[openstack-dev] [savanna] scalable architecture
joe.gordon0 at gmail.com
Tue Jul 30 19:33:21 UTC 2013
On Tue, Jul 30, 2013 at 3:56 AM, Ruslan Kamaldinov <rkamaldinov at mirantis.com
> This question was asked several times. So we decided to provide a
> detailed response.
> 1. The first question is “Why doesn’t Savanna use Heat to provision VMs?”
> Generally using Heat underneath for infrastructure provisioning looks
> reasonable. In a tactic perspective there are few factors making Heat
> usage underneath Savanna problematic:
> * Heat stability for Grizzly release. Savanna currently maintains
> Grizzly+ compatibility.
This shouldn't be an issue anymore. Now that we are in Havana
> * Installation of large Hadoop clusters (100+ nodes). Will be
> addressed by proposed architecture changes.
What about heat doesn't work for this?
> * Anti-affinity support for HDFS redundancy in cloud environment
Why can't heat do this
> * Circular dependencies - we should generate ‘/etc/hosts’ for all
> instances in provisioned cluster. We can’t use cloud init for this
> directly. There are a couple possible solutions using Heat, but none
> of them looks like a straightforward solution.
So why not make heat do this better
> * Level of complexity. We try to keep things as simple as possible.
> Adding extra layer will increase overall complexity of the solution.
> In addition both Savanna and Heat under active development changing
> lots of internals and even APIs and will require extra effort to
But coordinating will result in less duplicate work
> Here is what we’ll do:
> * Create a wiki page with text from this email
> * Create a list of requirements for Heat
> Once Heat fulfills all the requirements we will be able and should use
> Heat for VM provisioning.
Now that you have a basic working version of Savana, I would prefer to see
you help make heat fit work for you instead of reimplementing a subset of
what it is trying to do.
> 2. Let’s answer the second question - why we need Savanna? Can’t we
> use Heat to do what Savanna does?
> * Savanna provides bunch of Hadoop-specific features. It’ll be hard to
> provide them as Heat plugin
> * Savanna provides Hadoop-specific APIs and functionality. Heat use
> cases are mostly around provisioning/deployment.
> * Savanna provides integration with various Hadoop distributions
> through pluggable mechanism
> Now, more details on each item.
> Hadoop specific features:
> * Tight Swift integration. Hadoop can read and write from/to Swift
> object storage. Savanna provides required configs for the Hadoop
> * Usage of anti-affinity to preserve data-redundancy of HDFS nodes
> Hadoop-specific APIs and functionality:
> * Hadoop cluster scaling
> * Elastic Data Processing: https://wiki.openstack.org/wiki/Savanna/EDP
> Integration with Hadoop distributions through pluggable mechanism:
> - Usually Hadoop cluster deployment is a multi-step operation. First
> step is to install management console (for instance Apache Ambari).
> Second step is to communicate with management console through REST API
> to provision Hadoop on the cluster. Savanna wraps all this operations
> under well-defined API.
> I hope all the items above explain why we need Savanna as a separate
> OpenStack service.
> 3. Why can’t Savanna be used as a plugin for Heat?
> It should be and it will be someday.
> On Thu, Jul 25, 2013 at 7:42 PM, Joe Gordon <joe.gordon0 at gmail.com> wrote:
> > On Jul 23, 2013 12:34 PM, "Sergey Lukjanov" <slukjanov at mirantis.com>
> >> Hi evereyone,
> >> We’ve started working on upgrading Savanna architecture in version 0.3
> >> make it horizontally scalable.
> >> The most part of information is in the wiki page -
> >> https://wiki.openstack.org/wiki/Savanna/NextGenArchitecture.
> >> Additionally there are several blueprints created for this activity -
> >> https://blueprints.launchpad.net/savanna?searchtext=ng-
> >> We are looking for comments / questions / suggestions.
> > This sounds like most of this can be built around Heat, except maybe the
> > rest api to hadoop. So why not use heat for the deploy part?
> >> P.S. The another thing that we’re working on in Savanna 0.3 is EDP
> >> (Elastic Data Processing).
> >> Thank you!
> >> Sincerely yours,
> >> Sergey Lukjanov
> >> Savanna Technical Lead
> >> Mirantis Inc.
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