uclibc

uclibc

[Markus Volk]

Hello,

i´m trying to build an image using the poky master branch and i´m stuck right at the beginning with this error message:

NOTE: Resolving any missing task queue dependencies
ERROR: Nothing RPROVIDES 'nativesdk-glibc' (but /home/flk/yocto/poky/meta/recipes-core/meta/uninative-tarball.bb RDEPENDS on or otherwise requires it)
ERROR: nativesdk-glibc was skipped: PREFERRED_PROVIDER_virtual/nativesdk-x86_64-oesdk-linux-libc-for-gcc set to nativesdk-uclibc, not nativesdk-glibc
NOTE: Runtime target 'nativesdk-glibc' is unbuildable, removing...
Missing or unbuildable dependency chain was: ['nativesdk-glibc']
ERROR: Required build target 'neutrino-image' has no buildable providers.
Missing or unbuildable dependency chain was: ['neutrino-image', 'uninative-tarball', 'nativesdk-glibc']

Summary: There was 1 WARNING message shown.
Summary: There were 2 ERROR messages shown, returning a non-zero exit code.

Building the image with TCLIBC = „glibc“ just works fine. i´m also capable to build an uclibc image with poky using the jethro branch without errors

any ideas,

Markus Volk

Re: uclibc

[Khem Raj]

Please try this patch here

https://github.com/kraj/openembedded-core/commit/3345a12ed0dbf71b517d2560be73d5da52491b8f

This is in my pending queues that will be submitted soon.

On Sat, Dec 19, 2015 at 1:18 AM, Markus Volk <f_l_k@t-online.de> wrote:
> Hello,
>
> i´m trying to build an image using the poky master branch and i´m stuck right at the beginning with this error message:
>
> NOTE: Resolving any missing task queue dependencies
> ERROR: Nothing RPROVIDES 'nativesdk-glibc' (but /home/flk/yocto/poky/meta/recipes-core/meta/uninative-tarball.bb RDEPENDS on or otherwise requires it)
> ERROR: nativesdk-glibc was skipped: PREFERRED_PROVIDER_virtual/nativesdk-x86_64-oesdk-linux-libc-for-gcc set to nativesdk-uclibc, not nativesdk-glibc
> NOTE: Runtime target 'nativesdk-glibc' is unbuildable, removing...
> Missing or unbuildable dependency chain was: ['nativesdk-glibc']
> ERROR: Required build target 'neutrino-image' has no buildable providers.
> Missing or unbuildable dependency chain was: ['neutrino-image', 'uninative-tarball', 'nativesdk-glibc']
>
> Summary: There was 1 WARNING message shown.
> Summary: There were 2 ERROR messages shown, returning a non-zero exit code.
>
> Building the image with TCLIBC = „glibc“ just works fine. i´m also capable to build an uclibc image with poky using the jethro branch without errors
>
> any ideas,
>
> Markus Volk
> --
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> yocto mailing list
> yocto@yoctoproject.org
> https://lists.yoctoproject.org/listinfo/yocto

uClibc

[Jerome Brown]

Will Xen run if compiled against uClibc? What about with the busybox 
toolset?

I am looking to create a minimal dom0 image that simply controls the 
creation and loading of new domains, and that allows migration to occur.


-- 
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Re: uClibc

[Jacob Gorm Hansen]

Jerome Brown wrote:
> Will Xen run if compiled against uClibc? What about with the busybox 
> toolset?

I don't think Xen itself is compiled against any libc. I have a 
busybox-based (though using glibc right now) initrd which you can use 
for your unprivileged domains. You can download it from 
http://www.diku.dk/~jacobg/self-migration/

> I am looking to create a minimal dom0 image that simply controls the 
> creation and loading of new domains, and that allows migration to occur.

I am working on exactly the same thing, though I am using self-migration 
in XenLinux rather than the managed migration in Xen. I am already able 
to migrate to a minimal Xen-host (the network-facing privileged code is 
about 50 lines of C, there is not even a TCP/IP stack running), and I am 
currenly working on being able to create new domains using the same 
mechanism (almost there).

I am currently on Xen 1.3, because the current Xend is too 
resource-hungry and complex for my needs. I am crossing my fingers for 
someone to implement the basics of Xend in C, and when that happens I 
plan to move to Xen 2.0.

