X-Original-To: alpine-devel@lists.alpinelinux.org Delivered-To: alpine-devel@mail.alpinelinux.org Received: from mail-qc0-f176.google.com (mail-qc0-f176.google.com [209.85.216.176]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mail.alpinelinux.org (Postfix) with ESMTPS id 1D1FFDC008C for ; Sun, 20 Jan 2013 16:38:07 +0000 (UTC) Received: by mail-qc0-f176.google.com with SMTP id n41so3351079qco.35 for ; Sun, 20 Jan 2013 08:38:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; bh=BG4WZe9w+qhzXhU3bP7t4cxkT0HUd4rRe6D3q2WXEJA=; b=Gbk1wJkvlEzIv1egq6wuoT2KxxZyf64M3bOBRNf78XUsHuSkxggJV9vMee5LylzUCj yl9tuuVKyLUWsLZR/yQLcGc4iUIkSvfoTl6k3ufr5sbdP/JZEGThGh4Q8nK3JCkZ5k+4 5cEQqAZoffdGvWEeJL+JtW++qUYD9rXm7bHwpr3E+2Js6YbWEHk7wbyqqqYoNx+769kK viB1P/DsTULJ+IgamVGXtzh6J282SNryYq/RQRJhFdEynwYEmIxEiiaj0CdBeT0cpEyP +XKyZrHeTFC54OKXwosNtZuslglMWOZ0tJugbiC+TnmzNmNZ6Nawhpg04wzWNiHVtkMU KXDg== X-Mailinglist: alpine-devel Precedence: list List-Id: Alpine Development List-Unsubscribe: List-Post: List-Help: List-Subscribe: MIME-Version: 1.0 X-Received: by 10.229.194.9 with SMTP id dw9mr3958116qcb.6.1358699887308; Sun, 20 Jan 2013 08:38:07 -0800 (PST) Received: by 10.49.119.228 with HTTP; Sun, 20 Jan 2013 08:38:06 -0800 (PST) In-Reply-To: <50F92E77.4050406@citrix.com> References: <50F92E77.4050406@citrix.com> Date: Sun, 20 Jan 2013 18:38:06 +0200 Message-ID: Subject: Re: [alpine-devel] Use cases of Alpine Linux and Xen From: Florian Heigl To: =?ISO-8859-1?Q?Roger_Pau_Monn=E9?= Cc: Alpine Development Content-Type: multipart/alternative; boundary=005045013e0023ae4004d3baf8d7 --005045013e0023ae4004d3baf8d7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi, Time goes just too fast. Better I get started on an reply. * Why did you choose Alpine Linux as your Dom0? 1) size: It has a lean codebase, a very vanilla and modern kernel, which makes it realistic to apply changes without risk of introducing new issues. Examples that are relevant for me were: OpenVswitch. Another example is Flashcache (for example Flashcache is still in Catchup on resilience features like ssd loss handling. There might be a nice and tiny patch that does all I want. It is thus really important to be able to add some patches to flashcache with smaller means than "yum -y upgrade" On a distro that is mostly outdated plus important patches plus backports, this can be much, much harder, resulting in more frustration on my side, not to mention the difference in "OPEX" for doing those changes. Another example would be taming the monster named ixgbe + vnics. This or NPIV are highly relevant functions for virtualization if you want abstraction "done right". They're practically impossible to use on major distros though. 2) Unique features. I found out about Alpine not as a Xen distro - I found it because I was looking for something that goes beyond the commonly available networking options, be it very old (bridging) or newer (openvswitch+gre as the current practice). I want to be able to run a really virtualized infrastructure and after months found out there is only one distro that offers DMVPN. Next I found out that distro is made with a very network-engineeric mindset, being able to run from RAM and actually designed to make that easy. I've in the past made CentOS and later OracleVM (google: xen black magic) run "almost stateless" from a readonly root with a lot of ram-backed tmpfs, and it was as far as you can take those RHEL-based distros. You'll also be just as far from any idea of vendor support with such a setup. Just imagine my surprise when I found Alpine comes with this designed in and commonly run in a ram-backed mode. Why is that so important? Because, let's be honest, dom0 is not important. Important are those VMs I'm running for other people and that pesky dom0 should be incredibly indestructible and immortal so it can always serve them. No matter if all my disks failed, the networking died or the sun is sending nasty rays upsetting my ECC memory (Yes, Alpine helps me with that too because it has a current kernel and so it can read the MCE data passed from Xen) 3. Advantages over other dom0 distros the distros are split in three