Seems a very good idea for cloud servers. Pls feel free to raise a JIRA and contribute your patch.
Regards Ram On Tue, Jun 18, 2019 at 8:09 AM 刘新星 <[email protected]> wrote: > > > I'm interested on this. It sounds like a weighted load balancer and > valuable for those users deploy their hbase cluster on cloud servers. > You can create a jira and make a patch for better discussion. > > > > > > > > At 2019-06-18 05:00:54, "Pierre Zemb" <[email protected]> wrote: > >Hi! > > > >My name is Pierre, I'm working at OVH, an European cloud-provider. Our > >team, Observability, is heavily relying on HBase to store telemetry. We > >would like to open the discussion about adding into 1.4X and 2.X a new > >Balancer. > >< > https://gist.github.com/PierreZ/15560e12c147e661e5c1b5f0edeb9282#our-situation > >Our > >situation > > > >The Observability team in OVH is responsible to handle logs and metrics > >from all servers/applications/equipments within OVH. HBase is used as the > >datastore for metrics. We are using an open-source software called Warp10 > ><https://warp10.io> to handle all the metrics coming from OVH's > >infrastructure. We are operating three HBase 1.4 clusters, including one > >with 218 RegionServers which is growing every month. > > > >We found out that *in our usecase*(single table, dedicated HBase and > Hadoop > >tuned for our usecase, good key distribution)*, the number of regions per > >RS was the real limit for us*. > > > >Over the years, due to historical reasons and also the need to benchmark > >new machines, we ended-up with differents groups of hardware: some servers > >can handle only 180 regions, whereas the biggest can handle more than 900. > >Because of such a difference, we had to disable the LoadBalancing to avoid > >the roundRobinAssigmnent. We developed some internal tooling which are > >responsible for load balancing regions across RegionServers. That was 1.5 > >year ago. > > > >Today, we are thinking about fully integrate it within HBase, using the > >LoadBalancer interface. We started working on a new Balancer called > >HeterogeneousBalancer, that will be able to fullfill our need. > >< > https://gist.github.com/PierreZ/15560e12c147e661e5c1b5f0edeb9282#how-does-it-works > >How > >does it works? > > > >A rule file is loaded before balancing. It contains lines of rules. A rule > >is composed of a regexp for hostname, and a limit. For example, we could > >have: > > > >rs[0-9] 200 > >rs1[0-9] 50 > > > >RegionServers with hostname matching the first rules will have a limit of > >200, and the others 50. If there's no match, a default is set. > > > >Thanks to the rule, we have two informations: the max number of regions > for > >this cluster, and the rules for each servers. HeterogeneousBalancer will > >try to balance regions according to their capacity. > > > >Let's take an example. Let's say that we have 20 RS: > > > > - 10 RS, named through rs0 to rs9 loaded with 60 regions each, and each > > can handle 200 regions. > > - 10 RS, named through rs10 to rs19 loaded with 60 regions each, and > > each can support 50 regions. > > > >Based on the following rules: > > > >rs[0-9] 200 > >rs1[0-9] 50 > > > >The second group is overloaded, whereas the first group has plenty of > space. > > > >We know that we can handle at maximum *2500 regions* (200*10 + 50*10) and > >we have currently *1200 regions* (60*20). HeterogeneousBalancer will > >understand that the cluster is *full at 48.0%* (1200/2500). Based on this > >information, we will then *try to put all the RegionServers to ~48% of > load > >according to the rules.* In this case, it will move regions from the > second > >group to the first. > > > >The balancer will: > > > > - compute how many regions needs to be moved. In our example, by moving > > 36 regions on rs10, we could go from 120.0% to 46.0% > > - select regions with lowest data-locality > > - try to find an appropriate RS for the region. We will take the lowest > > available RS. > > > >< > https://gist.github.com/PierreZ/15560e12c147e661e5c1b5f0edeb9282#current-status > >Current > >status > > > >We started the implementation, but it is not finished yet. we are planning > >to deploy it on a cluster with lower impact for testing, and then put it > on > >our biggest cluster. > > > >We have some basic implementation of all methods, but we need to add more > >tests and make the code more robust. You can find the proof-of-concept > here > >< > https://github.com/PierreZ/hbase/blob/dev/hbase14/balancer/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/HeterogeneousBalancer.java > >, > >and some early tests here > >< > https://github.com/PierreZ/hbase/blob/dev/hbase14/balancer/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/HeterogeneousBalancer.java > >, > >here > >< > https://github.com/PierreZ/hbase/blob/dev/hbase14/balancer/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestHeterogeneousBalancerBalance.java > >, > >and here > >< > https://github.com/PierreZ/hbase/blob/dev/hbase14/balancer/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestHeterogeneousBalancerRules.java > >. > >We wrote the balancer for our use-case, which means that: > > > > - there is one table > > - there is no region-replica > > - good key dispersion > > - there is no regions on master > > > >However, we believe that this will not be too complicated to implement. We > >are also thinking about the possibility to limit overassigments of regions > >by moving them to the least loaded RS. > > > >Even if the balancing strategy seems simple, we do think that having the > >possibility to run HBase cluster on heterogeneous hardware is vital, > >especially in cloud environment, because you may not be able to buy the > >same server specs throughout the years. > > > >What do you think about our approach? Are you interested for such a > >contribution? > >--- > > > >Pierre ZEMB - OVH Group > >Observability/Metrics - Infrastructure Engineer > >pierrezemb.fr > >+33 7 86 95 61 65 >
