lsc@luke.xen.prgmr.com
2008-Feb-08 14:59 UTC
Re: [Xen-users] virtual machines, DHCP, and ssh?
On Fri, Feb 08, 2008 at 05:36:15PM -0500, Tom Horsley wrote:> I''d love to setup DHCP on the Xen host and just allocate > whatever IP is available to whatever new VM was just booted, > but with different VMs reusing the same IP addrs, everyone''s > ssh clients will constantly be honking at them about the > host keys changing.you should access your servers by name, not by IP, and your servers, when they come up, should dynamically setup A and PTR records. You can do this with rc scripts within your DomU and nsupdate, but the DHCP folks have alrealdy set you up, I believe you want to look up the ddns-update* directives in dhcpd.conf. It''s been a while since I''ve messed with it, but here is a guide that looks pretty good: http://www.cameratim.com/computing/linux/using-bind-as-a-local-dns-server _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Just curious if anyone knows if there is a way to get ssh host keys set by DHCP? We''ve got a limited number of IP addrs for VMs (because there are a limited number of VMs that can boot at the same time before we run out of memory on the host :-). But we have a gazillion or so VMs for testing different linux distributions and wot-not. I''d love to setup DHCP on the Xen host and just allocate whatever IP is available to whatever new VM was just booted, but with different VMs reusing the same IP addrs, everyone''s ssh clients will constantly be honking at them about the host keys changing. Anyone encountered this and have a nifty work-around? Is my best bet to invent a new init script that runs before sshd is started to check what IP I have and copy the appropriate ssh host keys into /etc/ssh? (Then try and remember to get that init script installed on all the VMs :-). _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Fri, 8 Feb 2008 09:59:26 -0500 lsc@luke.xen.prgmr.com wrote:> you should access your servers by name, not by IPHmmm... I thought the fact that I see both name and IP stored in the ~/.ssh/known_hosts file meant that ssh was keeping track of both and would honk if either results in a conflict. Maybe that isn''t the way it works? _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users