groups currently: - Distros not designed for embedded-ish use. They can be used in the sense of a dom0, but they are trying to suit everyone. Yes, you can strip down all of them, but thats something different than someone checking their being usable to some task in the first place. Virtualization, in their context, is running a VM on the dev's laptop and be amazed that it works. Thus they'll also focus on libvirt and virt-manager. Worse, for trying to build a stable platform is their tendency towards desktop parts like dbus, udev (yeah I said it) and upstart/systemd (and I said it again). Debian Ubuntu RHEL* The first 3 usually don't have a fully working Xen, or it's outdated, or it's not supported right now[tm]. SUSE (ok, they get many points for being on the edge of things most of the time) - Distros that are hypervisor-optimized, but except to be some other system's worker node. Oracle VM Oracle VM has been my fav platform and I'm certified to build or break it, but let's be honest - Oracle VM is for running Oracle VMs. I don't do that all that much. XCP XenServer (SmartOS, too, and I love Zones so I'll live with it using KVM instead of Xen) I've made a point to strip / rebuild Oracle VM so that it runs on it's own. That was successful and I've used that setup for a few years. What turned me off (for my case) was that I needed a newer Xen + Kernel setup to bring in all those goodies. I'll never again use any of those distros in their "normal" mode which is all a messed up python-tracebacks and U-U-I-D mess. - Distros I can't afford: SUSE Carrier Grade Linux (Here I could also run Veritas Cluster / FS which would mean a stable storage subsystem. But that I can't afford either) Montavista " " " (Ok, that's using KVM but I'd suck it up if I had that on all my servers) - Distros that don't exist as far as I'm concerned: Symatec's Xen Datacenter platform xVM tl;dr / quotable part :) Alpine does not try to set a direction for VM management, nor on anything else. This means it's possible to build a well-integrated robust platform. Due to the small footprint it's possible to easily adjust it to my needs, add new features and verify the whole platform is working as intended. I quite miss something like kickstart, but to be honest I can now simply install a host using "dd" and adjusting the IP. In other distros you need powerful installation frameworks to tame a complexity Alpine simply avoids the having used the "simple stick" on time. Greetings Florian In case anyone wonders if I'm simply unable to stick with a distro - no :) I'm using Xen very long, felt the need for some embedded distro very early, rolled my own (XenDistro) and used that for 5 years-ish. That brought along a curiosity and so I simply tested every new thing that people came up with= . At work, we used XenServer and I've supported that platform since the 3.x days, creating the base my dislike of anything that has a UUID in it - but I pretty much like the 6.x series so far. 2013/1/18 Roger Pau Monn=E9 > Hello, > > I'm planning to write a blog post about Alpine Linux and it's Xen > support on http://blog.xen.org if that's fine with everyone. Since > Alpine Linux is not as widely known as let's say Debian or Fedora I > would like to get some feedback from users that are actually using > Alpine Linux and Xen. Mainly I would be interested in the following point= s: > > * Why did you choose Alpine Linux as your Dom0? > * What do you think are the benefits of using an Alpine Linux Dom0 over > other distributions? > > If you would also like to contribute with specific use-cases or examples > where Alpine Linux Dom0 is a good choice I would also welcome them very > much. > > Thanks, Roger. > > > --- > Unsubscribe: alpine-devel+unsubscribe@lists.alpinelinux.org > Help: alpine-devel+help@lists.alpinelinux.org > --- > > --=20 the purpose of libvirt is to provide an abstraction layer hiding all xen features added since 2006 until they were finally understood and copied by the kvm devs. --005045013e0023ae4004d3baf8d7 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi,
Time goes just too fast.=A0
Better I get started on an re= ply.

