Re: [Xen-devel] [patch] Xen build - Debian vs Redhat layout patch options

[Bruce Edge <bruce.edge@xxxxxxxxx>]

On Tue, Sep 14, 2010 at 10:05 AM, Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx> wrote:
> Bruce Edge writes ("Re: [Xen-devel] [patch] Xen build - Debian vs Redhat 
> layout patch options"):
>> There are 2 locations that are not optimal for Debian based distributions.
>> These are /etc/sysconfig, and /var/subsys.
>> Debian uses /etc/default and /var for these respectively.
>
> Thanks for this contribution.  I have some comments:

Thanks for the hints Ian. I have some questions on your comments.

>
>> This patch provides a new make config variable, XEN_CONFIG_ARCH, which
>> changes the location of these 2 elements if set.
>
> I'm not sure that "XEN_CONFIG_ARCH" is the right answer.  What's wrong
> with simply setting SYSCONFIG_DIR ?  Perhaps SYSCONFIG_DIR needs to be
> defined with "?=" rather than "=" ?

In order to honor the $PREFIX setting, $SYSCONFIG_DIR has to depend on $PREFIX:

ifeq ($(PREFIX),/usr)
CONFIG_DIR = /etc
else
CONFIG_DIR = $(PREFIX)/etc
endif

SYSCONFIG_DIR = $(CONFIG_DIR)/$(XEN_CONFIG_ARCH)

So using ?= for the above would require that one manually add the
$PREFIX to whatever SYSCONFIG_DIR they wanted to use.

>
> If we do need a special variable for the leaf dir it should be called
> something else.  ARCH is for CPU architectures.

What's a good word to differentiate bewteen debian/red hat distros?

DISTRO_TYPE=<debian | redhat>

That would allow the addition of other distro types as neeeded.

>
>> For the runtime scripts it checks whether the Red Hat sysconfig files
>> exist first, then looks in the Debian location.
>> This lets the config files reside in the desired location and does not
>> require any additional runtime config file
>> to point to their location.
>
> This is good.
>
>>  Creating network initscripts
>>  ----------------------------
>>
>> -In the /etc/sysconfig/network-scripts directory it is necccessary to create
>> +In the <SYSCONFIG>/network-scripts directory it is necccessary to create
>>  2 config files. The first (ifcfg-eth0) defines your physical network 
>> interface,
>>  and says that it will be part of a bridge:
>
> This, and all the stuff that implicitly refers to files in
> /etc/default for host network configuration, is entirely wrong.
> Debian-derived distros have a different way of setting up networking
> and the files have a different syntax and semantics, as well as a
> different location.

I'll need to research this further. If anyone has any heuristics to suggest....

>
> It's only the files which are invented by the Xen distribution which
> might be found in /etc/sysconfig _or_ /etc/default.
>
>>  if [ -f /etc/sysconfig/xenballoon.conf ]; then
>>         . /etc/sysconfig/xenballoon.conf
>> +else
>> +       if [ -f /etc/default/xenballoon.conf ]; then
>
> Use elif ?

:-)

>
>> +if [ -d /etc/sysconfig ]; then
>> +       LOCKFILE=/var/lock/subsys/xendomains
>> +       XENDOM_CONFIG=/etc/sysconfig/xendomains
>> +else
>> +       LOCKFILE=/var/lock/xendomains
>> +       XENDOM_CONFIG=/etc/default/xendomains
>> +fi
>
> I don't think this is correct.  You should test for /etc/sysconfig and
> /var/lock/subsys separately, in case someone makes a mutant distro
> that has one but not the other.

Again, if I go with DISTRO_TYPE I could define a set of default
locations for each DISTRO_TYPE. That would allow std distros to work
with a master toggle and others to be customized as needed.

-Bruce

>
> Would you care to revise your patch and resubmit it ?
>
> Thanks,
> Ian.
>

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