Apache Cassandra VS Apache ZooKeeper

Apache Cassandra

Apache Cassandra{:target="_blank"} is a highly scalable and fault-tolerant database that can handle large volumes of data across multiple nodes or clusters. It provides fast read and write operations, making it suitable for real-time analytics or applications with high throughput requirements.

Wide Column: Apache Cassandra, ScyllaDB and DynamoDB

Cassandra, a replicated, fault-tolerant, decentralized and scalable database system.

A popular database you might already be familiar with is Apache Cassandra®, which powers high-performing applications for thousands of companies including Hulu, Netflix, Spotify, and Apple. While this free, open-source database is known for its high availability, scalability, and resilience; the downside is that it’s also notoriously complex to set up and manage.

In our previous article, we looked at augmenting our dashboard to store and display individual events from the Avengers using DataStax Astra, a serverless DBaaS powered by Apache Cassandra using Stargate to offer additional APIs for working with it.

Example: Apache Cassandra, CouchDB.

For our TikTok database, we’re using DataStax Astra DB: a cloud-based database that fully manages Apache Cassandra®, one of the most robust and scalable NoSQL databases around.

Apache ZooKeeper — a distributed coordination, synchronization, and configuration service (written in Java);

To use Kafka, we also need to deploy a service that keeps configuration informations such as Zookeeper.

Failure Detection and Recovery It’s not enough to have backup systems. It’s also crucial to detect failures quickly. Modern systems employ monitoring tools and rely on distributed coordination systems such as Zookeeper or etcd to identify faults in real-time: once detected, recovery mechanisms are triggered to restore the service.

zookeeper: is (was?) used for secrets management. it was also used as a basic health check, but has been since been replaced.

You can install Kafka from https://kafka.apache.org/quickstart. Because Druid and Kafka both use Apache Zookeeper, I opted to use the Zookeeper deployment that comes with Druid, so didn’t start it with Kafka. Once running, I created two topics for me to post the data into, and for Druid to ingest from:

Please note that we use Zookeeper as the Governance Center.

Next, review deployment complexity such as DB-less versus database-backed deployments. For example, Kong does require running Cassandra or Postgres. Apigee requires Cassandra, Zookeeper, and Postgres to run, while other solutions like Express Gateway and Tyk only require Redis. Apache APISIX uses etcd as its data store, it stores and manages routing-related and plugin-related configurations in etcd in the Data Plane.

ZooKeeper, a system for coordinating distributed nodes, similar to Google's Chubby

[Unit] Description=Apache Zookeeper server Documentation=http://zookeeper.apache.org Requires=network.target remote-fs.target After=network.target remote-fs.target [Service] Type=simple ExecStart=/usr/local/kafka/bin/zookeeper-server-start.sh /usr/local/kafka/config/zookeeper.properties ExecStop=/usr/local/kafka/bin/zookeeper-server-stop.sh Restart=on-abnormal [Install] WantedBy=multi-user.target

ElasticJob achieves distributed coordination through ZooKeeper. In practical scenarios, users may start multiple jobs in the same project simultaneously, all of which use the same Apache Curator client. There are certain risks due to the nature of ZooKeeper and the callback method of Curator in a single event thread.