Input and cooperation is welcomed.

Jacob



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Re: uClibc

[Jerome Brown]

Jacob Gorm Hansen wrote:
> I don't think Xen itself is compiled against any libc. I have a 
> busybox-based (though using glibc right now) initrd which you can use 
> for your unprivileged domains. You can download it from 
> http://www.diku.dk/~jacobg/self-migration/

What size does this run at? I am looking to make dom0 as small as 
possible, and run all the applications that I require under other 
domains, to allow moving them to other machines if required.

> I am working on exactly the same thing, though I am using self-migration 
> in XenLinux rather than the managed migration in Xen. I am already able 
> to migrate to a minimal Xen-host (the network-facing privileged code is 
> about 50 lines of C, there is not even a TCP/IP stack running), and I am 
> currenly working on being able to create new domains using the same 
> mechanism (almost there).

How does the XenLinux self-migration differ from the Xen managed 
migration? What are the advantages of each option. I have only just 
started to look into this, so am not stuck to a specific way of doing 
things at this stage :)

> I am currently on Xen 1.3, because the current Xend is too 
> resource-hungry and complex for my needs. I am crossing my fingers for 
> someone to implement the basics of Xend in C, and when that happens I 
> plan to move to Xen 2.0.

How do the resources used differ? Is Xend currently in python? Is there 
a plan to change this? What has been the reasoning behind developing it 
in python?

> Input and cooperation is welcomed.

I'd love to help. I like the idea of a 'self installing' dom0 that sets 
up another control domain, thereby abstracting all the running processes 
into unprivileged domains for security reasons. As part of this I will 
look to create a HowTo document that details how I acheive this :)

Regards

Jerome


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Re: uClibc

[Jacob Gorm Hansen]

Jerome Brown wrote:

> What size does this run at? I am looking to make dom0 as small as 
> possible, and run all the applications that I require under other 
> domains, to allow moving them to other machines if required.

I would image this to be the sum of Xen, a XenLinux with the TCP-stack 
removed, and a few hundred kilobytes of initrd with my tools.

> How does the XenLinux self-migration differ from the Xen managed 
> migration? What are the advantages of each option. I have only just 
> started to look into this, so am not stuck to a specific way of doing 
> things at this stage :)

Self-migration means that the unprivileged domain uses its own resources 
  (pager and TCP stack are the main ones), to checkpoint itself onto 
another host. There are pros and cons to both approaches, I refer you to 
my SIGOPS European Workshop paper, available from 
http://www.diku.dk/~jacobg/ for more details.

> How do the resources used differ? Is Xend currently in python? Is there 
> a plan to change this? What has been the reasoning behind developing it 
> in python?

I am not sure what the exact reasoning behind this decision was, but I 
am sure other people on this list would like to comment. I rewrote all 
my own tools in C a while back, something I do not regret at this point.

 From what I hear dom0 with Xend needs 32-64 megs to run. In my setup 4 
megs should be a realistic target.

> I'd love to help. I like the idea of a 'self installing' dom0 that sets 
> up another control domain, thereby abstracting all the running processes 
> into unprivileged domains for security reasons. As part of this I will 
> look to create a HowTo document that details how I acheive this :)

See if you can get any of the stuff on my page to run (both sources and 
binaries are provided), and feel free to ask questions if you can't 
(though I am on my way home fairly soon).

Best regards,
Jacob


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Re: uClibc

[Kip Macy]

> I am not sure what the exact reasoning behind this decision was, but I
> am sure other people on this list would like to comment. I rewrote all
> my own tools in C a while back, something I do not regret at this point.
>
>  From what I hear dom0 with Xend needs 32-64 megs to run. In my setup 4
> megs should be a realistic target.


At the risk of starting the construction of a bikeshed, what kind of
hardware are you running on? The reason for the increased appeal of
virtual machines over the past few years is that hw performance and
memory availability has increased faster than applications' needs.


				-Kip


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Re: uClibc

[Jacob Gorm Hansen]

Kip Macy wrote:

> At the risk of starting the construction of a bikeshed, what kind of
> hardware are you running on? The reason for the increased appeal of
> virtual machines over the past few years is that hw performance and
> memory availability has increased faster than applications' needs.

