Apache ZooKeeper is a core infrastructure component in Apache Hadoop stack and is also widely used by many companies for service discovery, configuration management, and so on. Previously ZooKeeper does not support authentication and authorization of servers that are participating in the leader election and quorum forming process; ZooKeeper assumes that every server that is listed in the ZooKeeper configuration file (zoo.cfg) is authenticated. As a result, a server listed in zoo.cfg can join the ensemble even if it is compromised,
Thanks to Karthik Vadla, Abhi Basu, and Monica Martinez-Canales of Intel Corp. for the following guest post about using CDH for cost-effective processing/indexing of DICOM (medical) images.
Medical imaging has rapidly become the best non-invasive method to evaluate a patient and determine whether a medical condition exists. Imaging is used to assist in the diagnosis of a condition and, in most cases, is the first step of the journey through the modern medical system.
The guest post below was originally authored by Pinterest engineer Raghavendra Prabhu and published by the Pinterest Engineering blog. Being big ZooKeeper fans, we re-publish it here for your convenience. Thanks, Pinterest!
Apache ZooKeeper is an open source distributed coordination service that’s popular for use cases like service discovery, dynamic configuration management and distributed locking. While it’s versatile and useful, it has failure modes that can be hard to prepare for and recover from,
Flavio Junqueira (PMC Chair of the Apache ZooKeeper project and a member of the Systems and Networking Group at Microsoft Research) and Benjamin Reed (PMC Member and Software Engineer at Facebook) are the co-authors of the new O’Reilly Media book ZooKeeper: Distributed Process Coordination. We had a chat with Flavio and Ben recently about the rationale for writing the book, and what it will add to the distributed systems conversation.
Apache ZooKeeper is a client/server system for distributed coordination that exposes an interface similar to a filesystem, where each node (called a znode) may contain data and a set of children. Each znode has a name and can be identified using a filesystem-like path (for example, /root-znode/sub-znode/my-znode).
In Apache HBase, ZooKeeper coordinates, communicates, and shares state between the Masters and RegionServers. HBase has a design policy of using ZooKeeper only for transient data (that is,