[lxc-devel] [PATCH 3/9] lxc_start: ERROR if container is already running.

[vivo75 at gmail.com]

Il 22/10/2014 17:43, Dwight Engen ha scritto:
> On Wed, 22 Oct 2014 14:31:15 +0000
> Serge Hallyn <serge.hallyn at ubuntu.com> wrote:
>
>> Quoting Alexandru Gheorghe (alghe.global at gmail.com):
>>> On 10/21/2014 07:54 PM, Serge Hallyn wrote:
>>>> Quoting Dwight Engen (dwight.engen at oracle.com):
>>>>> On Tue, 21 Oct 2014 09:58:29 -0500
>>>>> Tycho Andersen <tycho.andersen at canonical.com> wrote:
>>>>>
>>>>>> On Tue, Oct 21, 2014 at 02:54:34PM +0000, Serge Hallyn wrote:
>>>>>>> Quoting Tycho Andersen (tycho.andersen at canonical.com):
>>>>>>>> On Tue, Oct 21, 2014 at 02:29:28PM +0000, Serge Hallyn wrote:
>>>>>>>>> Quoting Tycho Andersen (tycho.andersen at canonical.com):
>>>>>>>>>> On Fri, Oct 10, 2014 at 11:16:54AM +0800, Dongsheng Yang
>>>>>>>>>> wrote:
>>>>>>>>>>> We should exit with a error when starting a running
>>>>>>>>>>> container.
>>>>>>>>>> Is this intentional? I just noticed it when pulling from
>>>>>>>>>> master that it breaks some of my scripts. Are we sure it
>>>>>>>>>> doesn't break anything else?
>>>>>>>>> Which scripts does it break?
>>>>>>>> No public ones, just some that I wrote myself. Just curious
>>>>>>>> if the behavior change was intentional or not (I prefer the
>>>>>>>> previous behavior :)
>>>>>>> What exactly is the change?  Did it used to return true
>>>>>>> instead of false?  The intent was simply to shortcut a bunch
>>>>>>> of extra work in the case where the container was already
>>>>>>> running.
>>>>>> Yes, sorry. It used to exit 0 instead of 1 when the container
>>>>>> was already running (and didn't print any ERROR or anything).
>>>>> I also find this a bit inconsistent, we purposefully don't
>>>>> report an error when doing stop on an already stopped container
>>>>> (see the early return 0 in lxc_cmd_stop()). I think it can be
>>>>> argued that its not an error since the command did what the
>>>>> caller wanted (ensure the container is started/stopped).
>>>> Ok - I don't want to revert the patch, but am happy to have it
>>>> return 0.
>>> Why not return a different code, like 5, when is already running
>>> (and trying to start)/stopped (and trying to stop it), so wrappers
>>> can detect this and use the information further?
>> Yup, that sounds good.  I could just do it I suppose, I've just been
>> waiting for someone to send a patch :)
> Won't that still break shell scripts that are testing $?
And init scripts generally return 0 and output a warning if the service
is already started, it may be wise to follow the convention

>  
>>> Could this be useful? At least it will allow some more handling by
>>> knowing if it's an error (1) or it really succeeded (0), and that is
>>> already in the state wanted (5) when tried so.
>>>
>>> --
>>> ; Alexandru Gheorghe
>>> ; alghe.global {at} gmail {dot} com
>>> ; OpenPGP key ID 0xCAF985D2
>>>