Difference between revisions of "Xen customer information"

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(General: Clarification of data transfer limits)
(General: Only non-local traffic is counted)
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====Are my bandwidth limits outbound or inbound or both?====
 
====Are my bandwidth limits outbound or inbound or both?====
 
Currently since there is an excess of inbound bandwidth, you can have twice as much  inbound as outbound.  e.g. if your plan allows 50GB data transfer then this corresponds to 50GB out (people downloading from your domain) and 100GB in (people uploading to your domain).  Excess data transfer is still charged the same.
 
Currently since there is an excess of inbound bandwidth, you can have twice as much  inbound as outbound.  e.g. if your plan allows 50GB data transfer then this corresponds to 50GB out (people downloading from your domain) and 100GB in (people uploading to your domain).  Excess data transfer is still charged the same.
 +
 +
====Does my local traffic get counted towards my allowance?====
 +
No.  Only traffic destined for or coming from outside of <tt>212.13.198.64/27</tt> will be counted.  This is great incentive for you to make use of the [[Xen customer information#Shared_resources|shared resources]] on offer such as an APT cache and recursive DNS.
  
 
====Do I need to synchronise my clock like I would on a normal server?====
 
====Do I need to synchronise my clock like I would on a normal server?====

Revision as of 14:50, 22 December 2005

This article provides some useful information for customers of Strugglers Xen virtual machine hosting.

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.

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

Are my bandwidth limits outbound or inbound or both?

Currently since there is an excess of inbound bandwidth, you can have twice as much inbound as outbound. e.g. if your plan allows 50GB data transfer then this corresponds to 50GB out (people downloading from your domain) and 100GB in (people uploading to your domain). Excess data transfer is still charged the same.

Does my local traffic get counted towards my allowance?

No. Only traffic destined for or coming from outside of 212.13.198.64/27 will be counted. This is great incentive for you to make use of the shared resources on offer such as an APT cache and recursive DNS.

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.