fuel-dev team mailing list archive

[Sergii Golovatiuk <sgolovatiuk@xxxxxxxxxxxx>]

Hi Ryan,

All details are listed at https://bugs.launchpad.net/keystone/+bug/1332058

In short, memcache failover doesn't work as python-memcached doesn't have
enough options for that. libmemcached and python-pylibmc have more settings
for HA that was tested.

--
Best regards,
Sergii Golovatiuk,
Skype #golserge
IRC #holser


On Wed, Aug 6, 2014 at 12:46 AM, Ryan Moe <rmoe@xxxxxxxxxxxx> wrote:

> Hi Sergii,
>
> This sounds great. Can you elaborate on the specific behaviors you'd like
> to set with libmemcached and how they will help our situation?
>
> Thanks,
> Ryan
>
>
> On Tue, Aug 5, 2014 at 4:42 AM, Sergii Golovatiuk <
> sgolovatiuk@xxxxxxxxxxxx> wrote:
>
>> Hi Fuelers,
>>
>> While working on memcache HA issues I dug the problem, thus want to bring
>> up to your attention.
>>
>> Currently, MOS services (keystone, horizon) uses python-memcached plugin.
>> The plugin itself is not bad but lacks of features for High Availability.
>>
>> Firstly, it's not possible to specify how much time need to wait for an
>> answer before marking server as down. Also there are no way to specify how
>> often to check the server before bringing it back online.
>>
>> However, it's possible to use python-pylibmc which is wrapper over
>> limemcached that has many options for tuning. So it requires slight
>> modification
>> 1. We need to package libmemcached and python-pylibmc and include to MOS
>> 2. there should be additional option in keystone.conf > [cache] >
>> backend_behavior which will allow operators to specify options for memcache
>> backend. This requires a slight modification in keystone.
>>  3. We should package django-pylibmc for horizon. That will allow
>> horizon to use python-pylibmc
>> 4. Modify Puppet manifest in order to configure keystone and horizon as
>> well as to install all required packages.
>>
>> Once done, memcached related services will be more robust, allowing
>> operators to tune settings for their needs.
>>
>> Feel free to share your thoughts how to make memcached related services
>> HA ready. Thank you in advance.
>> --
>> Best regards,
>> Sergii Golovatiuk,
>> Skype #golserge
>> IRC #holser
>>
>> --
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>>
>