/[gentoo]/xml/htdocs/doc/en/uml.xml
Gentoo

Diff of /xml/htdocs/doc/en/uml.xml

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

Revision 1.1 Revision 1.31
1<?xml version='1.0'?> 1<?xml version='1.0' encoding="UTF-8"?>
2<?xml-stylesheet href="/xsl/guide.xsl" type="text/xsl"?> 2<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/uml.xml,v 1.31 2011/09/04 17:53:40 swift Exp $ -->
3 3
4<!DOCTYPE guide SYSTEM "/dtd/guide.dtd"> 4<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
5 5
6<guide link="/doc/uml.html"> 6<guide>
7<title>Gentoo Linux Developer's guide to system testing with User-Mode Linux</title> 7<title>Gentoo Linux Developer's guide to system testing with User-Mode Linux</title>
8
9<author title="Editor">
8<author title="Editor"><mail link="g2boojum@gentoo.org">Grant Goodyear</mail></author> 10 <mail link="g2boojum@gentoo.org">Grant Goodyear</mail>
11</author>
12<author title="Editor"><!-- zhen@gentoo.org -->
13 John Davis
14</author>
15<author title="Editor">
16 <mail link="swift@gentoo.org">Sven Vermeulen</mail>
17</author>
18<author title="Editor">
19 <mail link="bennyc@gentoo.org">Benny Chuang</mail>
20</author>
9 21
10<abstract> 22<abstract>
11 This guide shows Gentoo Linux developers how to set up and use 23This guide shows Gentoo Linux developers how to set up and use
12 user-mode linux for testing potentially system-breaking changes. 24user-mode linux for testing potentially system-breaking changes.
13</abstract> 25</abstract>
14 26
27<!-- The content of this document is licensed under the CC-BY-SA license -->
28<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
29<license/>
30
15<version>0.05</version> 31<version>0.16</version>
16<date>5 Mar 2002</date> 32<date>2008-03-01</date>
17 33
18<chapter> 34<chapter>
19<title>Obtaining User-Mode Linux</title> 35<title>Obtaining User-Mode Linux</title>
20<section> 36<section>
21<body> 37<body>
38
39<impo>
40Before you can use user-mode Linux, you <e>must</e> be using a non-NPTL
41profile, and you must be using &lt;<c>glibc</c>-2.4. Follow the instructions
42for <uri link="/doc/en/gentoo-upgrading.xml#instructions">changing
43profiles</uri>. You will need to run <c>emerge -e world</c> after switching to
44a non-NPTL profile.
45</impo>
46
47<p>
22<p>As the user-mode linux website 48As the user-mode Linux website
23(<uri>http://user-mode-linux.sourceforge.net</uri>) 49(<uri>http://user-mode-linux.sourceforge.net</uri>) states, user-modeL linux
24states, user-mode linux
25allows a user to "run Linux inside itself". Specifically, 50allows a user to "run Linux inside itself". Specifically,
26user-mode linux provides a virtual machine on which a user can "[r]un buggy 51user-mode linux provides a virtual machine on which a user can "[r]un buggy
27software, experiment with new Linux kernels or distributions, and poke around 52software, experiment with new Linux kernels or distributions, and poke around
28in the internals of Linux, all without risking your main Linux setup." Changes 53in the internals of Linux, all without risking your main Linux setup."
29to Gentoo core packages such as <e>sys-apps/baselayout</e> or <e>sys-libs/glibc</e> 54Experimental changes to Gentoo core packages such as <e>sys-apps/baselayout</e>
30have the potential to break the system and render it unbootable; with user-mode 55or <e>sys-libs/glibc</e> have the potential to break the system and render it
31linux we can test these changes without having to worry about breaking the live 56unbootable; with user-mode Linux we can test these changes without having to
32system. 57worry about breaking the live system.
