From: Nic <nfe...@ta...> - 2006-05-04 09:14:47
|
I'd like to use UML on my laptop for virtualizing my various development projects. Essentially this is about saving disc space. I have lots of webapp (and other tcp daemon) projects that I want a root fs for but I don't want to waste disc space over and over again on the common things. Currently I use unionfs to manage lots of different chroot-able fs. My setup basically does what UML and COW files does. But unionfs/chroot of course offers no virtualization of network stack. It's also just a bit more klunky than I'd like. The trouble is a UML network stack is difficult for this purpose as well. I obviously need to be able to talk to the UMLs from the laptop metal so that I can use the laptop's X installation to run moz and such things against UMLd network services. So a bridge looks likely (anyone think of a creative other way?) I'm quite happy to run a local dhcp server and provide addresses to UMLs, But having a bridge on a laptop is problematic. Laptop network hardware is loaded in a variety of ways: hotplug, kernel, modules, ppp interfaces etc... I'd like to know what other people do, if they do this at all? Anybody have any brilliant ideas to make this kind of ad-hoc environment easier to handle? Nic Ferrier |
From: Blaisorblade <bla...@ya...> - 2006-05-04 19:18:12
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On Thursday 04 May 2006 11:04, Nic wrote: > I'd like to use UML on my laptop for virtualizing my various > development projects. > > Essentially this is about saving disc space. I have lots of webapp > (and other tcp daemon) projects that I want a root fs for but I don't > want to waste disc space over and over again on the common things. > The trouble is a UML network stack is difficult for this purpose as > well. > I obviously need to be able to talk to the UMLs from the laptop > metal so that I can use the laptop's X installation to run moz and > such things against UMLd network services. I.e. you want to talk from the host to the guest via IP, right? You're describing it as if it were an extraordinary thing and this is causing in you more confusion than needed. > So a bridge looks likely (anyone think of a creative other way?) You don't need a bridge at all. Somebody uses a bridge to setup dozens of UMLs with little work and without installing setuid applications (i.e. uml_net in uml-utilities). But that's not needed. Look at http://user-mode-linux.sourceforge.net/networking.html, and choose TUN/TAP with the uml_net helper. You'll also need to assign a MAC to the interface,via: Use eth0=tuntap,,fe:fd:0:0:0:1,$hostip, and choose different MACs (leave the form fe:fd:x:x:x:x). > I'm quite happy to run a local dhcp server and provide addresses to > UMLs, > But having a bridge on a laptop is problematic. Laptop network > hardware is loaded in a variety of ways: hotplug, kernel, modules, ppp > interfaces etc... What are you talking about? What you say does not make sense. hotplug, kernel and modules don't give any load on "laptop network hardware". Especially not hotplug. And running a bridge isn't an heavy (resource-wise) task at all. The only valid interpretation I can form is that bridging together a ppp interface with all the rest is not a good idea, which is true, but on a software bridge you add only the interfaces you choose (I now realize this is non-obvious thinking to an hardware bridge). -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com |
From: Nic <nfe...@ta...> - 2006-05-04 20:04:36
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") Message-ID: <87o...@ni...> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Blaisorblade <bla...@ya...