Hyperledger Fabric Composer & web sandbox Hyperledger Composer is an framework that allows development of Hyperledger fabric based blockchain applications. It must be noted that it has been deprecated with Fabric 1.4 released in August 2019. This is the first long term support release for Hyperledger fabric. It is pledged by maintainers to provide bug… Continue reading »
Apache Flink: could not find implicit value for evidence parameter of type This is a common error when transforming streams in Apache Flink based applications. The solution is simple. We just need to import the following: Which should import the necessary types for the operations.
Kafka Connect – Externalizing Secrets – KIP 297 In order to connect with a data source or sink, we need to use credentials. Kafka Connect added support for specifying credential using config providers. The support for file config provider is available with the installation package. This is discussed in KIP 297. The KIP was released… Continue reading »
Kafka Connect Couchbase Connector – Document Expiration Couchbase supports document expiration. If the documents are ingested from Kafka through Couchbase Sink connector the expiration can be set at the connector side where we can set the expiration for each record upserted as document in couchbase. Here is a sample configuration for the connector: Here is… Continue reading »
Securing JMX on Confluent Kafka Confluent kafka process start with these default arguments. You can see that JMX authentication is disabled by default. This is a security vulnerability and might lead to possible issues. Confluent kafka consists of the following services. We need to enable authentication for all of these services for JMX: Kafka Broker… Continue reading »
Kafka Tools – kafkacat – non-JVM Kafka producer / consumer kafkacat is an amazing kafka tool based on librdkafka library, which is a C/C++ library for kafka. It means that it doesn’t have dependency on JVM to work with kafka data as administrator. It can be used to consume and produce messages from kafka topics…. Continue reading »
Kafka Tools – kafka-delete-records While working with kafka we, sometimes, need to purge records from a topic. This is specially needed in a development environment where we just want to get rid of some records and want to keep the other ones. Previously we have discussed how we can purge all records from a topic… Continue reading »
Apache Flink: History Server One of the problems we have faced running Apache Flink that we have a very limited windows for getting access to the details about failed / crashed jobs. The job details just disappear and cannot be retrieved especially form web front end. Here is how it looks like: Actually we are… Continue reading »
Confluent Hub Client Confluent Hub is an online repository for extensions and components for Kafka. Kafka is based on extensible model for many of its services. It allows plug-ins and extensions which makes it generic enough to be suitable for many real world streaming based applications. They include both Confluent and 3rd party components. Generally,… Continue reading »
Issues with Running Elasticseach from Command Line on Linux – bootstrap checks failed I ran into some issues running Elasticsearch on Linux. The issues and solutions might be of some use for others. vm.max_map_count [65530] is too low If you are getting the following error: Then you can resolve it by increasing the max_map_count to… Continue reading »