[SSSD] [PATCH] Exit offline mode only if server is available.

Michal Židek mzidek at redhat.com
Wed Jul 9 13:35:42 UTC 2014


On 07/07/2014 07:33 PM, Michal Židek wrote:
> On 07/07/2014 03:09 PM, Michal Židek wrote:
>> On 07/07/2014 03:01 PM, Jakub Hrozek wrote:
>>> On Mon, Jul 07, 2014 at 02:11:52PM +0200, Michal Židek wrote:
>>>> On 07/06/2014 06:44 PM, Simo Sorce wrote:
>>>>> On Sun, 2014-07-06 at 12:42 -0400, Simo Sorce wrote:
>>>>>> On Fri, 2014-07-04 at 12:34 +0200, Michal Židek wrote:
>>>>>>> Hi Sumit,
>>>>>>>
>>>>>>> actually your suggestion was one of my first ideas, but
>>>>>>> It looked like strange behaviour to me if the first
>>>>>>> getent (or any request for data not present int the
>>>>>>> cache) after offline_timeout period returned nothing
>>>>>>> even if the server was already available and the second
>>>>>>> (1 or 2 seconds after the first) returned proper data. I
>>>>>>> thought this may be considered a bug for some people (even
>>>>>>> if it is not a major regression :) ). The patch I sent
>>>>>>> was then an improvement over this initial idea (from my POV).
>>>>>>>
>>>>>>> I understand your suggestion and concern, but I would
>>>>>>> prefer to stick with the approach in the patch I sent.
>>>>>>
>>>>>> Can we at least use a backoff scheme where we increase timeout
>>>>>> periods
>>>>>> every time we try and find ourselves offline ?
>>>>>>
>>>>>> Try 1 minute, then 2, then 4, then 8, 16, 32, 64, 128 ...
>>>>
>>>> Good idea, but this might result in SSSD being too long
>>>> offline for no good reason. Would it make sense
>>>> to introduce a new config option for upper bound of
>>>> this delay (like offline_timeout_max)? Without this option
>>>> it would be difficult for me to accept this change. But
>>>> I wonder what the default value should be... maybe 64?
>>>
>>> I would actually prefer to have a sane default..one hour with some
>>> randomization to avoid "8AM flood" maybe.
>>>
>>>>
>>>>>
>>>>> It would also probably be a good idea to randomize a little the delay,
>>>>> otherwise we risk thundering herd situations.
>>>>>
>>>>> Simo.
>>>>>
>>>>
>>>> Should the maximal value of the random offset be configurable?
>>>
>>> I would prefer to have neither the random offset nor the maximum cap
>>> configurable, or have a undocumented option unless we know it makes
>>> sense to let the admin configure the option.
>>>
>>> I'm afraid we have too many timeout options already and it's difficult
>>> for admins to know them even without adding onother one..
>>>
>>
>> That is true. I will hardcode the values then.
>>
>>>> Or is it not needed (I personally think it is not, but would like
>>>> to hear other opinions as well)? I am also not sure what the
>>>> default value should be (I was thinking 30 seconds).
>>>>
>>>> Will send new patches soon, thanks for suggestions.
>>>>
>>>> Michal
>>>
>
> Here are the new patches. The hardcoded values are
> 30 seconds for the maximum random offset
> 3600 seconds for the maximum backoff delay
>
> Michal
>

Btw. I intentionally did not send the patches for 1.11.
I will send them after the patches for master are
accepted.

Thanks,
Michal




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