drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[Lingfei Kong]

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Hello,
When i create a guest with option 'cpus="0-3"' on the command line, xl can not parse the config. But it works well when i specify 'cpus=1' on the command line. I read the man page xl.cfg, learned that xl support the following format:
"0-3,5,^1"
so  it would be very nice if xl can support this format on the command line too.

Also i have file a bug on bugzilla: Bug 1886 - option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line



The following are the  details:

Description of problem:
option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line.

Version-Release number of selected component (if applicable):

How reproducible:
100%

Steps to Reproduce:
1. Install a host with xen4
2. Create a guest, add option 'cpus="0-3"' on the command line
# xl -v create hvm-7.0-64-1.cfg cpus="0-3"
Parsing config from hvm-7.0-64-1.cfg
hvm-7.0-64-1.cfg:28: config parsing error near `-3': lexical error
warning: Config file looks like it contains Python code.
warning:  Arbitrary Python is no longer supported.
warning:  See http://wiki.xen.org/wiki/PythonInXlConfig
Failed to parse config: Invalid argument


Actual results:
Failed to create the guest

Expected results:
Guest can be created successfully.

Additional info:
# xl info
host                   : hp-z220-02.qe.lab.eng.nay.redhat.com
release                : 3.11.10-301.fc20.x86_64
version                : #1 SMP Thu Dec 5 14:01:17 UTC 2013
machine                : x86_64
nr_cpus                : 8
max_cpu_id             : 7
nr_nodes               : 1
cores_per_socket       : 4
threads_per_core       : 2
cpu_mhz                : 3392
hw_caps                : bfebfbff:28100800:00000000:00007f00:77bae3ff:00000000:00000001:00000281
virt_caps              : hvm hvm_directio
total_memory           : 16258
free_memory            : 10185
sharing_freed_memory   : 0
sharing_used_memory    : 0
outstanding_claims     : 0
free_cpus              : 0
xen_major              : 4
xen_minor              : 3
xen_extra              : .2
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          : 
xen_commandline        : placeholder
cc_compiler            : gcc (GCC) 4.8.2 20131212 (Red Hat 4.8.2-7)
cc_compile_by          : mockbuild
cc_compile_domain      : [unknown]
cc_compile_date        : Wed Mar 26 20:46:37 UTC 2014
xend_config_format     : 4


The attachment is the log file /var/log/xen/xl-${DOMNAME}.log 

Best Regards
Lingfei Kong

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Waiting for domain hvm-7.0-64-1 (domid 5) to die [pid 16670]
Domain 5 has been destroyed.

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_______________________________________________
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Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

Is: Xen 4.4 and 'cpus="X-Y" command line parsing borked Was:Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[Konrad Rzeszutek Wilk]

On Thu, Apr 17, 2014 at 09:40:46PM -0400, Lingfei Kong wrote:
> Hello,
> When i create a guest with option 'cpus="0-3"' on the command line, xl can not parse the config. But it works well when i specify 'cpus=1' on the command line. I read the man page xl.cfg, learned that xl support the following format:
> "0-3,5,^1"
> so  it would be very nice if xl can support this format on the command line too.
> 
> Also i have file a bug on bugzilla: Bug 1886 - option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line
> 

On what bugzilla system?

> 
> 
> The following are the  details:
> 
> Description of problem:
> option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line.
> 
> Version-Release number of selected component (if applicable):
> 
> How reproducible:
> 100%
> 
> Steps to Reproduce:
> 1. Install a host with xen4

How did you install that? Did you use the Xen RPMs?

> 2. Create a guest, add option 'cpus="0-3"' on the command line
> # xl -v create hvm-7.0-64-1.cfg cpus="0-3"
> Parsing config from hvm-7.0-64-1.cfg

Does it work if you have the 'cpus="0-3"' in the guest config file
(from hvm-7.0-64-1.cfg)