> writes: > You don't need a bridge at all. Somebody uses a bridge to setup dozens of UMLs > with little work and without installing setuid applications (i.e. uml_net in > uml-utilities). But that's not needed. > > Look at http://user-mode-linux.sourceforge.net/networking.html, and choose > TUN/TAP with the uml_net helper. You'll also need to assign a MAC to the > interface,via: > > Use eth0=tuntap,,fe:fd:0:0:0:1,$hostip, and choose different MACs (leave the > form fe:fd:x:x:x:x). Ok. Maybe I'm missing something... but when I start this way I am currently under the impression that I have no way to obtain an automatic IP address. DHCP away from the host machine certainly does not work. Am I wrong? Can I obtain an automatic IP via DHCP or some other means? >> But having a bridge on a laptop is problematic. Laptop network >> hardware is loaded in a variety of ways: hotplug, kernel, modules, ppp >> interfaces etc... > > What are you talking about? What you say does not make sense. hotplug, kernel > and modules don't give any load on "laptop network hardware". Especially not > hotplug. And running a bridge isn't an heavy (resource-wise) task at all. By "loaded" I meant "initialized" and not "heavily resourced". Poor choice of words sorry. Bridges make defining hotplug etc harder than just defining them for stand alone interfaces. Nic |
From: Blaisorblade <bla...@ya...> - 2006-05-04 20:17:22
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On Thursday 04 May 2006 22:03, Nic wrote: > ") > Message-ID: <87o...@ni...> > MIME-Version: 1.0 > Content-Type: text/plain; charset=us-ascii > > Blaisorblade <bla...@ya...> writes: > > You don't need a bridge at all. Somebody uses a bridge to setup dozens of > > UMLs with little work and without installing setuid applications (i.e. > > uml_net in uml-utilities). But that's not needed. > > > > Look at http://user-mode-linux.sourceforge.net/networking.html, and > > choose TUN/TAP with the uml_net helper. You'll also need to assign a MAC > > to the interface,via: > > > > Use eth0=tuntap,,fe:fd:0:0:0:1,$hostip, and choose different MACs (leave > > the form fe:fd:x:x:x:x). > > Ok. Maybe I'm missing something... but when I start this way I am > currently under the impression that I have no way to obtain an > automatic IP address. DHCP away from the host machine certainly does > not work. > Am I wrong? Can I obtain an automatic IP via DHCP or some other means? Let me think... the problem I may think of is that your DHCP server is not listening on tap0. You need to change its configuration and restart it after creating the tap0 interface, i.e. after the UML has booted, and then start dhclient on the UML. Yes, troublesome probably. I don't know if the DHCP server can be made to listen on any interfaces so it will listen also on interfaces started after its boot. Improvements: a) there is dhcp-fwd which forwards DHCP requests from one Ethernet piece to another b) pre-setup a tap0 interface (possibly you'll want to run uml_switch to connect all UMLs to this tap0 device) so that you can run the DHCP server before starting UMLs. c) bridging those two Ethernet interfaces together would work,correct,but can be avoided. d) personally I pass the network params (IP and hostname) to each instance on a cmd line parameter and then inside the UML I parse those params (can be found in /proc/cmdline) and setup networking according to them,instead of using DHCP. > By "loaded" I meant "initialized" and not "heavily resourced". Poor > choice of words sorry. > Bridges make defining hotplug etc harder than just defining them for > stand alone interfaces. Ok, this is much clearer to me, and I understand you. -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com |
From: Nic <nfe...@ta...> - 2006-05-04 21:14:38
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") Message-ID: <87h...@ni...> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Blaisorblade <bla...@ya...> writes: > Let me think... the problem I may think of is that your DHCP server is not > listening on tap0. You need to change its configuration and restart it after > creating the tap0 interface, i.e. after the UML has booted, and then start > dhclient on the UML. Yes, troublesome probably. > > I don't know if the DHCP server can be made to listen on any interfaces so it > will listen also on interfaces started after its boot. > > Improvements: > a) there is dhcp-fwd which forwards DHCP requests from one Ethernet piece to > another Last time I tried a dhcp proxy it didn't work. I was under the impression that there was a problem with DHCP packets as far as the TUN/TAP went... but I may be wrong. > b) pre-setup a tap0 interface (possibly you'll want to run uml_switch to > connect all UMLs to this tap0 device) so that you can run the DHCP server > before starting UMLs. Hmmm... This sounds good. So if I do: tunctl -t mytap then start the dhcp server