Ubuntu Enterprise Cloud (private) vs DRBD, Heartbeat, KVM

[Matthew Lengenfelder]

I'm thinking about setting up 2 Ubuntu servers, then using DRBD, heartbeat, and iscsi. Those 2 machines will basically be redundant storage for virtual machines, if one goes down, the other one will keep ticking and all the virtual machines stored on both of them will continue to be accessible by the other machines running the virtual machines. Then I'll have 2 or more other machines that are running KVM virtual machines and those virtual machines (web servers, an email server, some windows Terminal Servers, etc). Basicly the idea is that if one of the KVM servers go down, We'll have either a backup server that we can use to replace the downed server and get back up and running in moments (because they're running on iscsi/remote storage, if one machine goes down, it's as easy as telling a different machine to start the virtual machines that the downed machine was running, or perhaps even have some sort of heartbeat/pacemaker type script that manages that automatically.

I think this is a perty decent plan, and some of the virtual machines can be load balanced and whatnot depending upon the type of virtual machine (we won't be load balancing our windows terminal servers, but we could do that with the linux web servers... etc)

I ran across some articles on Ubuntu Enterprise Cloud but they don't really talk about what a cloud really gives you. It appears that there is one master cloud computer that basicly controls the cloud, if it goes down does the whole cloud go down... or perhaps a bigger concern is how is the data on each individual cloud node being backed up. If I'm running a Windows terminal server on one node and that node goes down, does the terminal server continue to run? I'm not sure how a cloud would work without some sort of remote storage solution, unless everything is being replicated to multiple machines, but if that's the case and I have one node that has 1TB of HDD space and another node that has 8TB of HDD space it obviously can't replicate all of the data from the 8TB of storage to the 1TB of storage... do all of the nodes need to be running on identical hardware? If so what happens a year after it's built and 16 core(or whatever) cpu's are out and 4TB HDD's are out and you want to start using the new hardware, do you have to build a second cloud with the better hardware and basically scrap the first? I guess I just have a lot of questions and not much experience about private clouds and why you would choose that over a DRBD/Heartbeat/KVM solution... anyone here played with them or have some good links where some of my questions might get answers, I haven't been having much luck finding them myself.

Matt L.

[Matthew Lengenfelder]

After reading some more, I found one post that someone pointed out that you have to stop looking at it and talking about the "cloud" and start talking about the underlying technology that makes the cloud. So, I found out that Ubuntu Enterprise Cloud uses Eucalyptus, I'll have to read some more about it and I'll probably be able to figure it out.

[Jonathan Ziemann]

Here is some documentation on what you are looking at setting up:

https://help.ubuntu.com/community/UEC

Here is the setup guide for the advanced configuration:

https://help.ubuntu.com/community/UEC/PackageInstallSeparate

Jona

[Robert Hart]

I would suggest that if you have a couple of spare desktops then you can
play and try things out. You probably cannot do an end to end mock-up
but you could at least test some of the bits you are unsure about.

Also if you get it all worked out, I would love to hear you do a talk
about it.

Robert

[Jonathan Ziemann]

I totally agree with Robert.  Test sites are always a good starting point, so you know how to convert your existing infrastructure.  It would also be a good idea to create a site map of what you want to end up with, and what steps you need to take to get there.  You might find this difficult without a project plan in place.

[Matthew Lengenfelder]

So Ubuntu Enterprise Cloud uses Eucalyptus. Eucalyptus is free, but if you want iscsi and other features that I want... it's not free. So I think I'll try out the DRBD/KVM/heartbeat route. I'll let you know if I manage to get it up and running.

Matt L.

[Brent]

I don't know much about Ubuntu Enterprise Cloud or Eucalyptus, but if
you need iSCSI target support there are two production worthy projects
available for implementing it. SCST (http://scst.sourceforge.net/)
and IET - iscsi-target (http://iscsitarget.sourceforge.net/). I think
iscsi-target is bundled with centos and scst is supposedly to become
part of the Linux base driver distribution soon. I have personally
used IET/iscsi-target and found it to be stable. I am less familiar
with SCST as it was built after I did my first iSCSI implementation,
but I do monitor both mail lists and SCST seems to have the advantage
(http://scst.sourceforge.net/comparison.html).

[Jonathan Ziemann]

FreeNas has support for iSCSI and NFS.  I have personally used it and it works really well.  It has a very small footprint, good online support, and has many configuration options.  I believe that you can run it off of a flash drive.   It is in process of moving from FreeBSD to Debian. http://freenas.org/freenas

Here is some additional info:

FreeNAS is an embedded open source NAS (Network-Attached Storage) distribution based on FreeBSD, supporting the following protocols: CIFS (samba), FTP, NFS, TFTP, AFP, RSYNC, Unison, iSCSI (initiator and target) and UPnP.

It supports Software RAID (0,1,5), ZFS, disk encryption, S.M.A.R.T/email monitoring with a WEB configuration interface (fromm0n0wall).

FreeNAS can be installed on Compact Flash/USB key, hard drive or booted from LiveCD.