Xen customer information
This article provides some useful information for customers of Strugglers Xen virtual machine hosting.
Contents
Network settings
If hosted on curacao your settings should be as follows:
Address: 212.13.198.x
Gateway: 212.13.198.65
Netmask: 255.255.255.224
Nameservers
You can run your own nameserver, but a resolver is supplied. See Shared resources.
DNS
There is a recursive DNS server on 212.13.198.71 and/or 2001:ba8:0:1f1:a800:ff:fe13:5ca4. If you aren't running your own nameserver then you can use this IP in your /etc/resolv.conf. If you are, then you can use this IP as a forwarder.
apt cache
See the Debian-specific section of the FAQ, below.
SpamAssassin
There is a SpamAssassin spamd on 212.13.198.71 which you can connect to with spamc or other spamd clients. You will not be able to influence the settings of this spamd, but you may find it useful as running your own spamd tends to eat up a lot of RAM.
Frequently asked questions
General
Do I need to synchronise my clock like I would on a normal server?
No, Xen gets the system time from the host which is already NTP-synced. Running your own ntpd (for example) will work but is unnecessary.
Is 64MiB of RAM really enough to do anything useful?
Sure. It's not a great deal, but it's not like trying to run an entire machine in 64MiB either. A Xen user domain kernel is very stripped-down and you probably don't need to run many daemons.
Here's some top output from one of my own user domains which at the time had 128MiB RAM. It's the one hosting this web site, and it runs Apache 2 with PHP, Exim 4 and BIND 9:
top - 05:28:03 up 12 days, 14:07, 3 users, load average: 0.01, 0.01, 0.00 Tasks: 57 total, 2 running, 52 sleeping, 3 stopped, 0 zombie Cpu(s): 0.0% us, 0.0% sy, 0.0% ni, 100.0% id, 0.0% wa, 0.0% hi, 0.0% si Mem: 126388k total, 122148k used, 4240k free, 27288k buffers Swap: 262136k total, 4k used, 262132k free, 62016k cached
Note that a large amount of memory is being used for buffer and disk cache anyway.
If you find you're running out then you can purchase more RAM and it will be quickly provisioned.
IPv6! How do I get that working?
It probably will "just work". Bring up a network interface that is configured to listen to router advertisements and it should get an IPv6 address based on the MAC address of the interface. On linux domains that happens automatically when eth0 comes up.
Some hosts to talk to to see if it works:
$ ping6 noc.sixxs.net PING noc.sixxs.net(noc.sixxs.net) 56 data bytes 64 bytes from noc.sixxs.net: icmp_seq=1 ttl=45 time=308 ms 64 bytes from noc.sixxs.net: icmp_seq=2 ttl=45 time=305 ms 64 bytes from noc.sixxs.net: icmp_seq=3 ttl=45 time=306 ms 64 bytes from noc.sixxs.net: icmp_seq=4 ttl=45 time=307 ms 64 bytes from noc.sixxs.net: icmp_seq=5 ttl=46 time=305 ms --- noc.sixxs.net ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4040ms rtt min/avg/max/mdev = 305.660/306.595/308.063/0.894 ms $ traceroute6 mx1.blitzed.org traceroute to mx1.blitzed.org (2001:1b50:1::2) from 2001:ba8:0:1f1:a800:ff:fe0a:dd6a, 30 hops max, 16 byte packets 1 2001:ba8:0:1f1::1 (2001:ba8:0:1f1::1) 0.553 ms 0.402 ms 0.419 ms 2 netservices-uk6x.ipv6.btexact.com (2001:7f8:2:1::11) 1.236 ms * 1.294 ms 3 2001:7f8:3::cb9:0:1 (2001:7f8:3::cb9:0:1) 239.865 ms 240.162 ms 359.628 ms 4 so-6-0-0.lon11.ip6.tiscali.net (2001:668:0:2::521) 277.956 ms 242.203 ms 242.088 ms 5 so-1-0-0.lon22.ip6.tiscali.net (2001:668:0:2::450) 242.058 ms 241.987 ms 241.816 ms 6 so-2-0-0.par22.ip6.tiscali.net (2001:668:0:2::b0) 249.595 ms 256.884 ms 248.958 ms 7 so-2-0-0.par30.ip6.tiscali.net (2001:668:0:2::a0) 249.363 ms 249.146 ms 249.324 ms 8 so-1-0-0.par31.ip6.tiscali.net (2001:668:0:2::4c0) 249.207 ms 249.379 ms 249.467 ms 9 so-1-0-2.fra10.ip6.tiscali.net (2001:668:0:2::3a1) 257.856 ms 326.85 ms 257.824 ms 10 so-1-0-0.fra20.ip6.tiscali.net (2001:668:0:2::3f1) 355.383 ms 411.456 ms 257.812 ms 11 so-0-0-0.bsl10.ip6.tiscali.net (2001:668:0:2::261) 262.815 ms 262.686 ms 262.569 ms 12 genotec-gw.ip6.tiscali.net (2001:668:0:3::5000:2) 24.306 ms 24.058 ms 24. 197 ms 13 gic-rou-01-all-pos4-0.as16215.net (2001:1b50::1565) 23.847 ms 24.346 ms 24.15 ms 14 2001:1b50:1::2 (2001:1b50:1::2) 24.501 ms 24.077 ms 24.12 ms
Can/should I run my own firewall?
You can, and you probably should. Whatever you normally use should work. iptables works fine for Linux, for example.
General Linux
Can I compile my own kernel?
Unfortunately at the moment the user domain's kernel must be stored outside the domain itself, in dom0. A facility for user domains to provide their own kernel may be provided in a later version of Xen but until then, if you feel you need a custom kernel, just let me know.
Bear in mind that Xen itself is currently a patch to the Linux kernel, so the range of kernels I can run is rather limited and adding additional patches can be problematic.
You may be interested in the config file for my user domain kernel.
Debian-specific
What should I put in my /etc/apt/sources.list file?
I've set up a local apt-proxy so that packages only need to be downloaded once. Assuming you're using Debian Sarge (stable) then you will want something like:
deb http://admin.curacao.strugglers.net:9999/debian/ sarge main deb-src http://admin.curacao.strugglers.net:9999/debian/ sarge main deb http://admin.curacao.strugglers.net:9999/security sarge/updates main
You can replace sarge with etch for testing.