listening on that device: dhcpd mytap then every UML I want to start looks like this: mykernel ... eth0=tuntap,mytap then inside the VM I'll be able to dhcp to bring up their interfaces? > c) bridging those two Ethernet interfaces together would work,correct,but can > be avoided. I do this for UML hosting. And it does work really nicely. But it requires that the bridge is setup and working and that's not the case on a laptop. > d) personally I pass the network params (IP and hostname) to each instance on > a cmd line parameter and then inside the UML I parse those params (can be > found in /proc/cmdline) and setup networking according to them,instead of > using DHCP. I want autoconfig. Nic |
From: Blaisorblade <bla...@ya...> - 2006-05-04 21:20:30
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On Thursday 04 May 2006 23:07, Nic wrote: > ") > > Improvements: > > a) there is dhcp-fwd which forwards DHCP requests from one Ethernet piece > > to another > > Last time I tried a dhcp proxy it didn't work. I was under the > impression that there was a problem with DHCP packets as far as the > TUN/TAP went... but I may be wrong. TAP interfaces (not tun ones) carry standard Ethernet frames,no more and no less. > > b) pre-setup a tap0 interface (possibly you'll want to run uml_switch to > > connect all UMLs to this tap0 device) so that you can run the DHCP server > > before starting UMLs. > Hmmm... This sounds good. > So if I do: > tunctl -t mytap > then start the dhcp server listening on that device: > dhcpd mytap > then every UML I want to start looks like this: > mykernel ... eth0=tuntap,mytap > then inside the VM I'll be able to dhcp to bring up their interfaces? Yes, this should work, possibly some further config is needed (dunno dhcpd syntax) but this is the idea. _HOWEVER_ you need explicit MAC addresses as otherwise all UMLs will end up with the same MAC: when the interface it's brought up the MAC is set as fe:fd:<the 4 IP bytes>, which works nicely with ifconfig eth0 $ip, but isn't nice with ifconfig eth0 up,since they all get the same IP. -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade ___________________________________ Yahoo! Mail: gratis 1GB per i messaggi e allegati da 10MB http://mail.yahoo.it |
From: Nic <nfe...@ta...> - 2006-05-04 21:44:36
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") Message-ID: <87e...@ni...> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Blaisorblade <bla...@ya...> writes: >> then inside the VM I'll be able to dhcp to bring up their interfaces? > Yes, this should work, possibly some further config is needed (dunno dhcpd > syntax) Ah. Well that's where I have you. > but this is the idea. _HOWEVER_ you need explicit MAC addresses as > otherwise all UMLs will end up with the same MAC: when the interface it's > brought up the MAC is set as fe:fd:<the 4 IP bytes>, which works nicely with > ifconfig eth0 $ip, but isn't nice with ifconfig eth0 up,since they all get > the same IP. I've suggested a recipe for dealing with this before (on this list). You simply add a dhcp-client-identifier statement to the dhclient.conf. dhcpd can arbitrate on address allocation on mac address OR dhcp-client-identifier (or the hardware identifier but you probably don't want to use that). Here's an example; just add this to your /etc/dhclient.conf or /etc/dhclient3.conf: send dhcp-client-identifier "someuml"; and then in your dhcp server's config file write host matches like this: host example_uml_host { option dhcp-client-identifier "someuml"; fixed-address 192.168.1.1; option host-name ... ... } Nic |
From: Nic <nfe...@ta...> - 2006-05-04 23:54:36
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") Message-ID: <878...@ni...> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii The challenge has been sorted. I've got a config that works really well (again, I'm not sure whether to put this on the UML wiki or not... should I?) I use debian so I've got this in my interfaces file: auto umltap iface umltap inet static pre-up tunctl -t $IFACE address 192.168.1.1 netmask 255.255.255.0 up echo "1" > /proc/sys/net/ipv4/ip_forward up /etc/init.d/udhcpd start down /etc/init.d/udhcpd stop down tunctl -d $IFACE Some things to note: - the interface comes up on laptop boot - it auto creates the tuntap device - it turns on forwarding (so the UMLs can see the host) - it starts and stops udhcpd appropriately udhcpd is a good choice for a laptop because it's very light and simple. My udhcpd config allows for a small range of dhcp handled addresses and sets the router as 192.168.1.1 and the DNS as the host's (the laptop's) local DNS server (the laptop runs dnsmasq as a caching DNS server). I then start my UML like this: umlkernel ubd0=... con0=... eth0=tuntap,umltap inside the UML I use dhcp to get an address and bob's your uncle. Or Jeff's your uncle. I'm not sure which. Thanks Blaisorblade for pointing out that a fixed tuntap needn't be in a bridge to bridge to the local machine. I'm still not sure why, when you can forward from the UML to the host, you can't reach other hosts on the host's network; in other words "why do you need a bridge?". Certainly, my UMLs don't seem to be able to do that. Nic |
From: Blaisorblade <bla...@ya...> - 2006-05-05 20:54:04
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On Friday 05 May 2006 01:47, Nic wrote: > ") > Message-ID: <878...@ni...> > MIME-Version: 1.0 > Content-Type: text/plain; charset=us-ascii > > The challenge has been sorted. > > I've got a config that works really well (again, I'm not sure whether > to put this on the UML wiki or not... should I?) Guess yes, there's no reason against that (and this is also true for your previous suggestion about dhcp-client-identifier*). * Btw, can't that be done via sending an hostname (which probably works more easily with clients like dhcpcd, default in Gentoo) and making the server associate IPs with hostnames? Actually you don't need fixed IPs as long as you make your dhcp server be also a DNS server (I remember it can be done, not sure if it required collaboration with bind or if it could be done without bind; dnsmasq contains a DHCP + DNS server to do this, however). > I then start my UML like this: > > umlkernel ubd0=... con0=... eth0=tuntap,umltap > > inside the UML I use dhcp to get an address and > bob's your uncle. Er? What's that? > Or > Jeff's your uncle. I'm not sure which. > Thanks Blaisorblade for pointing out that a fixed tuntap needn't be in > a bridge to bridge to the local machine. > I'm still not sure why, when you can forward from the UML to the host, > you can't reach other hosts on the host's network; in other words "why > do you need a bridge?". Certainly, my UMLs don't seem to be able to do > that. See at the link I pointed out earlier. In short, you either run UML on a private IP on a different subnet than your LAN and MASQUERADE / SNAT it with iptables, or (default) give the UML an IP on the same subnet as your LAN and use proxy ARP - i.e. when a machine in your LAN arps for your UML, let's say 192.168.1.100, your host must answer it has that IP. uml_net does that by default, but with preconfigured tap devices you must do that by hand. -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com |
From: Nic <nfe...@ta...> - 2006-05-05 21:34:46
|
Blaisorblade <bla...@ya...> writes: > * Btw, can't that be done via sending an hostname (which probably works more > easily with clients like dhcpcd, default in Gentoo) and making the server > associate IPs with hostnames? I don't dhcp can _match_ on a sent hostname but it can on a dhcp-client-identifier. All sorts of matching expressions are possible, not just 1:1. > Actually you don't need fixed IPs as long as you make your dhcp server be also > a DNS server (I remember it can be done, not sure if it required > collaboration with bind or if it could be done without bind; dnsmasq contains > a DHCP + DNS server to do this, however). You don't need BIND but you do need the NSd and the DHCPd to be compatible. In my particular system dnsmasq is already being used (for a caching NS) and configuring the listening interface in dnsmasq configures it for both dhcp and dns. Since I don't want my laptop serving dhcp for whatever lan it is connected to this is not an option. If dnsmasq had different config options for the NS and the DHCPD then it would be perfect. >> bob's your uncle. > Er? What's that? Bob's your uncle and Fanny's your aunt. http://www.worldwidewords.org/qa/qa-bob1.htm > See at the link I pointed out earlier. > > In short, you either run UML on a private IP on a