33</p>
34<p> 58</p>
35Installing user-mode linux is essentially identical to a normal kernel 59
36install. First install the kernel sources (appropriately patched for
37user-mode linux), and then configure the user-mode linux kernel in the
38usual fashion:
39</p> 60<p>
61Most 2.6 kernels have UML support. Although you can use your current kernel
62sources, it might be wiser to keep the UML kernel tree(s) separate. After all,
63you'll be building a new kernel with a different configuration and you might
64want to have heterogenous systems on your main Linux system (several different
65UML kernels).
66</p>
67
40<pre> 68<p>
41# <i>emerge sys-kernel/usermode-sources</i> 69So download a nice kernel tree (like the vanilla one from <uri
70link="http://www.kernel.org">kernel.org</uri>) and extract it to some local
71development location.
72</p>
73
74<p>
75Next, configure this UML kernel as you would do for any other system, but append
76<e>ARCH=um</e> so that the kernel build software knows that the kernel
77is meant to run as a guest process on the main system.
78</p>
79
80<pre caption="Building the UML kernel">
42# <i>cd /usr/src/uml/linux</i> 81# <i>cd /srv/aegis/src/uml-linux</i>
43# <i>make menuconfig <comment>ARCH=um</comment></i> 82# <i>make menuconfig <comment>ARCH=um</comment></i>
44# <i>make linux <comment>ARCH=um</comment></i> 83# <i>make linux <comment>ARCH=um</comment></i>
45# <i>cp linux /usr/local/bin/linux</i> 84# <i>cp linux /usr/local/bin/linux</i>
46</pre> 85</pre>
86
87<warn>
47<warn>The <e>ARCH=um</e> fragment is <e>extremely</e> important!</warn> 88The <e>ARCH=um</e> fragment is <e>extremely</e> important!
48<impo> 89</warn>
90
91<p>
92On a default Gentoo system, <path>/usr/local/bin</path> is in your <c>$PATH</c>.
93If it isn't, you should find a definition of <c>PATH</c> in the
94<path>/etc/profile</path> and fix it:
95</p>
96
97<pre caption="Verifying $PATH">
98$ <i>echo $PATH | grep /usr/local/bin</i>
99</pre>
100
101<pre caption="Sample definition of $PATH in /etc/profile">
102PATH="/usr/local/bin:/usr/bin:/bin:${PATH}"
103</pre>
104
105<p>
106Don't forget to run <c>source /etc/profile</c> for the change to take effect.
107</p>
108
109<p>
49For the user-mode linux kernel to properly boot a Gentoo system the 110For the user-mode Linux kernel to properly boot a Gentoo system the
50kernel needs to be configured to <e>not</e> automatically mount 111kernel needs to be configured to <e>not</e> automatically mount
51<path>/dev</path> (devfs) by default. 112<path>/dev</path> (devfs) by default. Also, you will almost certainly
52Also, you will almost certainly
53want to make sure that you have <e>tmpfs</e> (the "Virtual Memory 113want to make sure that you have <e>tmpfs</e> (the "Virtual Memory
54Filesystem") compiled in, since by default the Gentoo linux bootscripts 114Filesystem") compiled in, since by default the Gentoo Linux bootscripts
55store their information in a small tmpfs partition. 115store their information in a small tmpfs partition.
56(The binary kernels available 116(The binary kernels available from the user-mode website do automatically
57from the user-mode website do automatically mount <path>/dev</path>, 117mount <path>/dev</path>, and they don't have tmpfs compiled in; don't bother
58and they don't have tmpfs compiled in; don't bother with them.) 118with them).
59</impo> 119</p>
120
121<p>
60<p>I highly recommend reading the user-mode linux documentation, but the 122I highly recommend reading the user-mode linux documentation, but the
61basic idea is that running the <path>/usr/local/bin/linux</path> program 123basic idea is that running the <path>/usr/local/bin/linux</path> program
62boots the user-mode kernel and tries to bring up the system stored in 124boots the user-mode kernel and tries to bring up the system stored in
63the file <path>root_fs</path> that should be located in the current working 125the file <path>root_fs</path> that should be located in the current working
64directory.</p> 126directory.
127</p>
128
129<p>
65<p>It won't hurt to also install the user-mode linux tools.</p> 130It won't hurt to also install the user-mode Linux tools.
