zookeeper | The learning process of distributed system service ZooKeeper | Messaging library

 by   llohellohe Java Version: Current License: No License

kandi X-RAY | zookeeper Summary

kandi X-RAY | zookeeper Summary

zookeeper is a Java library typically used in Messaging, MongoDB, Kafka, RabbitMQ applications. zookeeper has no bugs, it has no vulnerabilities, it has build file available and it has medium support. You can download it from GitHub.

The learning process of distributed system service ZooKeeper
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    Quality
      Security
        License
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            kandi-support Support

              zookeeper has a medium active ecosystem.
              It has 1161 star(s) with 503 fork(s). There are 121 watchers for this library.
              OutlinedDot
              It had no major release in the last 6 months.
              There are 6 open issues and 0 have been closed. On average issues are closed in 1060 days. There are 1 open pull requests and 0 closed requests.
              It has a neutral sentiment in the developer community.
              The latest version of zookeeper is current.

            kandi-Quality Quality

              zookeeper has 0 bugs and 0 code smells.

            kandi-Security Security

              zookeeper has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
              zookeeper code analysis shows 0 unresolved vulnerabilities.
              There are 0 security hotspots that need review.

            kandi-License License

              zookeeper does not have a standard license declared.
              Check the repository for any license declaration and review the terms closely.
              OutlinedDot
              Without a license, all rights are reserved, and you cannot use the library in your applications.

            kandi-Reuse Reuse

              zookeeper releases are not available. You will need to build from source code and install.
              Build file is available. You can build the component from source.
              zookeeper saves you 279 person hours of effort in developing the same functionality from scratch.
              It has 675 lines of code, 45 functions and 12 files.
              It has medium code complexity. Code complexity directly impacts maintainability of the code.

            Top functions reviewed by kandi - BETA

            kandi has reviewed zookeeper and discovered the below as its top functions. This is intended to give you an instant insight into zookeeper implemented functionality, and help decide if they suit your requirements.
            • Runs the leader
            • Checks if there is a master node
            • Create master node
            • Sleep for given seconds
            • Test program
            • Run the daemon
            • Process an event
            • Process a WatchedEvent
            • Process result
            • Main entry point
            • Checks if the given data exists
            • Main method
            • Test entry point
            • Close all resources
            • The main entry point
            Get all kandi verified functions for this library.

            zookeeper Key Features

            No Key Features are available at this moment for zookeeper.

            zookeeper Examples and Code Snippets

            Initialize Zookeeper connection .
            javadot img1Lines of Code : 8dot img1License : Permissive (MIT License)
            copy iconCopy
            private void initialize() {
                    try {
                        zkConnection = new ZKConnection();
                        zkeeper = zkConnection.connect("localhost");
                    } catch (Exception e) {
                        System.out.println(e.getMessage());
                    }
                }  
            Update data in ZooKeeper
            javadot img2Lines of Code : 5dot img2License : Permissive (MIT License)
            copy iconCopy
            public void update(String path, byte[] data) throws KeeperException, InterruptedException {
                    int version = zkeeper.exists(path, true)
                        .getVersion();
                    zkeeper.setData(path, data, version);
                }  
            Close ZooKeeper .
            javadot img3Lines of Code : 3dot img3License : Permissive (MIT License)
            copy iconCopy
            public void close() throws InterruptedException {
                    zoo.close();
                }  

            Community Discussions

            QUESTION

            Kafka consumer does not print anything
            Asked 2022-Mar-26 at 12:23

            I am following this tutorial: https://towardsdatascience.com/kafka-docker-python-408baf0e1088 in order to run a producer-consumer example using Kafka, Docker and Python. My problem is that my terminal prints the iterations of the producer, while it does not print the iterations of consumer. I am running this example in local, so:

            1. in one terminal tab I have done: docker-compose -f docker-compose-expose.yml up where my docker-compose-expose.yml is this:
            ...

            ANSWER

            Answered 2022-Mar-26 at 12:23

            Basically I had understood that the problem was in some images/processes that were in execution. With docker-compose stop and docker-compose rm -f I solved.

            Source https://stackoverflow.com/questions/71572487

            QUESTION

            EmbeddedKafka failing since Spring Boot 2.6.X : AccessDeniedException: ..\AppData\Local\Temp\spring.kafka*
            Asked 2022-Mar-25 at 12:39

            e: this has been fixed through Spring Boot 2.6.5 (see https://github.com/spring-projects/spring-boot/issues/30243)

            Since upgrading to Spring Boot 2.6.X (in my case: 2.6.1), I have multiple projects that now have failing unit-tests on Windows that cannot start EmbeddedKafka, that do run with Linux

            There is multiple errors, but this is the first one thrown

            ...

            ANSWER

            Answered 2021-Dec-09 at 15:51

            Known bug on the Apache Kafka side. Nothing to do from Spring perspective. See more info here: https://github.com/spring-projects/spring-kafka/discussions/2027. And here: https://issues.apache.org/jira/browse/KAFKA-13391

            You need to wait until Apache Kafka 3.0.1 or don't use embedded Kafka and just rely on the Testcontainers, for example, or fully external Apache Kafka broker.