different subnet than your > LAN and MASQUERADE / SNAT it with iptables, or (default) give the UML an IP > on the same subnet as your LAN and use proxy ARP - i.e. when a machine in > your LAN arps for your UML, let's say 192.168.1.100, your host must answer it > has that IP. uml_net does that by default, but with preconfigured tap devices > you must do that by hand. Ah yes. That was the down side of doing the preconfigured tap: I don't get to use uml_net to set it up anymore. It's a pity we can't do: uml_switch -tap thetapdevice -daemon and have it all just work. > > -- > Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". > Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) > http://www.user-mode-linux.org/~blaisorblade > Chiacchiera con i tuoi amici in tempo reale! > http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com > > > > --attachment links follows this line-- |
From: Blaisorblade <bla...@ya...> - 2006-05-05 22:11:33
|
On Friday 05 May 2006 23:32, Nic wrote: > Blaisorblade <bla...@ya...> writes: > > * Btw, can't that be done via sending an hostname (which probably works > > more easily with clients like dhcpcd, default in Gentoo) and making the > > server associate IPs with hostnames? > > I don't dhcp can _match_ on a sent hostname but it can on a > dhcp-client-identifier. All sorts of matching expressions are > possible, not just 1:1. > > > Actually you don't need fixed IPs as long as you make your dhcp server be > > also a DNS server (I remember it can be done, not sure if it required > > collaboration with bind or if it could be done without bind; dnsmasq > > contains a DHCP + DNS server to do this, however). > > You don't need BIND but you do need the NSd and the DHCPd to be > compatible. > > In my particular system dnsmasq is already being used (for a caching > NS) and configuring the listening interface in dnsmasq configures it > for both dhcp and dns. Since I don't want my laptop serving dhcp for > whatever lan it is connected to this is not an option. If dnsmasq had > different config options for the NS and the DHCPD then it would be > perfect. I hadn't thought to > >> bob's your uncle. > > > > Er? What's that? > > Bob's your uncle and Fanny's your aunt. > > http://www.worldwidewords.org/qa/qa-bob1.htm > Ah yes. That was the down side of doing the preconfigured tap: I don't > get to use uml_net to set it up anymore. > It's a pity we can't do: > > uml_switch -tap thetapdevice -daemon > > and have it all just work. You mean make uml_switch autoconfigure it? That's an idea... will look at it at some time... -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com |
From: Jason L. <lu...@fa...> - 2006-05-05 19:31:15
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nfe...@ta... said: > My udhcpd config allows for a small range of dhcp handled addresses > and sets the router as 192.168.1.1 and the DNS as the host's (the > laptop's) local DNS server (the laptop runs dnsmasq as a caching DNS > server). If you configure dnsmasq properly, you can probably do away with udhcpd entirely since dnsmasq is both a dhcp server and dns server. Jason |
From: Nic <nfe...@ta...> - 2006-05-05 21:44:40
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") Message-ID: <87l...@ni...> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Jason Lunz <lu...@fa...> writes: > nfe...@ta... said: >> My udhcpd config allows for a small range of dhcp handled addresses >> and sets the router as 192.168.1.1 and the DNS as the host's (the >> laptop's) local DNS server (the laptop runs dnsmasq as a caching DNS >> server). > > If you configure dnsmasq properly, you can probably do away with udhcpd > entirely since dnsmasq is both a dhcp server and dns server. See my answer to blaisorblade. dnsmasq only has one config option for defining the listening address so I can either have my dns only on the private lan and dhcp working or have my dhcp on the public lan with all the problems that my bring. Note: by public I mean the lan the laptop (the host OS) is connected. Nic |
From: Jason L. <lu...@fa...> - 2006-05-06 03:57:31