* Why did you choose Alpine Linux as your Dom= 0?
1) size: It has a lean codebase, a very vanilla and modern= kernel, which makes it realistic to apply changes without risk of introduc= ing new issues. Examples that are relevant for me were: OpenVswitch. Anothe= r example is Flashcache (for example Flashcache is still in Catchup on resi= lience features like ssd loss handling. There might be a nice and tiny patc= h that does all I want. It is thus really important to be able to add some = patches to flashcache with smaller means than "yum -y upgrade"
On a distro that is mostly outdated plus important patches plus backpo= rts, this can be much, much harder, resulting in more frustration on my sid= e, not to mention the difference in "OPEX" for doing those change= s.
Another example would be taming the monster named ixgbe + vnics.
=
This or NPIV are highly relevant functions for virtualization if you w= ant abstraction "done right". They're practically impossible = to use on major distros though.

2) Unique features.
I found out about Alpine = not as a Xen distro - I found it because I was looking for something that g= oes beyond the commonly available networking options, be it very old (bridg= ing) or newer (openvswitch+gre as the current practice).
I want to be able to run a really virtualized infrastructure and after= months found out there is only one distro that offers DMVPN.
Nex= t I found out that distro is made with a very network-engineeric mindset, b= eing able to run from RAM and actually designed to make that easy. I've= in the past made CentOS and later OracleVM (google: xen black magic) run &= quot;almost stateless" from a readonly root with a lot of ram-backed t= mpfs, and it was as far as you can take those RHEL-based distros. You'l= l also be just as far from any idea of vendor support with such a setup.
Just imagine my surprise when I found Alpine comes with this designed = in and commonly run in a ram-backed mode.
Why is that so importan= t?
Because, let's be honest, dom0 is not important. Important= are those VMs I'm running for other people and that pesky dom0 should = be incredibly indestructible and immortal so it can always serve them. No m= atter if all my disks failed, the networking died or the sun is sending nas= ty rays upsetting my ECC memory (Yes, Alpine helps me with that too because= it has a current kernel and so it can read the MCE data passed from Xen)

3. Advantages over other dom0 distros
the dis= tros are split in three groups currently:
- Distros not designed = for embedded-ish use. They can be used in the sense of a dom0, but they are= trying to suit everyone.
Yes, you can strip down all of them, but thats something different tha= n someone checking their being usable to some task in the first place. Virt= ualization, in their context, is running a VM on the dev's laptop and b= e amazed that it works. Thus they'll also focus on libvirt and virt-man= ager. Worse, for trying to build a stable platform is their tendency toward= s desktop parts like dbus, udev (yeah I said it) and upstart/systemd (and I= said it again).

Debian
Ubuntu
RHEL*
The f= irst 3 usually don't have a fully working Xen, or it's outdated, or= it's not supported right now[tm].

SUSE (ok, t= hey get many points for being on the edge of things most of the time)

- Distros that are hypervisor-optimized, but except to = be some other system's worker node.
Oracle VM
Oracl= e VM has been my fav platform and I'm certified to build or break it, b= ut let's be honest - Oracle VM is for running Oracle VMs. I don't d= o that all that much.
XCP
XenServer
(SmartOS, too, and I love Zones so I= 'll live with it using KVM instead of Xen)

I&#= 39;ve made a point to strip / rebuild Oracle VM so that it runs on it's= own.
That was successful and I've used that setup for a few years. What= turned me off (for my case) was that I needed a newer Xen + Kernel setup t= o bring in all those goodies.
I'll never again use any of tho= se distros in their "normal" mode which is all a messed up python= -tracebacks and U-U-I-D mess.

- Distros I can't afford:
SUSE Carrier Gr= ade Linux (Here I could also run Veritas Cluster / FS which would mean a st= able storage subsystem. But that I can't afford either)
Monta= vista " " " (Ok, that's using KVM but I'd suck it up= if I had that on all my servers)

- Distros that don't exist as far as I'm concer= ned:
Symatec's Xen Datacenter platform
xVM



tl;dr / quotable part :)
Alpine does not try to set a direction for VM management, nor on anyth= ing else. This means it's possible to build a well-integrated robust pl= atform.
Due to the small footprint it's possible to easily ad= just it to my needs, add new features and verify the whole platform is work= ing as intended.
I quite miss something like kickstart, but to be honest I can now simp= ly install a host using "dd" and adjusting the IP. In other distr= os you need powerful installation frameworks to tame a complexity Alpine si= mply avoids the having used the "simple stick" on time.


Greetings
Florian
In case anyone wonders if I'm simply unable to stick = with a distro - no :)
I'm using Xen very long, felt the need = for some embedded distro very early, rolled my own (XenDistro) and used tha= t for 5 years-ish. That brought along a curiosity and so I simply tested ev= ery new thing that people came up with.
At work, we used XenServer and I've supported that platform = since the 3.x days, creating the base my dislike of anything that has a UUI= D in it - but I pretty much like the 6.x series so far.



2013/1/18 Roger Pau Monn= =E9 <roger.pau@citrix.com>
Hello,

I'm planning to write a blog post about Alpine Linux and it's Xen support on http://blog.xe= n.org if that's fine with everyone. Since
Alpine Linux is not as widely known as let's say Debian or Fedora I
would like to get some feedback from users that are actually using
Alpine Linux and Xen. Mainly I would be interested in the following points:=

* Why did you choose Alpine Linux as your Dom0?
* What do you think are the benefits of using an Alpine Linux Dom0 over
other distributions?

If you would also like to contribute with specific use-cases or examples where Alpine Linux Dom0 is a good choice I would also welcome them very
much.

Thanks, Roger.


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--
the purpose = of libvirt is to provide an abstraction layer hiding all xen features added= since 2006 until they were finally understood and copied by the kvm devs.

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