1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
| | ;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2015 David Thompson <davet@gnu.org>
;;; Copyright © 2016, 2017, 2019 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2019 Arun Isaac <arunisaac@systemreboot.net>
;;;
;;; 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 system linux-container)
#:use-module (ice-9 match)
#:use-module (srfi srfi-1)
#:use-module (guix config)
#:use-module (guix store)
#:use-module (guix gexp)
#:use-module (guix derivations)
#:use-module (guix monads)
#:use-module (guix modules)
#:use-module (gnu build linux-container)
#:use-module (gnu services)
#:use-module (gnu services base)
#:use-module (gnu system)
#:use-module (gnu system file-systems)
#:export (system-container
containerized-operating-system
container-script))
(define* (container-essential-services os #:key shared-network?)
"Return a list of essential services corresponding to OS, a
non-containerized OS. This procedure essentially strips essential services
from OS that are needed on the bare metal and not in a container."
(define base
(remove (lambda (service)
(memq (service-kind service)
(list (service-kind %linux-bare-metal-service)
firmware-service-type
system-service-type)))
(operating-system-essential-services os)))
(cons (service system-service-type
(let ((locale (operating-system-locale-directory os)))
(with-monad %store-monad
(return `(("locale" ,locale))))))
;; If network is to be shared with the host, remove network
;; configuration files from etc-service.
(if shared-network?
(modify-services base
(etc-service-type
files => (remove
(match-lambda
((filename _)
(member filename
(map basename %network-configuration-files))))
files)))
base)))
(define* (containerized-operating-system os mappings #:key shared-network?)
"Return an operating system based on OS for use in a Linux container
environment. MAPPINGS is a list of <file-system-mapping> to realize in the
containerized OS."
(define user-file-systems
(remove (lambda (fs)
(let ((target (file-system-mount-point fs))
(source (file-system-device fs)))
(or (string=? target (%store-prefix))
(string=? target "/")
(and (string? source)
(string-prefix? "/dev/" source))
(string-prefix? "/dev/" target)
(string-prefix? "/sys/" target))))
(operating-system-file-systems os)))
(define (mapping->fs fs)
(file-system (inherit (file-system-mapping->bind-mount fs))
(needed-for-boot? #t)))
(define useless-services
;; Services that make no sense in a container. Those that attempt to
;; access /dev/tty[0-9] in particular cannot work in a container.
(append (list console-font-service-type
mingetty-service-type
agetty-service-type)
;; Remove nscd service if network is shared with the host.
(if shared-network?
(list nscd-service-type)
(list))))
(define shared-network-file-mappings
;; Files to map if network is to be shared with the host
(append %network-file-mappings
(let ((nscd-run-directory "/var/run/nscd"))
(if (file-exists? nscd-run-directory)
(list (file-system-mapping
(source nscd-run-directory)
(target nscd-run-directory)))
(list)))))
;; (write shared-network-file-mappings)
;; (newline)
(operating-system
(inherit os)
(swap-devices '()) ; disable swap
(essential-services (container-essential-services
os #:shared-network? shared-network?))
(services (remove (lambda (service)
(memq (service-kind service)
useless-services))
(operating-system-user-services os)))
(file-systems (append (map mapping->fs
(cons %store-mapping
(append mappings
(if shared-network?
shared-network-file-mappings
(list)))))
%container-file-systems
user-file-systems))))
(define* (container-script os #:key (mappings '()) shared-network?)
"Return a derivation of a script that runs OS as a Linux container.
MAPPINGS is a list of <file-system> objects that specify the files/directories
that will be shared with the host system."
(let* ((os (containerized-operating-system
os
mappings
#:shared-network? shared-network?))
(file-systems (filter file-system-needed-for-boot?
(operating-system-file-systems os)))
(specs (map file-system->spec file-systems)))
(define script
(with-imported-modules (source-module-closure
'((guix build utils)
(gnu build linux-container)))
#~(begin
(use-modules (gnu build linux-container)
(gnu system file-systems) ;spec->file-system
(guix build utils))
(call-with-container (map spec->file-system '#$specs)
(lambda ()
(setenv "HOME" "/root")
(setenv "TMPDIR" "/tmp")
(setenv "GUIX_NEW_SYSTEM" #$os)
(for-each mkdir-p '("/run" "/bin" "/etc" "/home" "/var"))
(primitive-load (string-append #$os "/boot")))
;; A range of 65536 uid/gids is used to cover 16 bits worth of
;; users and groups, which is sufficient for most cases.
;;
;; See: http://www.freedesktop.org/software/systemd/man/systemd-nspawn.html#--private-users=
#:host-uids 65536
#:namespaces (if #$shared-network?
(delq 'net %namespaces)
%namespaces)))))
(gexp->script "run-container" script)))
|