[openstack-dev] Stateful Applications on OpenStack

Georgy Okrokvertskhov gokrokvertskhov at mirantis.com
Mon Jun 9 17:04:10 UTC 2014


Hi Hossein,

In additions you may check the following:
Heat OS::Heat::HARestarter resource
http://docs.openstack.org/developer/heat/template_guide/openstack.html
This blog entry about clustering:
http://vmtrooper.com/openstack-your-windows-cluster-with-neutron-allowed-address-pairs/
Mistral project, specifically for Live migration:
https://wiki.openstack.org/wiki/Mistral#Live_migration
Murano project for legacy app management and composing:
https://wiki.openstack.org/wiki/Murano/ProjectOverview

Thanks,
Georgy


On Mon, Jun 9, 2014 at 9:30 AM, hossein zabolzadeh <zabolzadeh at gmail.com>
wrote:

> Really thanks Georgy for your complete answer. My major concern on
> openstack was HA on my legacy apps(I wanted to use cloudstack instead of
> openstack becasue of its more attention to legacy apps and more HA
> features). But now, I will check your listed HA solutions on openstack and
> come back as soon as possible.
>
>
> On Mon, Jun 9, 2014 at 8:53 PM, Georgy Okrokvertskhov <
> gokrokvertskhov at mirantis.com> wrote:
>
>> Hi,
>>
>> You still can run legacy application on OpenStack with HA and DR using
>> the same good old school tools like pacemaker, heartbeat, DRBD etc. There
>> are all necessary features available in latest OpenStack. The most
>> important feature for HA - secondary IP address was implemented in Havana.
>> Now you can assign multiple IP addresses to the single VM port. Secondary
>> IP can be used as a VIP in pacemaker so it is possible to create classic
>> Active-Passive setup for any application. HAProxy is still there an you can
>> use it for any application which uses IP based transport for communication.
>> This secondary IP feature allows you to run even Windows cluster
>> applications without any significant changes in setup in comparison to the
>> running cluster on physical nodes.
>>
>> There is no shared volumes (yet as I know) but you can use DRBD on VM to
>> sync two volumes attached to two different VMs and shared network
>> filesystems as a service is almost there. Using these approaches it is
>> possible to have data resilience for legacy applications too.
>>
>> There is no automagic things which make legacy apps resilient, but it is
>> still possible to do with using known tools as there are no limitations
>> from OpenStack infrastructure side for that. As I know there were
>> discussions about exposing HA clusters on hypervisors that will allow some
>> kind of resilience automatically (through automatic migrations or
>> evacuation) but there is no active work on it visible.
>>
>> Thanks
>> Georgy
>>
>>
>>
>>
>>
>> On Mon, Jun 9, 2014 at 7:16 AM, Matthew Farina <matt at mattfarina.com>
>> wrote:
>>
>>> In my experience building apps that run in OpenStack, you don't give
>>> up state. You shift how you handle state.
>>>
>>> For example, instead of always routing a user to the same instance and
>>> that instance holding the session data there is a common session store
>>> for the app (possibly synced between regions). If you store session on
>>> each instance and loose an instance you'll run into problems. If
>>> sessions is more of a service for each instance than an instance
>>> coming and going isn't a big deal.
>>>
>>> A good database as a service, swift (object storage), and maybe a
>>> microservice architecture may be helpful.
>>>
>>> Legacy applications might have some issues with the architecture
>>> changes and some may not be a good fit for cloud architectures. One
>>> way to help legacy applications is to use block storage, keep the
>>> latest snapshot of the instance in glance (image service), and monitor
>>> an instance. If an instance goes offline you can easily create a new
>>> one from the image and mount block storage with the data.
>>>
>>> - Matt
>>>
>>>
>>>
>>> On Mon, Jun 9, 2014 at 7:27 AM, hossein zabolzadeh <zabolzadeh at gmail.com>
>>> wrote:
>>> > Hi OpenStack Development Community,
>>> > I know that the OpenStack interest is to become a cloud computing
>>> operating
>>> > system. And this simple sentence means: "Say goodbye to Statefull
>>> > Applications".
>>> > But, as you know we are in the transition phase from stateful apps to
>>> > stateless apps(Remember Pets and Cattle Example). Legacy apps are
>>> still in
>>> > used and how openstack can address the problems of running stateful
>>> > applications(e.g. HA, DR, FT, R,...)?
>>> > HA: High Availability
>>> > DR: Disaster Recovery
>>> > FT: Fault Tolerance
>>> > R: Resiliancy!
>>> >
>>> > _______________________________________________
>>> > OpenStack-dev mailing list
>>> > OpenStack-dev at lists.openstack.org
>>> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>> >
>>>
>>> _______________________________________________
>>> OpenStack-dev mailing list
>>> OpenStack-dev at lists.openstack.org
>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>>
>>
>>
>>
>> --
>> Georgy Okrokvertskhov
>> Architect,
>> OpenStack Platform Products,
>> Mirantis
>> http://www.mirantis.com
>> Tel. +1 650 963 9828
>> Mob. +1 650 996 3284
>>
>> _______________________________________________
>> OpenStack-dev mailing list
>> OpenStack-dev at lists.openstack.org
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>
>>
>
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>
>


-- 
Georgy Okrokvertskhov
Architect,
OpenStack Platform Products,
Mirantis
http://www.mirantis.com
Tel. +1 650 963 9828
Mob. +1 650 996 3284
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