Seems Clay's idea is also a very good idea. that would also make impl much simpler and the focus would only be on cost functions.
Regards Ram On Fri, Jun 21, 2019 at 10:21 AM Anoop John <[email protected]> wrote: > Same Q as Clay asked. We can see.. > > Also generically we can not consider like only one table in cluster. At > top level we give options like balance per table level or per cluster level > only. This also should be considered for the new balancer also IMO. Ya if > it can work with cost function change alone, it will be much smaller > change. On high level am +1 for such a simple way to handle the > heterogeneous nodes cluster. > > Anoop > > On Fri, Jun 21, 2019 at 5:15 AM Clay Baenziger (BLOOMBERG/ 731 LEX) < > [email protected]> wrote: > > > Could it work to have the stochastic load balancer use pluggable cost > > functions[1]? Then, could this type of a load balancer be implemented > > simply as a new cost function which folks could choose to load and mix > with > > the others? > > > > -Clay > > > > [1]: Instead of this static list of cost functions? > > > https://github.com/apache/hbase/blob/baf3ae80f5588ee848176adefc9f56818458a387/hbase-server/src/main/java/org/apache/hadoop/hbase/master/balancer/StochasticLoadBalancer.java#L198 > > > > From: [email protected] At: 06/20/19 12:54:23To: > [email protected] > > Subject: Re: Adding a new balancer to HBase > > > > Bonjour Pierre, > > > > Some time ago I build (for my own purposes) something similar that I > called > > "LoadBasedLoadBalancer" that moves the regions based on my servers load > and > > capacity. The load balancer is querying the region servers to get the > > number of cores, the allocated heap, the 5 minutes average load, etc. and > > balanced the regions based on that. > > > > I felt that need already years ago. What you are proposing is a > simplified > > version that will most probably be more stable and easier to implement. I > > will be happy to assist you in the process or getting that into HBase. > > > > Have you already opened the JIRA to support that? > > > > Thanks, > > > > JMS > > > > Le jeu. 20 juin 2019 à 01:11, ramkrishna vasudevan < > > [email protected]> a écrit : > > > > > 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-wor > > ks > > > > >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 > > < > 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 > > < > 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.j > > < > https://github.com/PierreZ/hbase/blob/dev/hbase14/balancer/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestHeterogeneousBalancerBalance.j > > > > ava > > > > >, > > > > >and here > > > > >< > > > > > > > > > > > > https://github.com/PierreZ/hbase/blob/dev/hbase14/balancer/hbase-server/src/test > > > > > /java/org/apache/hadoop/hbase/master/balancer/TestHeterogeneousBalancerRules.jav > > < > https://github.com/PierreZ/hbase/blob/dev/hbase14/balancer/hbase-server/src/test/java/org/apache/hadoop/hbase/master/balancer/TestHeterogeneousBalancerRules.jav > > > > a > > > > >. > > > > >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 > > > > > > > > > > > > > >