66<pre> 131</p>
132
133<pre caption="Installing UML tools">
67# <i>emerge sys-apps/usermode-utilities</i> 134# <i>emerge sys-apps/usermode-utilities</i>
68</pre> 135</pre>
136
137<p>
69<p>These tools facilitate networking (among other things) 138These tools facilitate networking (among other things) between the user-mode
70between the user-mode linux virtual system 139Linux virtual system and the host Linux system.
71and the host Linux system.</p> 140</p>
141
72</body> 142</body>
73</section> 143</section>
74</chapter> 144</chapter>
75 145
76<chapter> 146<chapter>
77<title>Creating <path>root_fs</path></title> 147<title>Creating root_fs</title>
78
79<section> 148<section>
80<title>Making the Gentoo chroot</title> 149<title>Making the Gentoo chroot</title>
81<body> 150<body>
151
82<p> 152<p>
83The <path>root_fs</path> file needed for user-mode linux is 153The <path>root_fs</path> file needed for user-mode linux is
84a single file that contains an entire Gentoo Linux filesystem. 154a single file that contains an entire Gentoo Linux filesystem.
85To generate this file you will need to have Loopback device 155To generate this file you will need to have Loopback device
86support enabled in the host (non-user-mode) kernel. 156support enabled in the host (non-user-mode) kernel.
87</p> 157</p>
158
159<p>
88<p>Generating the <path>root_fs</path> file itself will be 160Generating the <path>root_fs</path> file itself will be
89our last step. First we will generate a Gentoo filesystem in 161our last step. First we will generate a Gentoo filesystem in
90an ordinary chroot. We need the build tarball available, which 162an ordinary chroot. We need the stage tarball available, which
91could be downloaded separately, extracted from a build cd, or 163could be downloaded separately, extracted from an Installation CD, or
92extracted from a build .iso. 164extracted from an Installation CD .iso.
93</p> 165</p>
166
94<pre caption="Mounting a build .iso"> 167<pre caption="Mounting an Installation CD .iso">
95# <i>mkdir /mnt/loop</i> 168# <i>mkdir /mnt/loop</i>
96# <i>mount -o loop /path/to/build-&lt;TAB&gt;.iso /mnt/loop</i> 169# <i>mount -o loop /path/to/install-&lt;TAB&gt;.iso /mnt/loop</i>
97</pre> 170</pre>
171
98<p> 172<p>
99Setting up the chroot is essentially identical to an ordinary Gentoo 173Setting up the chroot is essentially identical to an ordinary Gentoo
100Linux build. 174Linux build.
101</p> 175</p>
102<pre> 176
177<pre caption="Creating the Gentoo chroot mount">
103# <i>mkdir /mnt/gentoo</i> 178# <i>mkdir /mnt/gentoo</i>
104# <i>cd /mnt/gentoo</i> 179# <i>cd /mnt/gentoo</i>
105# <i>tar xvjpf /path/to/build-&lt;TAB&gt;.tar.bz2</i> 180# <i>tar xvjpf /path/to/stage&lt;TAB&gt;.tar.bz2</i>
106</pre> 181</pre>
182
107<p> 183<p>
108Go ahead and unmount the .iso. You don't need it anymore. 184Go ahead and unmount the .iso. You don't need it anymore.
109</p> 185</p>
110<pre> 186
111# <i>cp /etc/resolv.conf /mnt/gentoo/etc/</i>
112# <i>mount -o bind /proc /mnt/gentoo/proc</i>
113# <i>mkdir -p /mnt/gentoo/usr/portage/distfiles</i>
114# <i>mkdir -p /mnt/gentoo/usr/portage/packages</i>
115# <i>mount -o bind /usr/portage/distfiles /mnt/gentoo/usr/portage/distfiles</i>
116# <i>mount -o bind /usr/portage/packages /mnt/gentoo/usr/portage/packages</i>
117# <i>chroot /mnt/gentoo /bin/bash</i>
118# <i>env-update</i>
119# <i>source /etc/profile</i>
120</pre>
121<p>
122By bind-mounting <path>/usr/portage/distfiles</path> and
123<path>/usr/portage/packages</path> we avoid having to download
124or build packages that are already present on the Gentoo host.
