On Fri, May 2, 2014 at 7:12 AM, Alejandro Bonilla < [email protected]> wrote:
> Hi Akila, > > On Mon, Apr 21, 2014 at 8:38 AM, Akila Ravihansa Perera > <[email protected]> wrote: > > Hi, > > > > I'm working on creating a new cartridge for mongodb with auto-scaling > > support. So far 3 use-cases have been identified so far. > > > > 1. mongodb scales horizontally (mongodb with sharding cluster) > > 2. mongodb scales vertically (mongodb with replica cluster) > > 3. mongodb replicated sharding cluster > > Cool, you can make a cartridge using susestudio.com if you want, it > will take you 5 minutes. If you want one, I can provide it built > already. > > > I have successfully deployed mongodb single node instance as a Stratos > > cartridge by using this Puppet script [1]. However, implementing > > auto-scaling for the mongodb cartridge requires some work. > > > > For a start, I'll be working on the first use-case scenario (mongodb with > > sharding cluster). Following is a brief work plan. > > > > 1. mongos (query routers) and config servers will be bundled in a single > > "mongolb" instance (mongo load balancer) which will be subscribed > > automatically by Stratos as the load balancer. > > 2. mongod servers (shard servers) will be bundled as "mongodb" instances > > which will get scaled up or down. > > 3. When an instance is spawned, it will get added to the mongos cluster > by a > > Puppet script. > > Note - When implementing use-case scenario 2 and 3, Stratos Agent will > have > > to check the member list and depending on the member count, initialize > the > > replication set (master node) OR add the instance to the appropriate > > replication set. > > This is good stuff and how it should work, yet, I've been in touch > with Mongo architects and they claim few or no real customers use > auto-scaling :( - they do run into scalability issues and query > balancing race conditions since even if their transactions are atomic, > it does not guarantee the other replica sets will already have the > data. Also, scaling down servers may lead to weirdness depending on > the complexity of the application. > > Nevertheless, eventually this will take some traction and would be > interesting... > > Interesting.., will make our hand dirty on this and see what are the issues. Thanks Alejandro for finding, we may need to get some help form Mongo architects when we get there. > > > > Pl let me know your thoughts regarding this. > > > > [1] - https://github.com/echocat/puppet-mongodb > > > > Thanks. > > > > -- > > Akila Ravihansa Perera > > Software Engineer > > WSO2 Inc. > > http://wso2.com > > > > Phone: +94 77 64 154 38 > > Blog: http://ravihansa3000.blogspot.com > -- Lakmal Warusawithana Director - Cloud Architecture; WSO2 Inc. Mobile : +94714289692 Blog : http://lakmalsview.blogspot.com/