            Source https://stackoverflow.com/questions/70292425

            QUESTION

            Exception in thread "main" joptsimple.UnrecognizedOptionException: zookeeper is not a recognized option
            Asked 2022-Mar-24 at 12:28

            I am new to kafka and zookepper, and I am trying to create a topic, but I am getting this error -

            ...

            ANSWER

            Answered 2021-Sep-30 at 14:52

            Read the official Kafka documentation for the version you downloaded, and not some other blog/article that you might have copied the command from

            zookeeper is almost never used for CLI commands in current versions

            If you run bin\kafka-topics on its own with --help or no options, then it'll print the help messaging that shows all available arguments.

            Source https://stackoverflow.com/questions/69297020

            QUESTION

            Define Kafka ACL to limit topic creation
            Asked 2021-Dec-30 at 07:35

            We are currently running an unsecured Kafka setup on AWS MSK (so I don't have access to most config files directly and need to use the kafka-cli) and are looking into ways to add protection. Setting up TLS & SASL is easy, though as our Kafka cluster is behind a VPN and already has restricted access does not add more security.

            We want to start with the most important and in our opinion quick win security addition. Protect topics from being deleted (and created) by all users. We currently have allow.everyone.if.no.acl.found set to true.

            All I find on Google or Stack Overflow shows me how I can restrict users from reading/writing to other topics than they have access to. Though Ideally that is not what we want to implement as a first step.

            I have found things about a root-user (Is an admin user, though was called root in all tutorials I read). Though the examples I have found don't show examples of adding an ACL to this root user to make it the only one accessible, the topic deletion/creation.

            Can you please explain how to create a user that, and block all other users?

            By the way, we also don't use zookeeper, even though an MSK-cluster ads this per default. And hope we can do this without adding zookeeper actively to our stack. The answer given here hardly relies on zookeeper. Also, this answer points to the topic read/write examples only, even though the question was the same as I am asking

            ...

            ANSWER

            Answered 2021-Dec-21 at 10:11

            I'd like to start with a disclaimer that I'm personally not familiar with AWS MSK offering in great detail so this answer is largely based on my understanding of the open source distribution of Apache Kafka.

            First - The Kafka ACLs are actually stored in Zookeeper by default so if you're not using Zookeeper, it might be worth adding this if you're not using it.

            Reference - Kafka Definitive Guide - 2nd edition - Chapter 11 - Securing Kafka - Page 294

            Second - If you're using SASL for authentication through any of the supported mechanisms such as GSSAPI (Kerberos), then you'll need to create a principal as you would normally create one and use one of the following options:

            1. Add the required permissions for topic creation/deletion etc. using the kafka-acls command (Command Reference)

              bin/kafka-acls.sh --add --cluster --operation Create --authorizer-properties zookeeper.connect=localhost:2181 --allow-principal User:admin

              Note - admin is the assumed principal name

            2. Or add admin user to the super users list in server.properties file by adding the following line so it has unrestricted access on all resources

              super.users=User:Admin

              Any more users can be added in the same line delimited by ;.

            To add the strictness, you'll need to set allow.everyone.if.no.acl.found to false so any access to any resources is only granted by explicitly adding these permissions.

            Third - As you've asked specifically about your root user, I'm assuming you're referring to the linux root here. You could just restrict the linux level permissions using chmod command for the kafka-acls.sh script but that is quite a crude way of achieving what you need. I'm also not entirely sure if this is doable in MSK or not.

            Source https://stackoverflow.com/questions/70409488

            QUESTION

            Migrating from FlinkKafkaConsumer to KafkaSource, no windows executed
            Asked 2021-Nov-30 at 05:29

            I am a kafka and flink beginner. I have implemented FlinkKafkaConsumer to consume messages from a kafka-topic. The only custom setting other than "group" and "topic" is (ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest") to enable re-reading the same messages several times. It works out of the box for consuming and logic. Now FlinkKafkaConsumer is deprecated, and i wanted to change to the successor KafkaSource.

            Initializing KafkaSource with the same parameters as i do FlinkKafkaConsumer produces a read of the topic as expected, i can verify this by printing the stream. De-serialization and timestamps seem to work fine. However execution of windows are not done, and as such no results are produced.

            I assume some default setting(s) in KafkaSource are different from that of FlinkKafkaConsumer, but i have no idea what they might be.

            KafkaSource - Not working

            ...

            ANSWER

            Answered 2021-Nov-24 at 18:39

            Update: The answer is that the KafkaSource behaves differently than FlinkKafkaConsumer in the case where the number of Kafka partitions is smaller than the parallelism of Flink's kafka source operator. See https://stackoverflow.com/a/70101290/2000823 for details.

            Original answer:

            The problem is almost certainly something related to the timestamps and watermarks.

            To verify that timestamps and watermarks are the problem, you could do a quick experiment where you replace the 3-hour-long event time sliding windows with short processing time tumbling windows.