125</p> 187<p>
188Build the system in the usual fashion: chroot into <path>/mnt/gentoo</path> and
189follow the Gentoo installation instructions.
126<p> 190</p>
127Bootstrap and build the system in the usual fashion: 191
128</p>
129<pre>
130# <i>emerge rsync</i>
131# <i>cd /usr/portage</i>
132# <i>nano -w /etc/make.conf</i>
133# <i>nano -w /etc/make.profile/packages</i>
134# <i>nano -w /usr/portage/profiles/package.mask</i>
135# <i>scripts/bootstrap.sh &amp;&amp; emerge --usepkg system</i>
136</pre>
137<warn>
138The <path>/etc/make.profile/packages</path> file needs to be
139edited to remove grub from the default system (just remove the "*"
140from the beginning of the "*sys-apps/grub" line). The grub ebuild
141tries to mount the /boot partition, which will fail in our chroot.
142</warn>
143<note>
144Make sure you examine <path>/etc/make.profile/packages</path>
145and <path>/usr/portage/profiles/package.mask</path> to be sure that
146any to-be-tested packages that you want to install aren't masked out.
147As currently written, <path>scripts/bootstrap.sh</path> will compile
148the bootstrap packages from source. To use already-existing packages,
149add <c>alias emerge="emerge --usepkg"</c> somewhere near the top of
150the bootstrap script.
151</note>
152<p> 192<p>
153Add any additional packages you desire. Feel free to give your virtual 193Add any additional packages you desire. Feel free to give your virtual
154Gentoo system a hostname, if you so desire. In <path>/etc/fstab</path> 194Gentoo system a hostname, if you so desire. In <path>/etc/fstab</path>
155you will want <path>/dev/ROOT</path> to be <path>/dev/ubd/0</path>, with 195you will want <path>/dev/ROOT</path> to be <path>/dev/ubda</path>, with
156a fs type of either ext2, ext3, or reiserfs. Set <path>/dev/SWAP</path> 196a fs type of either ext2, ext3, or reiserfs. Set <path>/dev/SWAP</path>
157to be <path>/dev/ubd/1</path>, and comment out <path>/dev/BOOT</path>. 197to be <path>/dev/ubdb</path>, and comment out <path>/dev/BOOT</path>.
198</p>
199
158</p> 200<p>
201At this point, remember to set your root password.
202</p>
203
204<pre caption="Setting root password">
205# <i>passwd</i>
206</pre>
207
208<p>
209Now we need to make some changes to the boot scripts. Remove consolefont and
210keymaps from the boot runlevel:
211</p>
212
213<pre caption="Removing unneeded initscripts">
214# <i>rc-update del consolefont boot</i>
215# <i>rc-update del keymaps boot</i>
216</pre>
217
159<p> 218<p>
160Exit the chroot, unmount all of the bind mounts, 219Exit the chroot, unmount all of the bind mounts,
161tar up the new Gentoo distro, and clean up: 220tar up the new Gentoo distro, and clean up.
162</p> 221</p>
163<pre> 222
164# <i>exit</i> 223<pre caption="Finalising the installation">
165# <i>umount /mnt/gentoo/usr/portage/distfiles</i>
166# <i>umount /mnt/gentoo/usr/portage/packages</i>
167# <i>umount /mnt/gentoo/proc</i>
168# <i>du -ks /mnt/gentoo</i> 224# <i>cd /mnt/gentoo</i>
169261744 /mnt/gentoo
170# <i>tar cvjpf ~/gentoo.tbz2 *</i> 225# <i>tar cvjpf ~/gentoo.tbz2 *</i>
171# <i>cd</i> 226# <i>cd</i>
172# <i>rm -rf /mnt/gentoo</i> 227# <i>rm -rf /mnt/gentoo</i>
173</pre> 228</pre>
174</body>
175</section>
176 229
230</body>
177<section> 231</section>
232<section>
178<title>Making <path>root_fs</path></title> 233<title>Making root_fs</title>
179<body> 234<body>
235
180<p> 236<p>
181Our Gentoo chroot is nearly 300 MB in size, so 237Our Gentoo chroot is nearly 300 MB in size, so
182<path>root_fs</path> needs to be at least that size. 238<path>root_fs</path> needs to be at least that size.