> hvm-7.0-64-1.cfg:28: config parsing error near `-3': lexical error
> warning: Config file looks like it contains Python code.
> warning:  Arbitrary Python is no longer supported.
> warning:  See http://wiki.xen.org/wiki/PythonInXlConfig
> Failed to parse config: Invalid argument
> 
> 
> Actual results:
> Failed to create the guest
> 
> Expected results:
> Guest can be created successfully.
> 
> Additional info:
> # xl info
> host                   : hp-z220-02.qe.lab.eng.nay.redhat.com
> release                : 3.11.10-301.fc20.x86_64
> version                : #1 SMP Thu Dec 5 14:01:17 UTC 2013
> machine                : x86_64
> nr_cpus                : 8
> max_cpu_id             : 7
> nr_nodes               : 1
> cores_per_socket       : 4
> threads_per_core       : 2
> cpu_mhz                : 3392
> hw_caps                : bfebfbff:28100800:00000000:00007f00:77bae3ff:00000000:00000001:00000281
> virt_caps              : hvm hvm_directio
> total_memory           : 16258
> free_memory            : 10185
> sharing_freed_memory   : 0
> sharing_used_memory    : 0
> outstanding_claims     : 0
> free_cpus              : 0
> xen_major              : 4
> xen_minor              : 3
> xen_extra              : .2
> xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 
> xen_scheduler          : credit
> xen_pagesize           : 4096
> platform_params        : virt_start=0xffff800000000000
> xen_changeset          : 
> xen_commandline        : placeholder
> cc_compiler            : gcc (GCC) 4.8.2 20131212 (Red Hat 4.8.2-7)
> cc_compile_by          : mockbuild
> cc_compile_domain      : [unknown]
> cc_compile_date        : Wed Mar 26 20:46:37 UTC 2014
> xend_config_format     : 4
> 
> 
> The attachment is the log file /var/log/xen/xl-${DOMNAME}.log 
> 
> Best Regards
> Lingfei Kong

> Waiting for domain hvm-7.0-64-1 (domid 5) to die [pid 16670]
> Domain 5 has been destroyed.

> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel

Re: Is: Xen 4.4 and 'cpus="X-Y" command line parsing borked Was:Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[Lingfei Kong]

On 04/21/2014 09:02 PM, Konrad Rzeszutek Wilk wrote:
> On Thu, Apr 17, 2014 at 09:40:46PM -0400, Lingfei Kong wrote:
>> Hello,
>> When i create a guest with option 'cpus="0-3"' on the command line, xl can not parse the config. But it works well when i specify 'cpus=1' on the command line. I read the man page xl.cfg, learned that xl support the following format:
>> "0-3,5,^1"
>> so  it would be very nice if xl can support this format on the command line too.
>>
>> Also i have file a bug on bugzilla: Bug 1886 - option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line
>>
> 
> On what bugzilla system?
> 

I follow the steps descripted in xl command's man page. Here is the link
of this bug:  http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=1886

>>
>>
>> The following are the  details:
>>
>> Description of problem:
>> option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line.
>>
>> Version-Release number of selected component (if applicable):
>>
>> How reproducible:
>> 100%
>>
>> Steps to Reproduce:
>> 1. Install a host with xen4
> 
> How did you install that? Did you use the Xen RPMs?

Yes. Here are my steps
1. Install Fedora20
2. Install xen packages
#yum -y install xen
3. Configure grub2.cfg, Set 'Fedora, with Xen hypervisor' as the default
menuentry and reboot the host
4. Use option `cpus="0-3"` on the command line to create the guest

> 
>> 2. Create a guest, add option 'cpus="0-3"' on the command line
>> # xl -v create hvm-7.0-64-1.cfg cpus="0-3"
>> Parsing config from hvm-7.0-64-1.cfg
> 
> Does it work if you have the 'cpus="0-3"' in the guest config file
> (from hvm-7.0-64-1.cfg)
> 

When I specify it in t he guest config file, it works well.

