How does ZooKeeper work?
ZooKeeper is simple. ZooKeeper allows distributed processes to coordinate with each other through a shared hierarchal namespace which is organized similarly to a standard file system. The name space consists of data registers – called znodes, in ZooKeeper parlance – and these are similar to files and directories.
Is ZooKeeper distributed?
ZooKeeper is a distributed, open-source coordination service for distributed applications. It exposes a simple set of primitives that distributed applications can build upon to implement higher level services for synchronization, configuration maintenance, and groups and naming.
What happens if ZooKeeper fails?
If one the ZooKeeper nodes fails, the following occurs: Other ZooKeeper nodes detect the failure to respond. A new ZooKeeper leader is elected if the failed node is the current leader. If multiple nodes fail and ZooKeeper loses its quorum, it will drop into read-only mode and reject requests for changes.
What is ZooKeeper explain services ZooKeeper guarantees?
What does a ZooKeeper do list three 3 main services provided by a ZooKeeper?
ZooKeeper is itself a distributed application providing services for writing a distributed application. Naming service − Identifying the nodes in a cluster by name. Leader election − Electing a node as leader for coordination purpose. Locking and synchronization service − Locking the data while modifying it.
What is the role of ZooKeeper in HBase?
ZooKeeper is a high-performance coordination service for distributed applications(like HBase). It exposes common services like naming, configuration management, synchronization, and group services, in a simple interface so you don’t have to write them from scratch.
What if ZooKeeper fails in HBase?
When a Zookeeper client (such as an HBase RegionServer) writes or reads a znode, the operation is atomic. Zookeeper replicates znodes across the ensemble so if servers fail, the znode data is still available as long as a majority quorum of servers is still up and running.
How many machines can zookeeper handle failure?
For example, with four machines ZooKeeper can only handle the failure of a single machine; if two machines fail, the remaining two machines do not constitute a majority. However, with five machines ZooKeeper can handle the failure of two machines.
What makes zookeeper different from other file systems?
Unlike a typical file system, which is designed for storage, ZooKeeper data is kept in-memory, which means ZooKeeper can achieve high throughput and low latency numbers. The ZooKeeper implementation puts a premium on high performance, highly available, strictly ordered access.
What maintenance is required for a zookeeper cluster?
Little long term maintenance is required for a ZooKeeper cluster however you must be aware of the following: The ZooKeeper Data Directory contains files which are a persistent copy of the znodes stored by a particular serving ensemble. These are the snapshot and transactional log files.
What is native client and native server in Zookeeper?
Server is the Java server that runs on the ZooKeeper ensemble nodes. Native Client is a client implemented in C, similar to the Java client, used by applications to connect to a ZooKeeper ensemble. Contrib refers to multiple optional add-on components.