183We'll choose 0.5 GB as a reasonable size. 239We'll choose 0.5 GB as a reasonable size.
184</p> 240</p>
185<pre> 241
242<pre caption="Creating UML files">
186# <i>dd if=/dev/zero of=root_fs seek=500 count=1 bs=1M</i> 243# <i>dd if=/dev/zero of=root_fs seek=500 count=1 bs=1M</i>
187# <i>mke2fs -F root_fs</i> 244# <i>mke2fs -F root_fs</i>
188# <i>mount -o loop root_fs /mnt/loop</i> 245# <i>mount -o loop root_fs /mnt/loop</i>
189# <i>tar xvjpf gentoo.tbz2 -C /mnt/loop</i> 246# <i>tar xvjpf gentoo.tbz2 -C /mnt/loop</i>
190# <i>umount /mnt/loop</i> 247# <i>umount /mnt/loop</i>
191</pre> 248</pre>
249
192<p> 250<p>
193It would also be nice to have a 0.5 GB swap partition. 251It would also be nice to have a 0.5 GB swap partition.
194</p> 252</p>
195<pre> 253
254<pre caption="Create swap partition">
196# <i>dd if=/dev/zero of=swap_fs seek=500 count=1 bs=1M</i> 255# <i>dd if=/dev/zero of=swap_fs seek=500 count=1 bs=1M</i>
197# <i>mkswap -f swap_fs</i> 256# <i>mkswap -f swap_fs</i>
198</pre> 257</pre>
258
199<p> 259<p>
200Now see if it works! 260Now see if it works!
201</p> 261</p>
202<pre> 262
263<pre caption="Start UML kernel thread">
203# <i>linux ubd0=root_fs ubd1=swap_fs</i> 264# <i>linux ubd0=root_fs ubd1=swap_fs</i>
204</pre> 265</pre>
266
267<p>
268User-mode Linux uses xterms for the virtual consoles that
269are run at boot time, so you need to make sure that the
270terminal from which you run user-mode Linux has $DISPLAY
271properly set (along with proper xhost/xauth permissions).
272</p>
273
274<p>
275With any luck you should be able to log into your user-mode Linux
276Gentoo system. The only thing keeping this user-mode Linux version
277of Gentoo from being fully functional is networking from the virtual
278machine to the host.
279</p>
280
205<note> 281<note>
206User-mode linux uses xterms for the virtual consoles that 282If you receive "No space left on device" errors, you may need to allocate more
207are run at boot time, so you need to make sure that the 283memory to your user mode system by appending <c>mem=xxxMB</c> to the end of the
208terminal from which you run user-mode linux has $DISPLAY 284kernel thread line. For example: <c>linux ubd0=root_fs ubd1=swap_fs
209properly set (along with proper xhost/xauth permissions). 285mem=128MB</c>.
210</note> 286</note>
211<p> 287
212With any luck you should be able to log into your user-mode linux
213Gentoo system. The only thing keeping this user-mode linux version
214of Gentoo from being fully functional is networking from the virtual
215machine to the host. Such networking is supposed to be trivial,
216but I have yet to get it to work for me. Should you find a workable
217solution, please let me know!
218</p>
219</body> 288</body>
220</section> 289</section>
221</chapter> 290</chapter>
222 291
223<chapter> 292<chapter>
224<title>Networking</title> 293<title>Networking</title>
225
226<section> 294<section>
295<title>Using an Existing Network</title>
227<body> 296<body>
228<p> 297
229Thanks to Martin Schlemmer (Azarah), I now know how
230to get networking to function from within a user-mode
231system. The idea is that we set up a private network
232consisting of the user-mode system and the host system,
233and then the user-mode system routes all of its packets
234to the host, which then forwards packets to the net.
