-parameters-label params)))
(boot-parameters
(inherit params)
(label
(string-append label " (#"
(number->string generation) ", "
(let ((time (make-time time-utc 0 time)))
(date->string (time-utc->date time)
"~Y-~m-~d ~H:~M"))
")"))
(kernel-arguments
(append (bootable-kernel-arguments system-path root)
(boot-parameters-kernel-arguments params))))))))
generations))))
(define (deploy-managed-host machine)
"Internal implementation of 'deploy-machine' for MACHINE instances with an
environment type of 'managed-host."
(maybe-raise-unsupported-configuration-error machine)
(mlet %store-monad ((_ (check-deployment-sanity machine))
(boot-parameters (machine-boot-parameters machine)))
(let* ((os (machine-operating-system machine))
(eval (cut machine-remote-eval machine <>))
(menu-entries (map boot-parameters->menu-entry boot-parameters))
(bootloader-configuration (operating-system-bootloader os))
(bootcfg (operating-system-bootcfg os menu-entries)))
(mbegin %store-monad
(switch-to-system eval os)
(upgrade-shepherd-services eval os)
(install-bootloader eval bootloader-configuration bootcfg)))))
;;;
;;; Environment type.
;;;
(define managed-host-environment-type
(environment-type
(machine-remote-eval managed-host-remote-eval)
(deploy-machine deploy-managed-host)
(name 'managed-host-environment-type)
(description "Provisioning for machines that are accessible over SSH
and have a known host-name. This entails little more than maintaining an SSH
connection to the host.")))
(define (maybe-raise-unsupported-configuration-error machine)
"Raise an error if MACHINE's configuration is not an instance of
<machine-ssh-configuration>."
(let ((config (machine-configuration machine))
(environment (environment-type-name (machine-environment machine))))
(unless (and config (machine-ssh-configuration? config))
(raise (condition
(&message
(message (format #f (G_ "unsupported machine configuration '~a'
for environment of type '~a'")
config
environment))))))))