Is ZooKeeper still use in Cassandra?

[ibrahim El-sanosi <ib...@gmail.com>]

Hi folks,

I read Cassandra white paper, I come across a text says "Cassandra system
elects a leader amongst its nodes using a system called Zookeeper[13]. All
nodes on joining the cluster contact the leader who tells them for what
ranges they are replicas for and leader makes a concerted effort to
maintain the invariant that no node is responsible for more than N-1 ranges
in the ring. The metadata about the ranges a node is responsible is cached
locally at each node and in a fault-tolerant manner inside Zookeeper - this
way a node that crashes and comes back up knows what ranges it was
responsible for."

Does Cassandra still use ZooKeeper? if yes can you refer me to any related
article?

Regards,

Ibrahim

Re: Is ZooKeeper still use in Cassandra?

[Utkarsh Sengar <ut...@gmail.com>]

I think he is referring to the original cassandra paper (5.2 Replication):
https://www.cs.cornell.edu/projects/ladis2009/papers/lakshman-ladis2009.pdf

@Ibrahim Check this post by datastax: 5.2 Replication:
http://docs.datastax.com/en/articles/cassandra/cassandrathenandnow.html
"Zookeeper usage was restricted to Facebook’s in-house Cassandra branch;
Apache Cassandra has always avoided it. This means that you can’t add nodes
to the cluster faster than membership awareness can spread via gossip (up
to a minute for a large cluster), but we consider this worth the simplicity
of avoiding the extra moving parts."

On Sun, Aug 30, 2015 at 2:30 PM, Sebastian Estevez <
sebastian.estevez@datastax.com> wrote:

> No it does not. Where are you reading this?
> On Aug 30, 2015 5:09 PM, "ibrahim El-sanosi" <ib...@gmail.com>
> wrote:
>
>> Hi folks,
>>
>> I read Cassandra white paper, I come across a text says "Cassandra system
>> elects a leader amongst its nodes using a system called Zookeeper[13]. All
>> nodes on joining the cluster contact the leader who tells them for what
>> ranges they are replicas for and leader makes a concerted effort to
>> maintain the invariant that no node is responsible for more than N-1 ranges
>> in the ring. The metadata about the ranges a node is responsible is cached
>> locally at each node and in a fault-tolerant manner inside Zookeeper - this
>> way a node that crashes and comes back up knows what ranges it was
>> responsible for."
>>
>> Does Cassandra still use ZooKeeper? if yes can you refer me to any
>> related article?
>>
>> Regards,
>>
>> Ibrahim
>>
>


-- 
Thanks,
-Utkarsh

Re: Is ZooKeeper still use in Cassandra?

[Sebastian Estevez <se...@datastax.com>]

No it does not. Where are you reading this?
On Aug 30, 2015 5:09 PM, "ibrahim El-sanosi" <ib...@gmail.com>
wrote:

> Hi folks,
>
> I read Cassandra white paper, I come across a text says "Cassandra system
> elects a leader amongst its nodes using a system called Zookeeper[13]. All
> nodes on joining the cluster contact the leader who tells them for what
> ranges they are replicas for and leader makes a concerted effort to
> maintain the invariant that no node is responsible for more than N-1 ranges
> in the ring. The metadata about the ranges a node is responsible is cached
> locally at each node and in a fault-tolerant manner inside Zookeeper - this
> way a node that crashes and comes back up knows what ranges it was
> responsible for."
>
> Does Cassandra still use ZooKeeper? if yes can you refer me to any related
> article?
>
> Regards,
>
> Ibrahim
>