235Make sure that the host kernel has
236Networking --> IP: Netfilter Configuration --> IP tables support
237--> Full NAT --> MASQUERADE target support and
238Network Device Support --> Ethertap network tap
239compiled as modules; then do the following on the
240<e>host</e> machine:
241</p> 298<p>
299Make sure that the host kernel has the following settings compiled as modules:
300</p>
301
302<pre caption="Host kernel configuration">
303Networking --&gt;
304 IP: Netfilter Configuration --&gt;
305 IP tables support --&gt;
306 Full NAT --&gt;
307 &lt;M&gt; MASQUERADE target support
308
309 Network Device Support --&gt;
310 &lt;M&gt; TUN/TAP Support
242<pre> 311</pre>
312
313<p>
314Run the following commands on the <e>host</e> machine:
315</p>
316
317<pre caption="Setup networking">
243# <i>modprobe ethertap</i> 318# <i>modprobe tun</i>
319<comment>(If you receive a FATAL error here, try deleting /dev/net/tun and retry)</comment>
244# <i>modprobe iptable_nat</i> 320# <i>modprobe iptable_nat</i>
245# <i>iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE</i> 321# <i>iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE</i>
246# <i>echo 1 > /proc/sys/net/ipv4/ip_forward</i> 322# <i>echo 1 &gt; /proc/sys/net/ipv4/ip_forward</i>
247</pre> 323</pre>
324
248<p> 325<p>
249The iptables line sets up IP Masquerading between the private 326The iptables line sets up IP Masquerading between the private
250network that our user-mode system will be on and the internet 327network that our user-mode system will be on and the internet
251(reachable via <c>eth0</c> in our case). The echo line then 328(reachable via <c>eth0</c> in our case). The echo line then
252turns on packet forwarding between the private network and the 329turns on packet forwarding between the private network and the
253interface that the default gateway is on (eth0 for us). 330interface that the default gateway is on (eth0 for us).
254</p> 331</p>
332
255<p> 333<p>
256Now we bring up the user-mode system and see if networking 334Now we bring up the user-mode system and see if networking
257is functional. 335is functional.
258</p> 336</p>
259<pre> 337
338<pre caption="Get UML up and running">
260# <i>linux ubd0=root_fs ubd1=swap_fs eth0=ethertap,tap0,,192.168.0.254</i> 339# <i>linux ubd0=root_fs ubd1=swap_fs eth0=tuntap,,,192.168.0.254</i>
261<comment>(login to user-mode system)</comment> 340<comment>(login to user-mode system)</comment>
262# <i>ifconfig eth0 192.168.0.1 up</i> 341# <i>ifconfig eth0 192.168.0.1 up</i>
263# <i>ping -c 2 192.168.0.254</i> 342# <i>ping -c 2 192.168.0.254</i>
264PING 192.168.0.254 (192.168.0.254): 56 octets data 343PING 192.168.0.254 (192.168.0.254): 56 octets data
26564 octets from 192.168.0.254: icmp_seq=0 ttl=255 time=0.8 ms 34464 octets from 192.168.0.254: icmp_seq=0 ttl=255 time=0.8 ms
26664 octets from 192.168.0.254: icmp_seq=1 ttl=255 time=0.6 ms 34564 octets from 192.168.0.254: icmp_seq=1 ttl=255 time=0.6 ms
267 346
268--- 192.168.0.254 ping statistics --- 347--- 192.168.0.254 ping statistics ---
2692 packets transmitted, 2 packets received, 0% packet loss 3482 packets transmitted, 2 packets received, 0% packet loss
270round-trip min/avg/max = 0.6/0.7/0.8 ms 349round-trip min/avg/max = 0.6/0.7/0.8 ms
271<i>route add default gw 192.168.0.254</i> 350# <i>route add default gw 192.168.0.254</i>
272<i>netstat -rn</i> 351# <i>netstat -rn</i>
273Kernel IP routing table 352Kernel IP routing table
274Destination Gateway Genmask Flags MSS Window irtt Iface 353Destination Gateway Genmask Flags MSS Window irtt Iface
275192.168.0.0 0.0.0.0 255.255.255.0 U 40 0 0 eth0 354192.168.0.0 0.0.0.0 255.255.255.0 U 40 0 0 eth0