>> hvm-7.0-64-1.cfg:28: config parsing error near `-3': lexical error
>> warning: Config file looks like it contains Python code.
>> warning:  Arbitrary Python is no longer supported.
>> warning:  See http://wiki.xen.org/wiki/PythonInXlConfig
>> Failed to parse config: Invalid argument
>>
>>
>> Actual results:
>> Failed to create the guest
>>
>> Expected results:
>> Guest can be created successfully.
>>
>> Additional info:
>> # xl info
>> host                   : hp-z220-02.qe.lab.eng.nay.redhat.com
>> release                : 3.11.10-301.fc20.x86_64
>> version                : #1 SMP Thu Dec 5 14:01:17 UTC 2013
>> machine                : x86_64
>> nr_cpus                : 8
>> max_cpu_id             : 7
>> nr_nodes               : 1
>> cores_per_socket       : 4
>> threads_per_core       : 2
>> cpu_mhz                : 3392
>> hw_caps                : bfebfbff:28100800:00000000:00007f00:77bae3ff:00000000:00000001:00000281
>> virt_caps              : hvm hvm_directio
>> total_memory           : 16258
>> free_memory            : 10185
>> sharing_freed_memory   : 0
>> sharing_used_memory    : 0
>> outstanding_claims     : 0
>> free_cpus              : 0
>> xen_major              : 4
>> xen_minor              : 3
>> xen_extra              : .2
>> xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 
>> xen_scheduler          : credit
>> xen_pagesize           : 4096
>> platform_params        : virt_start=0xffff800000000000
>> xen_changeset          : 
>> xen_commandline        : placeholder
>> cc_compiler            : gcc (GCC) 4.8.2 20131212 (Red Hat 4.8.2-7)
>> cc_compile_by          : mockbuild
>> cc_compile_domain      : [unknown]
>> cc_compile_date        : Wed Mar 26 20:46:37 UTC 2014
>> xend_config_format     : 4
>>
>>
>> The attachment is the log file /var/log/xen/xl-${DOMNAME}.log 
>>
>> Best Regards
>> Lingfei Kong
> 
>> Waiting for domain hvm-7.0-64-1 (domid 5) to die [pid 16670]
>> Domain 5 has been destroyed.
> 
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xen.org
>> http://lists.xen.org/xen-devel
> 


Thanks and Best Regards
Lingfei Kong

Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[George Dunlap]

On Fri, Apr 18, 2014 at 2:40 AM, Lingfei Kong <lkong@redhat.com> wrote:
> Hello,
> When i create a guest with option 'cpus="0-3"' on the command line, xl can not parse the config. But it works well when i specify 'cpus=1' on the command line. I read the man page xl.cfg, learned that xl support the following format:
> "0-3,5,^1"
> so  it would be very nice if xl can support this format on the command line too.
>
> Also i have file a bug on bugzilla: Bug 1886 - option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line
>
>
>
> The following are the  details:
>
> Description of problem:
> option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line.
>
> Version-Release number of selected component (if applicable):
>
> How reproducible:
> 100%
>
> Steps to Reproduce:
> 1. Install a host with xen4
> 2. Create a guest, add option 'cpus="0-3"' on the command line
> # xl -v create hvm-7.0-64-1.cfg cpus="0-3"
> Parsing config from hvm-7.0-64-1.cfg
> hvm-7.0-64-1.cfg:28: config parsing error near `-3': lexical error
> warning: Config file looks like it contains Python code.
> warning:  Arbitrary Python is no longer supported.
> warning:  See http://wiki.xen.org/wiki/PythonInXlConfig
> Failed to parse config: Invalid argument

The problem here is that your shell is discarding the quotes; so what
xl sees is 'cpus=0-3', not 'cpus="0-3"'.  Try the following:

# xl -v create hvm-7.0-64-1.cfg cpus=\"0-3\"

-George

Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[Lingfei Kong]

On 04/22/2014 06:59 PM, George Dunlap wrote:
> On Fri, Apr 18, 2014 at 2:40 AM, Lingfei Kong <lkong@redhat.com> wrote:
>> Hello,
>> When i create a guest with option 'cpus="0-3"' on the command line, xl can not parse the config. But it works well when i specify 'cpus=1' on the command line. I read the man page xl.cfg, learned that xl support the following format:
>> "0-3,5,^1"
>> so  it would be very nice if xl can support this format on the command line too.
>>
>> Also i have file a bug on bugzilla: Bug 1886 - option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line
>>
>>
>>
>> The following are the  details:
>>
>> Description of problem:
>> option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line.
>>
>> Version-Release number of selected component (if applicable):
>>
>> How reproducible:
>> 100%
>>
>> Steps to Reproduce:
>> 1. Install a host with xen4
>> 2. Create a guest, add option 'cpus="0-3"' on the command line
>> # xl -v create hvm-7.0-64-1.cfg cpus="0-3"
>> Parsing config from hvm-7.0-64-1.cfg
>> hvm-7.0-64-1.cfg:28: config parsing error near `-3': lexical error
>> warning: Config file looks like it contains Python code.
>> warning:  Arbitrary Python is no longer supported.
>> warning:  See http://wiki.xen.org/wiki/PythonInXlConfig
>> Failed to parse config: Invalid argument
> 
> The problem here is that your shell is discarding the quotes; so what
> xl sees is 'cpus=0-3', not 'cpus="0-3"'.  Try the following:
> 
> # xl -v create hvm-7.0-64-1.cfg cpus=\"0-3\"
> 
> -George
> 

Hi George,
Thanks for your hlep. It works with cpus=\"0-3\".


