tendermint VS Apache ZooKeeper

Tendermint Core / CometBFT — a state machine replication engine (written in Go);

There are good use-cases, but to much focus on cryptocurrencies. Frameworks are not well designed to be used in other use-cases. Best that I have found that doesn't forces you to a specific architecture is Tendermint, but is not even close to state-of-the-art performance and scalability. Everything else is designed around cryptocurrency and smart contracts.

BFT is an algorithm that ensures that the whole network works well even if a few members are acting fraudulently. As long as these fraudulent members are less than 33% of those who have voting power, the network will work fine. Those with voting power are those with something at stake. Cosmos uses a type of BFT consensus engine known as Tendermint. Cosmos uses Tendermint because it provides the best support for building POS blockchains.

Relevant Github ticket showing chains are now scrambling to decide which fork to use: https://github.com/tendermint/tendermint/issues/9972

BlockX is based on Tendermint Core, which relies on a set of validators that are responsible for committing new blocks in the blockchain. These validators participate in the consensus protocol by broadcasting votes which contain cryptographic signatures signed by each validator's private key.

Built with Cosmos and Tendermint.

Haqq is a scalable, high-throughput Proof-of-Stake blockchain that is fully compatible and interoperable with Ethereum. It's built using the Cosmos SDK which runs on top of Tendermint Core consensus engine.Haqq allows for running vanilla Ethereum as a Cosmos application-specific blockchain. This allows developers to have all the desired features of Ethereum, while at the same time, benefit from Tendermint’s PoS implementation. Also, because it is built on top of the Cosmos SDK, it will be able to exchange value with the rest of the Cosmos Ecosystem through the Inter Blockchain Communication Protocol (IBC)Features

Tendermint

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.