Skip to content

Latest commit

 

History

History
61 lines (56 loc) · 1.82 KB

ZooKeeperObservers.md

File metadata and controls

61 lines (56 loc) · 1.82 KB
Raw

ZooKeeper Observers

Observers: Scaling ZooKeeper Without Hurting Write Performance

  • Observers are non-voting members of an ensemble which only hear the results of votes, not the agreement protocol that leads up to them.
  • Therefore they can fail, or be disconnected from the cluster, without harming the availability of the ZooKeeper service.

How to use Observers

Firstly, in the config file of every node that is to be an Observer, you must place this line:

peerType=observer

Secondly, in every server config file, you must add :observer to the server definition line of each Observer. For example:

server.1:localhost:2181:3181:observer

This tells every other server that server.1 is an Observer, and that they should not expect it to vote.

$ bin/zkCli.sh -server localhost:2181

Example use cases

  • As a datacenter bridge
  • As a link to a message bus

Tips

zookeeper-3.4.10-observer/
├── conf/
│    ├── java.env
│    ├── zoo-2181.cfg
│    ├── zoo-2182.cfg
│    ├── zoo-2183.cfg
│    └── zoo-2188.cfg
├── data-2181/
│    └── myid
├── data-2182/
│    └── myid
├── data-2183/
│    └── myid
├── data-2188/
│    └── myid
├── logs-2181
├── logs-2182
├── logs-2183
└── logs-2188

cd /usr/local/zookeeper-3.4.10-observer
bin/zkServer.sh start conf/zoo-2181.cfg
bin/zkServer.sh start conf/zoo-2182.cfg
bin/zkServer.sh start conf/zoo-2183.cfg
bin/zkServer.sh start conf/zoo-2188.cfg
bin/zkServer.sh status conf/zoo-2181.cfg
bin/zkServer.sh status conf/zoo-2182.cfg
bin/zkServer.sh status conf/zoo-2183.cfg
bin/zkServer.sh status conf/zoo-2188.cfg
bin/zkCli.sh -server localhost:2188

References