2760.0.0.0 192.168.0.254 0.0.0.0 UG 40 0 0 eth0 3550.0.0.0 192.168.0.254 0.0.0.0 UG 40 0 0 eth0
277<i>scp user@192.168.0.254:/etc/resolv.conf /etc/resolv.conf</i> <comment>(if needed)</comment> 356# <i>scp user@192.168.0.254:/etc/resolv.conf /etc/resolv.conf</i> <comment>(if needed)</comment>
278<i>ping -c 2 www.gentoo.org</i> 357# <i>ping -c 2 www.gentoo.org</i>
279PING www.gentoo.org (207.170.82.202): 56 octets data 358PING www.gentoo.org (207.170.82.202): 56 octets data
28064 octets from 207.170.82.202: icmp_seq=0 ttl=240 time=119.6 ms 35964 octets from 207.170.82.202: icmp_seq=0 ttl=240 time=119.6 ms
28164 octets from 207.170.82.202: icmp_seq=1 ttl=240 time=92.0 ms 36064 octets from 207.170.82.202: icmp_seq=1 ttl=240 time=92.0 ms
282 361
283--- www.gentoo.org ping statistics --- 362--- www.gentoo.org ping statistics ---
2842 packets transmitted, 2 packets received, 0% packet loss 3632 packets transmitted, 2 packets received, 0% packet loss
285round-trip min/avg/max = 92.0/105.8/119.6 ms 364round-trip min/avg/max = 92.0/105.8/119.6 ms
286</pre> 365</pre>
366
287<p> 367<p>
288On the user-mode system we assign the user-mode eth0 interface 368On the user-mode system we assign the user-mode eth0 interface
289the private IP address 192.168.0.1 and bring up the interface. The 369the private IP address 192.168.0.1 and bring up the interface. The
290host has private IP address 192.168.0.254, and we ping it to make sure 370host has private IP address 192.168.0.254, and we ping it to make sure
291that our networking is, indeed, up. The route line adds a default 371that our networking is, indeed, up. The route line adds a default
293<path>/etc/resolv.conf</path> (if necessary), and we ping www.gentoo.org 373<path>/etc/resolv.conf</path> (if necessary), and we ping www.gentoo.org
294to make sure that name resolution (and general access to the internet) 374to make sure that name resolution (and general access to the internet)
295is working from our user-mode system. Now the user-mode system can 375is working from our user-mode system. Now the user-mode system can
296<c>emerge</c> at will! 376<c>emerge</c> at will!
297</p> 377</p>
378
379</body>
380</section>
381<section>
382<title>Using a Virtual Network</title>
383<body>
384
385<p>
386Before you get all too excited, this is not a virtual private network. It is a
387network that is only accessible by the UML instances. The
388<c>usermode-utilities</c> package provides a tool called <c>uml_switch</c> which
389defines the end points of the switch.
390</p>
391
392<pre caption="Activating end points of a UML switch">
393<comment>(If the switch information should stay in the foreground:)</comment>
394$ <i>uml_switch -unix ~/tmp/switch.sock</i>
395
396<comment>(If it should be backgrounded:)</comment>
397$ <i>uml_switch -unix ~/tmp/switch.sock &amp;&gt; ~/tmp/switch.log &amp;</i>
398</pre>
399
400<p>
401To start the UML instances on the switch, run the next command. Your
402(virtual) network interface will be connected to the <c>uml_switch</c> process
403and will be using the given MAC address.
404</p>
405
406<pre caption="Running first UML instance">
407$ <i>linux ubd0=first_rootfs ubd1=first_swapfs eth0=daemon,10:00:01:02:00:00,,~/tmp/switch.sock</i>
408</pre>
409
410<p>
411You can still connect the system to the existing network, or have a second
412process attached to both the virtual one and the existing one:
413</p>
414
415<pre caption="Running second UML instance">
416$ <i>linux ubd0=second_rootfs ubd1=second_swapfs eth0=daemon,10:00:01:02:00:01,,~/tmp/switch.sock \
417 eth1=tuntap,,,192.168.1.43</i>
418</pre>
419
420<p>
421More information about the tuntap setting can be found in the previous section.