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nfe...@ta... said: > In my particular system dnsmasq is already being used (for a caching > NS) and configuring the listening interface in dnsmasq configures it > for both dhcp and dns. Since I don't want my laptop serving dhcp for > whatever lan it is connected to this is not an option. If dnsmasq had > different config options for the NS and the DHCPD then it would be > perfect. my dnsmasq manpage says: -2, --no-dhcp-interface=<interface name> Do not provide DHCP on the specified interface, but do provide DNS service. Jason |
From: Nic <nfe...@ta...> - 2006-05-06 08:44:53
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") Message-ID: <87d...@ni...> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Jason Lunz <lu...@fa...> writes: > nfe...@ta... said: >> In my particular system dnsmasq is already being used (for a caching >> NS) and configuring the listening interface in dnsmasq configures it >> for both dhcp and dns. Since I don't want my laptop serving dhcp for >> whatever lan it is connected to this is not an option. If dnsmasq had >> different config options for the NS and the DHCPD then it would be >> perfect. > > my dnsmasq manpage says: > > -2, --no-dhcp-interface=<interface name> > Do not provide DHCP on the specified interface, but do > provide DNS service. Does that mean it does provide DHCP on the other interfaces? I tried some things with dnsmasq last night and I couldn't actually get it to stop listening for DHCP on 0.0.0.0. However, there is another reason for using a separate DHCP server. It's tied to the tap interface being used for the UMLs. When you take the interface down the dhcp server should go down as well. Nic |
From: Blaisorblade <bla...@ya...> - 2006-05-07 18:00:58
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On Saturday 06 May 2006 10:41, Nic wrote: > ") > Message-ID: <87d...@ni...> > MIME-Version: 1.0 > Content-Type: text/plain; charset=us-ascii > > Jason Lunz <lu...@fa...> writes: > > nfe...@ta... said: > >> In my particular system dnsmasq is already being used (for a caching > >> NS) and configuring the listening interface in dnsmasq configures it > >> for both dhcp and dns. Since I don't want my laptop serving dhcp for > >> whatever lan it is connected to this is not an option. If dnsmasq had > >> different config options for the NS and the DHCPD then it would be > >> perfect. > > > > my dnsmasq manpage says: It's then time to upgrade, newer packets are still deemed unstable on Gentoo it seems. > > -2, --no-dhcp-interface=<interface name> > > Do not provide DHCP on the specified interface, but do > > provide DNS service. > > Does that mean it does provide DHCP on the other interfaces? > > I tried some things with dnsmasq last night and I couldn't actually > get it to stop listening for DHCP on 0.0.0.0. That doesn't really matter; from /etc/dnsmasq.conf: # On systems which support it, dnsmasq binds the wildcard address, # even when it is listening on only some interfaces. It then discards # requests that it shouldn't reply to. This has the advantage of # working even when interfaces come and go and change address. If you # want dnsmasq to really bind only the interfaces it is listening on, # uncomment this option. About the only time you may need this is when # running another nameserver on the same machine. #bind-interfaces > However, there is another reason for using a separate DHCP > server. It's tied to the tap interface being used for the UMLs. When > you take the interface down the dhcp server should go down as well. -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com |
From: Nic <nfe...@ta...> - 2006-05-07 18:24:58
|
Nic said: >> I tried some things with dnsmasq last night and I couldn't actually >> get it to stop listening for DHCP on 0.0.0.0. Blaisorblade <bla...@ya...> responded: > > That doesn't really matter; from /etc/dnsmasq.conf: > > # On systems which support it, dnsmasq binds the wildcard address, > # even when it is listening on only some interfaces. It then discards > # requests that it shouldn't reply to. This has the advantage of > # working even when interfaces come and go and change address. If you > # want dnsmasq to really bind only the interfaces it is listening on, > # uncomment this option. About the only time you may need this is when > # running another nameserver on the same machine. > #bind-interfaces And of course I tried that. I'm not a total fool (an almost total fool, I admit). I had that option turned on and still it listened to 0.0.0.0 for DHCP (it worked for DNS though). Also, it did not throw away the connection for DHCP, I tried send DHCP requests to the laptop from another machine on the LAN; the laptop did not throw them away. Clearly, dnsmasq doesn't always work as advertised. I do use debian/sid though so maybe a more stable version would work. Nic |