            In general it is preferred (but not required) to have the KafkaSource do the watermarking. Using forMonotonousTimestamps in a watermark generator applied after the source, as you are doing now, is a risky move. This will only work correctly if the timestamps in all of the partitions being consumed by each parallel instance of the source are processed in order. If more than one Kafka partition is assigned to any of the KafkaSource tasks, this isn't going to happen. On the other hand, if you supply the forMonotonousTimestamps watermarking strategy in the fromSource call (rather than noWatermarks), then all that will be required is that the timestamps be in order on a per-partition basis, which I imagine is the case.

            As troubling as that is, it's probably not enough to explain why the windows don't produce any results. Another possible root cause is that the test data set doesn't include any events with timestamps after the first window, so that window never closes.

            Do you have a sink? If not, that would explain things.

            You can use the Flink dashboard to help debug this. Look to see if the watermarks are advancing in the window tasks. Turn on checkpointing, and then look to see how much state the window task has -- it should have some non-zero amount of state.

            Source https://stackoverflow.com/questions/69765972

            QUESTION

            Kafka integration tests in Gradle runs into GitHub Actions
            Asked 2021-Nov-03 at 19:11

            We've been moving our applications from CircleCI to GitHub Actions in our company and we got stuck with a strange situation.

            There has been no change to the project's code, but our kafka integration tests started to fail in GH Actions machines. Everything works fine in CircleCI and locally (MacOS and Fedora linux machines).

            Both CircleCI and GH Actions machines are running Ubuntu (tested versions were 18.04 and 20.04). MacOS was not tested in GH Actions as it doesn't have Docker in it.

            Here are the docker-compose and workflow files used by the build and integration tests:

            • docker-compose.yml
            ...

            ANSWER

            Answered 2021-Nov-03 at 19:11

            We identified some test sequence dependency between the Kafka tests.

            We updated our Gradle version to 7.3-rc-3 which has a more deterministic approach to test scanning. This update "solved" our problem while we prepare to fix the tests' dependencies.

            Source https://stackoverflow.com/questions/69284830

            QUESTION

            Accessing HBase on Amazon EMR with Athena
            Asked 2021-Sep-10 at 08:52

            Has anyone managed to access HBase running as a service on Amazon EMR cluster with Athena? I'm trying to establish a connection to the HBase instance, but the lambda (provided with Athena java function) fails with the following error:

            ...

            ANSWER

            Answered 2021-Sep-10 at 08:52

            Finally, the solution for the issue is to create appropriate dns records for each cluster ec2 instance with the necessary names inside Amazon Route53 service.

            Source https://stackoverflow.com/questions/68996906

            QUESTION

            bash + how to capture word from a long output
            Asked 2021-Sep-03 at 07:02

            I have the following output from the following command

            ...

            ANSWER

            Answered 2021-Sep-02 at 17:28

            With your shown samples, attempts please try following awk code. Since I don't have zookeeper command with me, I had written this code and tested it as per your shown output only.

            Source https://stackoverflow.com/questions/69034663

            QUESTION

            Cannot connect to kafka from ourside of its docker container
            Asked 2021-Aug-30 at 00:40

            This is my docker compose file:

            ...

            ANSWER

            Answered 2021-Aug-30 at 00:39

            You've forwarded the wrong port

            9093 on the host needs to map to the localhost:9093 advertised port

            Otherwise, you're connecting to 9093, which returns kafka:9092, as explained in the blog. Container hostnames cannot be resolved by the host, by default

            Source https://stackoverflow.com/questions/68975387

            QUESTION

            resolve service hostname in ECS fargate task
            Asked 2021-Aug-22 at 20:28

            I am trying to automate my ECS fargate cluster making using terraform.

            I have a SpringBoot project with microservices containerized, and I am putting these images in a single task definition for an ECS service for the backend.

            The ECS cluster is initially running, but Kafka is getting stopped with the error :

            ...

            ANSWER

            Answered 2021-Aug-22 at 17:28

            AS written in the documentation:

            Additionally, containers that belong to the same task can communicate over the localhost interface.

            So my suggestion is to use localhost instead of the service names. For example, you want to do it for Kafka but also for every other service, such as the email service.

            Source https://stackoverflow.com/questions/68880004

            Community Discussions, Code Snippets contain sources that include Stack Exchange Network

            Vulnerabilities

            An issue is present in Apache ZooKeeper 1.0.0 to 3.4.13 and 3.5.0-alpha to 3.5.4-beta. ZooKeeper’s getACL() command doesn’t check any permission when retrieves the ACLs of the requested node and returns all information contained in the ACL Id field as plaintext string. DigestAuthenticationProvider overloads the Id field with the hash value that is used for user authentication. As a consequence, if Digest Authentication is in use, the unsalted hash value will be disclosed by getACL() request for unauthenticated or unprivileged users.

            Install zookeeper

            You can download it from GitHub.
            You can use zookeeper like any standard Java library. Please include the the jar files in your classpath. You can also use any IDE and you can run and debug the zookeeper component as you would do with any other Java program. Best practice is to use a build tool that supports dependency management such as Maven or Gradle. For Maven installation, please refer maven.apache.org. For Gradle installation, please refer gradle.org .

            Support

            For any new features, suggestions and bugs create an issue on GitHub. If you have any questions check and ask questions on community page Stack Overflow .
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