422</p>
423
298</body> 424</body>
299</section> 425</section>
300</chapter> 426</chapter>
301
302<chapter> 427<chapter>
303<title>Testing the .iso</title> 428<title>Testing the .iso</title>
304
305<section> 429<section>
306<body> 430<body>
431
307<p> 432<p>
308Perhaps the true ideal of Gentoo Linux testing would be 433Perhaps the true ideal of Gentoo Linux testing would be
309to boot the .iso with user-mode linux and do the complete 434to boot the .iso with user-mode Linux and do the complete
310Gentoo install from within the user-mode linux virtual system. 435Gentoo install from within the user-mode Linux virtual system.
311</p> 436</p>
437
312<p> 438<p>
313Booting the .iso, or actually the initrd from the .iso, is pretty 439Booting the .iso, or actually the initrd from the .iso, is pretty
314straightforward. 440straightforward.
315</p> 441</p>
316<pre> 442
443<pre caption="Booting the ISO">
317# <i>mount -o loop /path/to/build-&lt;TAB&gt;.iso /mnt/loop</i> 444# <i>mount -o loop /path/to/install-&lt;TAB&gt;.iso /mnt/loop</i>
318# <i>cp /mnt/loop/isolinux/rescue.gz .</i> 445# <i>cp /mnt/loop/isolinux/gentoo.igz .</i>
319# <i>linux load_ramdisk=1 prompt_ramdisk=0 ramdisk_size=22000 \</i> 446# <i>linux load_ramdisk=1 prompt_ramdisk=0 ramdisk_size=22000 \</i>
320&gt; <i>initrd=rescue.gz root=/dev/ram0 ubd0=root_fs ubd1=swap_fs \</i> 447&gt; <i>initrd=rescue.gz root=/dev/ram0 ubd0=root_fs ubd1=swap_fs \</i>
321&gt; <i>ubd2=/dev/cdroms/cdrom0 eth0=ethertap,tap0,,192.168.0.254</i> 448&gt; <i>ubd2=/dev/cdroms/cdrom0 eth0=tuntap,,,192.168.0.254</i>
322</pre> 449</pre>
450
451<p>
323<p>Now you can follow the Gentoo install doc essentially verbatim, 452Now you can follow the Gentoo install doc essentially verbatim,
324although you'll need to know that the root filesystem will be 453although you'll need to know that the root filesystem will be
325<path>/dev/ubd/0</path>, the swap "partition" 454<path>/dev/ubd/0</path>, the swap "partition"
326will be <path>/dev/ubd/1</path>, and the CD rom 455will be <path>/dev/ubd/1</path>, and the CD rom
327will be <path>/dev/ubd/2</path>.</p> 456will be <path>/dev/ubd/2</path>.
457</p>
458
328</body> 459</body>
329</section> 460</section>
330</chapter> 461</chapter>
331 462
463<chapter>
464<title>Resources</title>
465<section>
466<body>
467
468<ul>
469 <li>
470 <uri link="http://edeca.net/articles/bridging/index.html">Bridging with
471 UML</uri>
472 </li>
473 <li>
474 <uri link="http://user-mode-linux.sourceforge.net/">UML Homepage</uri>
475 </li>
476 <li>
477 <uri link="http://www.theshore.net/~caker/uml/">Caker's UML Notes</uri>
478 </li>
479 <li>
480 <uri link="http://sourceforge.net/mailarchive/forum.php?forum_id=3647">UML
481 Mailinglist archives</uri>
482 </li>
483</ul>
484
485</body>
486</section>
487</chapter>
332 488
333</guide> 489</guide>

Legend:
Removed from v.1.1  
changed lines
  Added in v.1.31

  ViewVC Help
Powered by ViewVC 1.1.20