Technically, ZK does not support it. However, there is a methodology for reconfiguring and updated an ensemble. I believe ZK-107 will allow the changes to be made without needing to restart/reconfigure the cluster.
-JZ On 4/30/12 11:49 AM, "Mohammad Abdul-Amir (Shamma)" <[email protected]> wrote: >Alex, > >It sounds like you are suggesting that zookeeper keeper does not support >adding/removing servers non-dynamically. If so, this contradicts with the >FAQ #6 that Jordan Zimmerman pointed out. > >On Sun, Apr 29, 2012 at 11:32 PM, Alexander Shraer ><[email protected]>wrote: > >> Hi Mohammad, >> >> Support for adding/removing servers as well as dynamic changes to >> other parameters will be added as part of ZOOKEEPER-107, hopefully in >> the 3.5.0 release. >> >> Thanks, >> Alex >> >> On Thu, Apr 26, 2012 at 3:55 PM, Mohammad Abdul-Amir (Shamma) >> <[email protected]> wrote: >> > On Thu, Apr 26, 2012 at 2:48 PM, Jordan Zimmerman < >> [email protected]>wrote: >> > >> >> See #6 in the FAQ: http://wiki.apache.org/hadoop/ZooKeeper/FAQ >> >> >> >> >> > Okay, it seems that a zookeeper "upgrade" is possible according to >>FAQ. >> > >> > Does removing/decommissioning a zookeeper server fall under the >>notion of >> > "upgrade" though? Does "upgrade" apply to any zookeeper config update? >> > >> > >> >> Also, FYI, we recently open sourced a ZooKeeper supervisor app that >> makes >> >> these kinds of tasks simpler: >> >> >> >> https://github.com/Netflix/exhibitor >> >> >> >> -Jordan >> >> >> >> On 4/26/12 2:46 PM, "Mohammad Abdul-Amir (Shamma)" >> >> <[email protected]> wrote: >> >> >> >> >Hello, >> >> > >> >> >I have been searching through the zookeeper documentation and the >>web >> for >> >> >information about reconfiguring a zookeeper ensemble. More >>precisely I >> am >> >> >interested in adding/removing zookeeper servers to/from a zookeeper >> >> >ensemble. Unfortunately, I could not find much information around, >> >> >therefore I am bringing up the issue on this list. >> >> > >> >> >My questions are: >> >> > >> >> >- Is there a safe procedure to add a zookeeper server to a zookeeper >> >> >ensemble? >> >> >- Is there a safe procedure to remove a zookeeper server from an >> existing >> >> >ensemble? >> >> > >> >> >Some posts I have read suggest that these operations are possible. >>The >> >> >described procedure is to rewrite a new zookeeper configuration to >>all >> >> >involved servers and to restart them. However, given that I could >>not >> find >> >> >any information about how to carry out these two operations in >> zookeeper's >> >> >documentation makes me nervous about relying on the described >> procedure. >> >> > >> >> >I would appreciate if anyone can point me to a different procedures >>to >> >> >carry out add/remove operations, or convince me that it is safe to >>use >> the >> >> >procedure described above. Safety for me is two-fold: zookeeper >> database >> >> >can not get corrupted (unusable), and state updates can not get >>lost. >> >> > >> >> >-- >> >> >Mohammad Abdul-Amir (Shamma) >> >> >> >> >> > >> > >> > -- >> > Mohammad Abdul-Amir (Shamma) >> > > > >-- >Mohammad Abdul-Amir (Shamma)
