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Re: Memcache HA issues

 

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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