I am running on 2.4GHz Dell Optiplexes with 512MB of memory and no swap 
configured for dom0. Currently I have 16 of them, but in the long run I 
am hoping to run this on 1000+ nodes with similar config. That means any 
memory I waste I can multiply with an arbitrarily large number to make 
it sound scary.

My approach has (to me) many other nice properties, apart from the 
memory footprint, some of the more important ones being security (much 
reduced trusted computing base) and performance+isolation (not using 
shadow page tables, not relying on an external checkpointing service in 
dom0, being able to delay scheduling badly behaving processes during 
migration, knowing who is in my ARP cache, etc.), as well as overall 
better alignment with Saltzer's end-to-end argument.

I would like to create a platform where anyone can purchase resources, 
without any kind of trust that customer are playing nice, and I think 
that I am on the right path.

Before Xen came along, I created a similar platform (called NomadBIOS), 
based on L4, sporting what I now call hosted or managed migration. The 
system I am building now is my 'second system', for better or worse ;-) 
  I probably spent more time thinking about these issues than most 
people (though that is no guarantee that my conclusions are correct).

 > -Kip

Jacob


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Re: uClibc

[Jacob Gorm Hansen]

Kip Macy wrote:

> At the risk of starting the construction of a bikeshed, what kind of
> hardware are you running on? The reason for the increased appeal of
> virtual machines over the past few years is that hw performance and
> memory availability has increased faster than applications' needs.

I am running on 2.4GHz Dell Optiplexes with 512MB of memory and no swap
configured for dom0. Currently I have 16 of them, but in the long run I
am hoping to run this on 1000+ nodes with similar config. That means any
memory I waste I can multiply with an arbitrarily large number to make
it sound scary.

My approach has (to me) many other nice properties, apart from the
memory footprint, some of the more important ones being security (much
reduced trusted computing base) and performance+isolation (not using
shadow page tables, not relying on an external checkpointing service in
dom0, being able to delay scheduling badly behaving processes during
migration, knowing who is in my ARP cache, etc.), as well as overall
better alignment with Saltzer's end-to-end argument.

I would like to create a platform where anyone can purchase resources,
without any kind of trust that customer are playing nice, and I think
that I am on the right path.

Before Xen came along, I created a similar platform (called NomadBIOS),
based on L4, sporting what I now call hosted or managed migration. The
system I am building now is my 'second system', for better or worse ;-)
  I probably spent more time thinking about these issues than most
people (though that is no guarantee that my conclusions are correct).

> -Kip

Jacob


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Re: uClibc

[Mark Williamson]

> How do the resources used differ?

I can't put exact numbers on it but using Python will certainly result in a 
larger memory footprint being necessary for domain 0.

Python's not an enormously fast language but that doesn't matter too much for 
control plane functionality (performance critical stuff is coded in C 
already).

> Is Xend currently in python?

The control tools and Xend are written in Python.

The migration / suspend daemon (xfrd) is also coded in C for performance 
reasons.

> Is there 
> a plan to change this? What has been the reasoning behind developing it
> in python?

The use of Python in Xend enables rapid development - Xend does _a lot_ of 
different tasks, so it's good to have as much high-level goodness on your 
side as possible.  I don't think we're likely to change language in the near 
future.

Compared to the amount of memory spent on other domains, Xend's footprint is 
arguably still likely to be pretty small, although obviously it depends 
somewhat on the application.

The lowlevel functions for interfacing to Xen are available in a separate C 
library so it's possible to hook arbitrary languages into Xen.  It's 
certainly possible for Xend to be rewritten in C but it would be a large job 
to provide equivalent functionality.

An alternative control daemon called "x2d2" is in the unstable tree (what 
about the testing tree?  not sure...) but this is intended for developer 
experimentation and is not a full-blown Xend replacement.

Cheers,
Mark

>
> > Input and cooperation is welcomed.
>
> I'd love to help. I like the idea of a 'self installing' dom0 that sets
> up another control domain, thereby abstracting all the running processes
> into unprivileged domains for security reasons. As part of this I will
> look to create a HowTo document that details how I acheive this :)
>
> Regards
>
> Jerome
>
>
> -------------------------------------------------------
> SF email is sponsored by - The IT Product Guide
> Read honest & candid reviews on hundreds of IT Products from real users.
> Discover which products truly live up to the hype. Start reading now.
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