Lingfei Kong

Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[George Dunlap]

On 04/23/2014 01:56 AM, Lingfei Kong wrote:
> On 04/22/2014 06:59 PM, George Dunlap wrote:
>> On Fri, Apr 18, 2014 at 2:40 AM, Lingfei Kong <lkong@redhat.com> wrote:
>>> Hello,
>>> When i create a guest with option 'cpus="0-3"' on the command line, xl can not parse the config. But it works well when i specify 'cpus=1' on the command line. I read the man page xl.cfg, learned that xl support the following format:
>>> "0-3,5,^1"
>>> so  it would be very nice if xl can support this format on the command line too.
>>>
>>> Also i have file a bug on bugzilla: Bug 1886 - option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line
>>>
>>>
>>>
>>> The following are the  details:
>>>
>>> Description of problem:
>>> option `cpus="0-3"` works well when you specify it in a configure file, but it give a error feadback when you add it to the command line.
>>>
>>> Version-Release number of selected component (if applicable):
>>>
>>> How reproducible:
>>> 100%
>>>
>>> Steps to Reproduce:
>>> 1. Install a host with xen4
>>> 2. Create a guest, add option 'cpus="0-3"' on the command line
>>> # xl -v create hvm-7.0-64-1.cfg cpus="0-3"
>>> Parsing config from hvm-7.0-64-1.cfg
>>> hvm-7.0-64-1.cfg:28: config parsing error near `-3': lexical error
>>> warning: Config file looks like it contains Python code.
>>> warning:  Arbitrary Python is no longer supported.
>>> warning:  See http://wiki.xen.org/wiki/PythonInXlConfig
>>> Failed to parse config: Invalid argument
>> The problem here is that your shell is discarding the quotes; so what
>> xl sees is 'cpus=0-3', not 'cpus="0-3"'.  Try the following:
>>
>> # xl -v create hvm-7.0-64-1.cfg cpus=\"0-3\"
>>
>> -George
>>
> Hi George,
> Thanks for your hlep. It works with cpus=\"0-3\".

Actually, a better way would be to enclose the whole thing in single 
quotes, and separate variables with a ; like so:

# xl -v create hvm.cfg 'cpus="0-3"; memory=2048'

This should at very least be documented better -- I'll send a patch to 
update the xl man page.

  -George

Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[Lingfei Kong]

On 04/23/2014 06:58 PM, George Dunlap wrote:
> On 04/23/2014 01:56 AM, Lingfei Kong wrote:
>> On 04/22/2014 06:59 PM, George Dunlap wrote:
>>> On Fri, Apr 18, 2014 at 2:40 AM, Lingfei Kong <lkong@redhat.com> wrote:
>>>> Hello,
>>>> When i create a guest with option 'cpus="0-3"' on the command line,
>>>> xl can not parse the config. But it works well when i specify
>>>> 'cpus=1' on the command line. I read the man page xl.cfg, learned
>>>> that xl support the following format:
>>>> "0-3,5,^1"
>>>> so  it would be very nice if xl can support this format on the
>>>> command line too.
>>>>
>>>> Also i have file a bug on bugzilla: Bug 1886 - option `cpus="0-3"`
>>>> works well when you specify it in a configure file, but it give a
>>>> error feadback when you add it to the command line
>>>>
>>>>
>>>>
>>>> The following are the  details:
>>>>
>>>> Description of problem:
>>>> option `cpus="0-3"` works well when you specify it in a configure
>>>> file, but it give a error feadback when you add it to the command line.
>>>>
>>>> Version-Release number of selected component (if applicable):
>>>>
>>>> How reproducible:
>>>> 100%
>>>>
>>>> Steps to Reproduce:
>>>> 1. Install a host with xen4
>>>> 2. Create a guest, add option 'cpus="0-3"' on the command line
>>>> # xl -v create hvm-7.0-64-1.cfg cpus="0-3"
>>>> Parsing config from hvm-7.0-64-1.cfg
>>>> hvm-7.0-64-1.cfg:28: config parsing error near `-3': lexical error
>>>> warning: Config file looks like it contains Python code.
>>>> warning:  Arbitrary Python is no longer supported.
>>>> warning:  See http://wiki.xen.org/wiki/PythonInXlConfig
>>>> Failed to parse config: Invalid argument
>>> The problem here is that your shell is discarding the quotes; so what
>>> xl sees is 'cpus=0-3', not 'cpus="0-3"'.  Try the following:
>>>
>>> # xl -v create hvm-7.0-64-1.cfg cpus=\"0-3\"
>>>
>>> -George
>>>
>> Hi George,
>> Thanks for your hlep. It works with cpus=\"0-3\".
> 
> Actually, a better way would be to enclose the whole thing in single
> quotes, and separate variables with a ; like so:
> 
> # xl -v create hvm.cfg 'cpus="0-3"; memory=2048'
> 
> This should at very least be documented better -- I'll send a patch to
> update the xl man page.
> 
>  -George

