ZooKeeper recursive watcher

If you need to set up a recursive watchers (watch on all nodes), the standard ZooKeeper’s Watcher class will not help much – it is installed on only 1 node (or one-level-forward when you calling getChildren()), and is also a one-time event. This means that after each watch trigger, you need to install a new […]

READ MORE

How ZooKeeper ACL works

In this post I will describe the basic principles of how ACL works in ZooKeeper. ACL is not set recursively and is not inherited by the child nodes. If we have a read-only ACL for /path1/path2 or /path1/path2/path3, then deleting /path1 will fail, regardless of AСL of /path1. Several ACL records can be set on […]

READ MORE

Apache Atlas – Building & Installing

Let’s say we want to got working Apache Atlas instance with embedded Hbase & Solr on our machine. Notice, that you need to install JDK 8 before start. Go to the Apache Atlas GitHub page, and download the zip file with the source code of the latest stable release from here: https://github.com/apache/atlas/tags Important notice: DO […]

READ MORE

How to immediately terminate the Spring Boot Yarn container with an error

Imagine an error or exception occurs while running the Spring Boot Yarn container, and we need to kill container from itself and return an error code. You can use @OnContainerStart annotation as mentioned in this article: https://mchesnavsky.tech/how-to-set-up-exit-code-on-spring-boot-yarn-container. But if we need to stop the container immediately, we just need to call: – where parameter is […]

READ MORE

KeeperErrorCode = ConnectionLoss for /hbase/hbaseid

IMPORTANT! If you trying to install Apache Atlas and receiving this error, there is a separate article: https://mchesnavsky.tech/apache-atlas-building-installing/ Suppose that we are faced with these exceptions. The first: The second: The third: The hbase-client cannot connect to the Zookeeper. You need to pay attention to the address: If there is a real Zookeeper instance at […]

READ MORE

IgniteException: Work directory does not exist

Suppose that when starting the application, you encounter the following exception: It is assumed, that the /tmp/ignite/work directory is located on the local file system. If the application is running on a cluster, then Ignite will try to create such a folder on each node of the cluster. Exception reasons: The account under which the […]

READ MORE

Spring Boot Yarn onContainerFailed method diagnostics message

Suppose that we have an SBY application, which includes AppMaster and Container. When the container falls due to an exception, we need to send exception text to the AppMaster. When the container falls, the AppMaster’s onContainerFailed() method is automatically called: The method is in the StaticEventingAppmaster class. Your AppMaster must be inherited from it. We […]

READ MORE