ZooKeeper
ZooKeeper is a centralized service used to maintain configuration information, naming, and provide distributed synchronization and group services. It is essential for managing large distributed systems. ZooKeeper ensures that distributed applications can coordinate with each other efficiently.
What is ZooKeeper
ZooKeeper is a centralized service designed to maintain configuration information, naming, and provide distributed synchronization and group services. It is an open-source project under the Apache Software Foundation and is widely used in distributed systems to manage and coordinate various services.
Originally developed at Yahoo, ZooKeeper has become a critical component in many large-scale distributed systems. It provides a simple interface and a set of primitives that allow distributed applications to coordinate with each other. This coordination is crucial for tasks such as leader election, configuration management, and distributed locking.
ZooKeeper operates on a hierarchical namespace, similar to a file system, where each node (called a znode) can store data and have child nodes. This structure allows for efficient data management and retrieval. ZooKeeper is designed to be highly reliable and can handle the failure of individual nodes without affecting the overall system's performance.
In addition to its core functionalities, ZooKeeper also provides a set of recipes for common distributed coordination tasks, such as barriers, queues, and locks. These recipes simplify the development of distributed applications by providing pre-built solutions for common problems.
Security risk
If port 2181 is open and the ZooKeeper service is running, it could be a target for unauthorized access or attacks. An attacker could potentially disrupt the coordination of distributed systems, leading to service outages or data inconsistencies. It is crucial to secure this port with proper authentication and firewall rules.
In our UFW tutorial you can follow instructions how you can configure UFW to close port 2181. Use StackChanges to monitor if the ZooKeeper port is closed and stays closed. StackChanges will send an alert if port 2181 is open again.