What is Apache Zookeeper? | Expert’s Top Picks | Free Guide Tutorial

• In this article you will get
• 1.What is Zookeeper?
• 2.How does Zookeeper work?
• 3.Architecture comprised of ensemble server, server leader follower, and client zookeeper
• 4.What is the purpose of using apache zookeeper?
• 5.What are the benefits of using Zookeeper with Apache Kafka?
• 6.Advantages of utilizing zookeeper
• 7.Design goals
• 8.Disadvantages

What is Zookeeper?

Zookeeper is a top-level programme that was created by Apache. It functions as a centralised service and is used to preserve name and configuration data inside distributed systems. It also provides flexible and resilient synchronisation for these systems. The state of the Kafka cluster nodes is one of the things that Zookeeper monitors. Additionally, it monitors Kafka topics, partitions, and so on.

Zookeeper itself functions as a shared configuration service inside the system and enables numerous clients to execute simultaneous reads and writes. Zookeeper also stores configuration information. The Zookeeper atomic broadcast (ZAB) protocol is the “brains” of the whole system. It is this protocol that enables Zookeeper to function as an atomic broadcast system and to provide updates in an orderly fashion.

How does Zookeeper work?

The data that is stored inside Zookeeper is distributed among a large number of different nodes; this is how the system maintains its high level of availability and consistency. Zookeeper is able to carry out immediate failover migration in the event that a node fails; for instance, if a leader node fails, a replacement one will be chosen in real-time via polling within an ensemble. If the initial node does not answer to a client’s query, the client’s connection to the server may be changed to a new node.

Architecture of the Apache Zookeeper server. The Client-Server Architecture is the one that Zookeeper uses. The architecture known as Zookeeper is comprised of five distinct components, which are as follows:

Architecture Comprised of Ensemble Server, Server Leader Follower, and Client Zookeeper

1. Ensemble: The collection of all of the Server nodes that make up the Zookeeper ecosystem is known as Ensemble. In order to construct an ensemble, there must be a minimum of three nodes.

2. Server : The Zookeeper Ensemble has many nodes, and one of those nodes is named Server. The provision of each and every service requested by a client is the primary purpose of the Server. The Server notifies the client that it is alive by transmitting its alive status to the client in order to let the client know that it is available.

3. Server Leader:The server node that has access to retrieve data from failing nodes is known as the Server/Ensemble Leader. It is in charge of automatically recovering lost data for the customers of the company. It is chosen when the service is first started.

4. The Adherent:One of the server nodes in the Ensemble is referred as as a follower. It acts in accordance with the instructions provided by the Leader.

5. Client: Within a distributed system, the nodes that make service requests to the server are referred to as clients. The clients are the ones that transmit the signals to the servers to let them know that they are available. In the event that the server is unable to reply, the clients will immediately reroute themselves to the next accessible server.

What is the purpose of Using Apache ZooKeeper?

Apache ZooKeeper is a service that is utilised by a cluster, which is defined as a collection of nodes, to cooperate with one another and manage shared data using rigorous synchronisation algorithms. ZooKeeper is an example of a distributed application that also offers services that may be used to build distributed applications.

The following is a list of the most common services that ZooKeeper offers:

Naming service: the process of identifying individual nodes inside a cluster by their respective names. It is similar to DNS, however it only applies to nodes.

The most recent and accurate configuration information of the system for a joining node is what is referred to as “configuration management.”

Cluster management includes both the joining and leaving of a node in a cluster, as well as the display of the status of a node in real time.

Election of the Leader Choosing a node to serve as the leader for coordination purposes.

Service for locking and synchronising data, which involves locking the data while it is being modified. When connecting to other distributed applications like Apache HBase, this approach will assist you in the automated recovery from a failed connection.

A highly dependable data registry that maintains data accessibility even if some of the nodes in the network are offline.

Distributed applications provide a number of complicated and difficult-to-solve issues, despite the fact that they also present a number of advantages. The ZooKeeper framework offers a comprehensive solution that may be used to conquer all of the difficulties.

The method of fail-safe synchronisation is used in order to manage race conditions and deadlocks. The inconsistency of the data is another significant problem, which ZooKeeper addresses by introducing atomicity.

What are the benefits of using Zookeeper with Apache Kafka?

Controller election:In a Kafka ecosystem, the controller is one of the most essential broking entities, and it is also tasked with the job of ensuring that the leader-follower connection is preserved throughout all of the partitions. If a node is about to die for whatever reason, it is the duty of the controller to instruct all of the replicas to take on the role of partition leaders so that the tasks that were performed by the partition leaders on the node that is about to fail may be completed. Therefore, a new controller may be chosen anytime a node is removed from the network. Additionally, it is possible to ensure that at any one moment, there is only one controller, and that all of the follower nodes have reached a consensus on this matter.

Organization of Subject Matter:The configuration for each and every one of the topics, including the list of already existing topics, the number of partitions for each topic, the location of all of the replicas, a list of configuration overrides for each and every topic, which node is the preferred leader, and other similar information.

Lists of access privileges:Within Zookeeper, access control lists, commonly known as ACLs, for each of the subjects are also kept up to date.

Participation in the group’s activities: A list of all the brokers that are active at any one time and are a member of the cluster is another thing that Zookeeper is responsible for maintaining.

Advantages of Utilizing ZooKeeper

Advantages of Utilizing ZooKeeper

The advantages of using ZooKeeper are as follows:

Simple distributed coordination process:

A mutual exclusion and cooperative effort between different server processes is what synchronisation is. This method contributes to the configuration management capabilities of Apache HBase.

Ordered Messages:

Serialization is encoding the data in accordance with a predetermined set of guidelines. Check that your programme continues to function normally. This method may be implemented in MapReduce to synchronise the execution of running threads in the queue.

Reliability:

Atomicity means that a data transfer will either succeed entirely or fail completely; there is no such thing as a partial transaction.

Design Goals

ZooKeeper is simple. ZooKeeper provides a shared hierarchical namespace that is structured in a manner that is analogous to that of a conventional file system. This enables remote processes to cooperate with one another. In ZooKeeper terminology, the data registers are referred to as znodes, and they are quite similar to files and directories. The name space is made up of these znodes. As opposed to a regular file system, which is intended for storage, the data for ZooKeeper is maintained in memory. As a result, ZooKeeper is able to achieve high throughput while maintaining low latency figures.

The ZooKeeper implementation prioritises high speed, high availability, and rigorously ordered access above all other considerations. Due to the high level of performance it offers, ZooKeeper is suitable for implementation in large distributed systems. Because of its dependability, it does not represent a single point of failure in the system. Due to the rigorous ordering, it is possible for the client to construct more complex synchronisation primitives.

There are several copies of ZooKeeper. ZooKeeper is designed to be duplicated over a group of hosts, which is referred to as an ensemble, in the same way that the distributed processes it controls are.

Disadvantages of Zookeeper

• When we attempt to add additional Zookeeper Servers, there is a possibility that data may be lost in Zookeeper.
• It does not provide any assistance in the placement of Racks or notice of their existence.
• When a service is set up to run on a virtual network, we are unable to move it over to the networking of the host computer without first doing a complete reinstallation.
• Because reducing the number of pods might lead to unintended data loss, Zookeeper does not let us to reduce the number of pods.
• Messages have a chance of becoming lost in the communication network. For us to be able to retrieve it again, we need a specialised piece of software.
• No migration is permitted for users of the system.
• When the initial deployment of the service is finished, it will no longer accommodate any changing volume needs.
• Due to the enormous number of nodes that are involved, there is a greater potential for many failure sites.