Thanks for your explanation.
Maybe another solution is to change the xl command to adapt this. On
RHEL5 xen hypervisor, I can create a guest with `xm create hvm.cfg
cpus="0-3"`. As a user I prefer this method, because this will be
consistent with it's config file and it is strange to use ' to enclose
the parameters.


Best Regards
Lingfei Kong

Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[Ian Campbell]

On Thu, 2014-04-24 at 08:14 +0800, Lingfei Kong wrote:
> Maybe another solution is to change the xl command to adapt this.

Feel free to propose a patch but I suspect this would involve too much
surgery to the config file parser.

>  On
> RHEL5 xen hypervisor, I can create a guest with `xm create hvm.cfg
> cpus="0-3"`. As a user I prefer this method, because this will be
> consistent with it's config file and it is strange to use ' to enclose
> the parameters.

That is perfectly normal shell quoting behaviour, nothing strange about
it IMHO.

Ian.

Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[George Dunlap]

On 04/24/2014 09:44 AM, Ian Campbell wrote:
> On Thu, 2014-04-24 at 08:14 +0800, Lingfei Kong wrote:
>> Maybe another solution is to change the xl command to adapt this.
> Feel free to propose a patch but I suspect this would involve too much
> surgery to the config file parser.
>
>>   On
>> RHEL5 xen hypervisor, I can create a guest with `xm create hvm.cfg
>> cpus="0-3"`. As a user I prefer this method, because this will be
>> consistent with it's config file and it is strange to use ' to enclose
>> the parameters.
> That is perfectly normal shell quoting behaviour, nothing strange about
> it IMHO.

Well having the config file syntax include quotes and brackets is 
natural.  The fact that the shell interprets quotes and brackets is also 
natural.  But the combination of the two leads to a rather unexpected 
and clunky user interface.

Unfortunately I'm not sure what we can really do at this point to 
maintain the general flexibility while avoiding backticks.  We might be 
able to modify the parser for specific cases, such as the cpus one, to 
tolerate 'cpus=0-3' rather than the canonical 'cpus="0-3"'. But in the 
general case it would require re-writing the config format such that it 
can be written without requiring any characters treated specially by the 
shell; that's just a bit more work than it's really worth, I think.

  -George

Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[Ian Campbell]

On Thu, 2014-04-24 at 10:01 +0100, George Dunlap wrote:
> On 04/24/2014 09:44 AM, Ian Campbell wrote:
> > On Thu, 2014-04-24 at 08:14 +0800, Lingfei Kong wrote:
> >> Maybe another solution is to change the xl command to adapt this.
> > Feel free to propose a patch but I suspect this would involve too much
> > surgery to the config file parser.
> >
> >>   On
> >> RHEL5 xen hypervisor, I can create a guest with `xm create hvm.cfg
> >> cpus="0-3"`. As a user I prefer this method, because this will be
> >> consistent with it's config file and it is strange to use ' to enclose
> >> the parameters.
> > That is perfectly normal shell quoting behaviour, nothing strange about
> > it IMHO.
> 
> Well having the config file syntax include quotes and brackets is 
> natural.  The fact that the shell interprets quotes and brackets is also 
> natural.  But the combination of the two leads to a rather unexpected 
> and clunky user interface.

