kjaggann edited a comment on issue #572:
URL: https://github.com/apache/pulsar/issues/572#issuecomment-638395246
My understanding zookeeper has an issue in terms of "quorum" and "split
Brain"
my finding correct me if I am wrong lets take we have 5 servers. The voting
to elect the leader is based on the majority of the servers. the number of
servers must accept specific server to become the leader, the other becomes the
followers
So there is this bad thing that may happen called "split brain". A split
brain is simply this, as far as I understand: The cluster of 5 servers splits
into two parts, or let's call it "server teams", with maybe one part of 2 and
the other of 3 servers. This is really a bad situation as if both "server
teams" must execute a specific order how would you decide which team should be
preferred? So it is really important to know what "server team" is still
relevant and which one can/should be ignored.
When one server in {3,4,5} realizes the leader is gone, it triggers an
election. Once a new leader is elected, it starts serving client requests
normally. The other partitioned cluster {1,2} won't serve any client request
and will be stuck in the election until the partition is resolved. So it waits
till the issue resolved and the cluster runs normal again.
Currently, pulsar uses Apache zookeeper to store its metadata. Data such as
the location of partitions and the configuration of topics are stored outside
of pulsar itself, in a separate Zookeeper cluster. so is there a plan to break
this dependency and bring metadata management into Pulsar itself.
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