From: Anselm L. <an...@st...> - 2006-05-07 22:37:11
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Nic wrote: > Clearly, dnsmasq doesn't always work as advertised. > > I do use debian/sid though so maybe a more stable version would work. Did you log a bug against the dnsmasq in Debian Sid? Anselm -- Anselm Lingnau, Frankfurt, Germany ..................... an...@st... The secret of being miserable is to have leisure to bother about whether you are happy or not. The cure for it is occupation. -- George Bernard Shaw |
From: Nic J. F. <nfe...@ta...> - 2006-05-30 22:46:55
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") Message-ID: <87h...@ni...> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sometime ago we had this conversation about how to do dynamic creation of UMLs, particularly for laptop development environments. Blaisorblade <bla...@ya...> writes: > b) pre-setup a tap0 interface (possibly you'll want to run uml_switch to > connect all UMLs to this tap0 device) so that you can run the DHCP server > before starting UMLs. Can you explain this a bit more? I'll explain why. My laptop uml setup works really well... I can create UMLs on the fly with one command. But I can't start more than one at once and get a network device and I want to be able to. Here's (roughly) my current bootscript: umlkernel \ ubd0=localcow,/someplace/umlfs \ ubd1=/someplace/swap \ eth0=tuntap,umltap umltap is a tuntap which is preconfigured at host OS boot time. I have a dhcp server listening on the tuntap interface. If I try to boot two UMLs simultaneously then one of them doesn't get a network. So, first question: do I need a new tun device for every UML I start? If I create a new tuntap device and pass it to the UML line, thus: tunctl -t umltap2 ifconfig umltap2 192.168.1.4 up route add -host 192.168.1.4 dev umltap2 bash -c 'echo 1 > /proc/sys/net/ipv4/conf/umltap2/proxy_arp' arp -Ds 192.168.1.4 umltap pub I can ping from the host to the new tuntap. I can bring up the eth in the new uml manually and ping to the host OS but DHCP allocation inside the UML does not work. My second question is: can uml_switch help me make tuntap's on the fly and connect them all together? Nic Ferrier |
From: Nic J. F. <nfe...@ta...> - 2006-05-31 00:14:14
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") Message-ID: <87e...@ni...> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Nic James Ferrier <nfe...@ta...> writes: > My second question is: can uml_switch help me make tuntap's on the fly > and connect them all together? Never mind. The crappy man page I was reading was nothing to: http://user-mode-linux.sourceforge.net/UserModeLinux-HOWTO-6.html#ss6.9 which has a full explanation of how to use the uml_switch. Works for me! If I can create an account I'll document my setup on the wiki. -- Nic Ferrier http://www.tapsellferrier.co.uk for all your tapsell ferrier needs |
From: Anthony B. <Ant...@or...> - 2006-05-31 05:11:24
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-----Original Message----- > Nic James Ferrier <nfe...@ta...> writes: > >> My second question is: can uml_switch help me make tuntap's on the fly >> and connect them all together? > > > Never mind. > > The crappy man page I was reading was nothing to: > > http://user-mode-linux.sourceforge.net/UserModeLinux-HOWTO-6.html#ss6.9 > > which has a full explanation of how to use the uml_switch. Works for > me! > > If I can create an account I'll document my setup on the wiki. You shouldn't need an account. The wiki is located at: http://uml.harlowhill.com/ and allows guest users to modify pages. In fact, it would be nice if you could link your instructions to: http://uml.harlowhill.com/index.php/UMLNetworking As you can see, a couple forms of networking are covered and could probably use some updating. However, UML switch isn't. If nothing else, this should probably point users back to the link you found... Tony |