This happens all the time though, "in find -exec foo \;" in sed and perl
-e etc etc. It's just the way Unix shells work.

> Unfortunately I'm not sure what we can really do at this point to 
> maintain the general flexibility while avoiding backticks.

Hang on, how did we end up with backticks here? I think you just means
normal quotes?

>   We might be 
> able to modify the parser for specific cases, such as the cpus one, to 
> tolerate 'cpus=0-3' rather than the canonical 'cpus="0-3"'. But in the 
> general case it would require re-writing the config format such that it 
> can be written without requiring any characters treated specially by the 
> shell; that's just a bit more work than it's really worth, I think.

Yes, it isn't worth it IMHO either.

Ian

Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[George Dunlap]

On 04/24/2014 10:32 AM, Ian Campbell wrote:
> On Thu, 2014-04-24 at 10:01 +0100, George Dunlap wrote:
>> On 04/24/2014 09:44 AM, Ian Campbell wrote:
>>> On Thu, 2014-04-24 at 08:14 +0800, Lingfei Kong wrote:
>>>> Maybe another solution is to change the xl command to adapt this.
>>> Feel free to propose a patch but I suspect this would involve too much
>>> surgery to the config file parser.
>>>
>>>>    On
>>>> RHEL5 xen hypervisor, I can create a guest with `xm create hvm.cfg
>>>> cpus="0-3"`. As a user I prefer this method, because this will be
>>>> consistent with it's config file and it is strange to use ' to enclose
>>>> the parameters.
>>> That is perfectly normal shell quoting behaviour, nothing strange about
>>> it IMHO.
>> Well having the config file syntax include quotes and brackets is
>> natural.  The fact that the shell interprets quotes and brackets is also
>> natural.  But the combination of the two leads to a rather unexpected
>> and clunky user interface.
> This happens all the time though, "in find -exec foo \;" in sed and perl
> -e etc etc. It's just the way Unix shells work.

Maybe it would be more clear then, rather than saying "key=value pairs" 
in the man page, to say "a config file snippet"?  That might put people 
in the mindset of thinking more like "perl -e".

>
>> Unfortunately I'm not sure what we can really do at this point to
>> maintain the general flexibility while avoiding backticks.
> Hang on, how did we end up with backticks here? I think you just means
> normal quotes?

Actually I have no idea where that came from... you get the main idea 
though -- escape sequences or single quotes.

  -George

Re: drjones@redhat.com, vkuznets@redhat.com, leiwang@redhat.com, wshi@redhat.com

[Ian Campbell]

On Thu, 2014-04-24 at 12:27 +0100, George Dunlap wrote:
> On 04/24/2014 10:32 AM, Ian Campbell wrote:
> > On Thu, 2014-04-24 at 10:01 +0100, George Dunlap wrote:
> >> On 04/24/2014 09:44 AM, Ian Campbell wrote:
> >>> On Thu, 2014-04-24 at 08:14 +0800, Lingfei Kong wrote:
> >>>> Maybe another solution is to change the xl command to adapt this.
> >>> Feel free to propose a patch but I suspect this would involve too much
> >>> surgery to the config file parser.
> >>>
> >>>>    On
> >>>> RHEL5 xen hypervisor, I can create a guest with `xm create hvm.cfg
> >>>> cpus="0-3"`. As a user I prefer this method, because this will be
> >>>> consistent with it's config file and it is strange to use ' to enclose
> >>>> the parameters.
> >>> That is perfectly normal shell quoting behaviour, nothing strange about
> >>> it IMHO.
> >> Well having the config file syntax include quotes and brackets is
> >> natural.  The fact that the shell interprets quotes and brackets is also
> >> natural.  But the combination of the two leads to a rather unexpected
> >> and clunky user interface.
> > This happens all the time though, "in find -exec foo \;" in sed and perl
> > -e etc etc. It's just the way Unix shells work.
> 
> Maybe it would be more clear then, rather than saying "key=value pairs" 
> in the man page, to say "a config file snippet"?  That might put people 
> in the mindset of thinking more like "perl -e".

I thought (having glanced really quickly yesterday as I filed it in my
queue) that your proposed docs change looked pretty good.

Ian.