On 04/30/2010 10:16 AM, Aaron Crow wrote:
Hi Patrick, thanks for your time and detailed questions.
No worries. When we hear about an issue we're very interested to
followup and resolve it, regardless of the source. We take the project
goals of high reliability/availablity _very_ seriously,
Hi Lei,
In this case, the Leader will be disconnected from ZK cluster and will give
up its leadership. Since its disconnected, ZK cluster will realize that the
Leader is dead!
When Zk cluster realizes that the Leader is dead (this is because the zk
cluster hasn't heard from the Leader for a
Hi Mahadev,
Why would the leader be disconnected from ZK? ZK is fine communicating with
the leader in this case. We are talking about asymmetric network failure.
Yes. Leader could consider all the slaves being down if it tracks the status
of all slaves himself. But I guess if ZK is used for for
Hi Lei,
Sorry I minsinterpreted your question! The scenario you describe could be
handled in such a way -
You could have a status node in ZooKeeper which every slave will subscribe
to and update! If one of the slave nodes sees that there have been too many
connection refused to the Leader by the
Lei,
I think that Mahadev was correct that there is some confusion here.
Leader election is normally a term used for an operation that is entirely
internal to ZK. It is very robust and you probably don't need to worry
about it.
You can then use ZK in your application to pick a lead machine for
Hi Mahadev,
First of all, I like to thank you for being patient with me - my questions
seem unclear to many of you who try to help me.
I guess clients have to be smart enough to trigger a new leader election by
trying to delete the znode. But in this case, ZK should not allow any single
or
I believe Lei's concern is that the leader and all slaves can talk to
ZK, but the slaves cannot talk to the leader. As a result no work can be
done. However nothing will happen on the ZK side since everyone is
heartbeating properly.
Mahadev I think you came up with a pretty good solution.
HI Lei,
ZooKeeper provides a set of primitives which allows you to do all kinds of
things! You might want to take a look at the api and some examples of
zookeeper recipes to see how it works and probably that will clear things
out for you.
Here are the links:
