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1<!doctype debiandoc system>
2<!-- -*- mode: sgml; mode: fold -*- -->
3<book>
4<title>Using APT Offline</title>
5
6<author>Jason Gunthorpe <email>jgg@debian.org</email></author>
7<version>$Id: offline.sgml,v 1.3 2001/02/20 07:03:17 jgg Exp $</version>
8
9<abstract>
10This document describes how to use APT in a non-networked environment,
11specifically a 'sneaker-net' approach for performing upgrades.
12</abstract>
13
14<copyright>
15Copyright &copy; Jason Gunthorpe, 1999.
16<p>
17"APT" and this document are free software; you can redistribute them and/or
18modify them under the terms of the GNU General Public License as published
19by the Free Software Foundation; either version 2 of the License, or (at your
20option) any later version.
21
22<p>
23For more details, on Debian GNU/Linux systems, see the file
24/usr/doc/copyright/GPL for the full license.
25</copyright>
26
27<toc sect>
28
29<chapt>Introduction
30<!-- Overview {{{ -->
31<!-- ===================================================================== -->
32<sect>Overview
33
34<p>
35Normally APT requires direct access to a Debian archive, either from a local
36media or through a network. Another common complaint is that a Debian machine
37is on a slow link, such as a modem and another machine has a very fast
38connection but they are physically distant.
39
40<p>
41The solution to this is to use large removable media such as a Zip disc or a
42SuperDisk disc. These discs are not large enough to store the entire Debian
43archive but can easily fit a subset large enough for most users. The idea
44is to use APT to generate a list of packages that are required and then fetch
45them onto the disc using another machine with good connectivity. It is
46even possible to use another Debian machine with APT or to use a completely
47different OS and a download tool like wget.
48
49<p>
50This is achieved by creatively manipulating the APT configuration file. The
51essential premis to tell APT to look on a disc for it's archive files. Note
52that the disc should be formated with a filesystem that can handle long file
53names such as ext2, fat32 or vfat.
54
55</sect>
56 <!-- }}} -->
57
58<chapt>Using APT on both machines
59<!-- Overview {{{ -->
60<!-- ===================================================================== -->
61<sect>Overview
62
63<p>
64APT being available on both machines gives the simplest configuration. The
65basic idea is to place a copy of the status file on the disc and use the
66remote machine to fetch the latest package files and decide which packages to
67download. The disk directory structure should look like:
68
69<example>
70 /disc/
71 archives/
72 partial/
73 lists/
74 partial/
75 status
76 sources.list
77 apt.conf
78</example>
79
80</sect>
81 <!-- }}} -->
82<!-- The configuartion file {{{ -->
83<!-- ===================================================================== -->
84<sect>The configuration file
85
86<p>
87The configuration file should tell APT to store its files on the disc and
88to use the configuration files on the disc as well. The sources.list should
89contain the proper sites that you wish to use from the remote machine, and
90the status file should be a copy of <em>/var/lib/dpkg/status</em>. Please note,
91if you are using a local archive you must use copy URIs, the syntax is identical
92to file URIs.
93
94<p>
95<em>apt.conf</em> must contain the necessary information to make APT use the
96disc:
97
98<example>
99 APT
100 {
101 /* This is not necessary if the two machines are the same arch, it tells
102 the remote APT what architecture the Debian machine is */
103 Architecture "i386";
104
105 Get::Download-Only "true";
106 };
107
108 Dir
109 {
110 /* Use the disc for state information and redirect the status file from
111 the /var/lib/dpkg default */
112 State "/disc/";
113 State::status "status";
114
115 // Binary caches will be stored locally
116 Cache::archives "/disc/archives/";
117
118 // Location of the source list.
119 Etc "/disc/";
120 };
121</example>
122
123More details can be seen by examining the apt.conf man page and the sample
124configuration file in <em>/usr/doc/apt/examples/apt.conf</em>.
125
126<p>
127On the remote Debian machine the first thing to do is mount the disc and copy
128<em>/var/lib/dpkg/status</em> to it. You will also need to create the directories
129outlined in the Overview, <em>archives/partial/</em> and <em>lists/partial/</em>
130Then take the disc to the remote machine and configure the sources.list.
131On the remote machine execute the following:
132
133<example>
134 # export APT_CONFIG="/disc/apt.conf"
135 # apt-get update
136 [ APT fetches the package files ]
137 # apt-get dist-upgrade
138 [ APT fetches all the packages needed to upgrade your machine ]
139</example>
140
141The dist-upgrade command can be replaced with any-other standard APT commands,
142particularly dselect-upgrad. You can even use an APT front end such as
143<em>dselect</em> However this presents a problem in communicating your
144selections back to the local computer.
145
146<p>
147Now the disc contains all of the index files and archives needed to upgrade
148the Debian machine. Take the disc back and run:
149
150<example>
151 # export APT_CONFIG="/disc/apt.conf"
152 # apt-get check
153 [ APT generates a local copy of the cache files ]
154 # apt-get --no-d -o dir::etc::status=/var/lib/dpkg/status dist-upgrade
155 [ Or any other APT command ]
156</example>
157
158<p>
159It is necessary for proper function to re-specify the status file to be the
160local one. This is very important!
161
162<p>
163If you are using dselect you can do the very risky operation of copying
164disc/status to /var/lib/dpkg/status so that any selections you made on the
165remote machine are updated. I highly recommend that people only make selections
166on the local machine - but this may not always be possible. DO NOT copy
167the status file if dpkg or APT have been run in the mean time!!
168
169</sect>
170 <!-- }}} -->
171
172<chapt>Using APT and wget
173<!-- Overview {{{ -->
174<!-- ===================================================================== -->
175<sect>Overview
176
177<p>
178<em>wget</em> is a popular and portable download tool that can run on nearly
179any machine. Unlike the method above this requires that the Debian machine
180already has a list of available packages.
181
182<p>
183The basic idea is to create a disc that has only the archive files downloaded
184from the remote site. This is done by using the --print-uris option to apt-get
185and then preparing a wget script to actually fetch the packages.
186
187</sect>
188 <!-- }}} -->
189<!-- Operation {{{ -->
190<!-- ===================================================================== -->
191<sect>Operation
192
193<p>
194Unlike the previous technique no special configuration files are required. We
195merely use the standard APT commands to generate the file list.
196
197<example>
198 # apt-get dist-upgrade
199 [ Press no when prompted, make sure you are happy with the actions ]
200 # apt-get -qq --print-uris dist-upgrade > uris
201 # awk '{print "wget -O " $2 " " $1}' < uris > /disc/wget-script
202</example>
203
204Any command other than dist-upgrade could be used here, including
205dselect-upgrade.
206
207<p>
208The /disc/wget-script file will now contain a list of wget commands to execute
209in order to fetch the necessary archives. This script should be run with the
210current directory as the disc's mount point so as to save the output on the
211disc.
212
213<p>
214The remote machine would do something like
215
216<example>
217 # cd /disc
218 # sh -x ./wget-script
219 [ wait.. ]
220</example>
221
222Once the archives are downloaded and the disc returned to the Debian machine
223installation can proceed using,
224
225<example>
226 # apt-get -o dir::cache::archives="/disc/" dist-upgrade
227</example>
228
229Which will use the already fetched archives on the disc.
230
231</sect>
232 <!-- }}} -->
233</book>