simply about difficult
The exception looks like this: We know, that in zookeeper.properties (or zoo.cfg) there is a cluster configuration of the following type: From a certain version of ZooKeeper, it became like this https://zookeeper.apache.org/doc/r3.5.3-beta/zookeeperReconfig.html#ch_reconfig_format: Apache Curator switched to a new format, discontinuing support for the old one. However, ZooKeeper kept it: on the same page in the […]
READ MOREIf 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 MOREIn 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 MORELet’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 MORESuppose that we were trying to call close() on an Apache Curator Framework object, and we encountered this exception: There will also be an answer to the question of how to know if a Curator Framework is running or started. This is happed because the Curator Framework has already been stopped or has not started […]
READ MOREIMPORTANT! 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 MOREIf you came to this page, it means that ZooKeeper began to take up a lot of space, and you need to find the reason. Mostly ephemeral data is stored in ZooKeeper. So at some time you asks the question – why the server began to consume so much disk space? The fact is that […]
READ MOREThe documentation states that setting an ACL via the ZooKeeper CLI usually works like this: In the case of the x509 scheme, the Authenticated ID for the user is the DN string of their certificate. In confirmation of this, when a user connects via a certificate, there is a line in the server log: Now, […]
READ MOREThe exception looks like this: This is because the CN (Common Name) field of the certificate must match the hostname where the certificate will be installed. If it is problematic to reissue certificates, you can disable this check for test environments. ZooKeeper Java client There are several ways to configure SSL, you can learn about […]
READ MOREWe have a ZooKeeper server and a java client application that connects to it. SSL has appeared in ZooKeeper since version 3.5.: https://issues.apache.org/jira/browse/ZOOKEEPER-2125 Server Tuning There are several types of ZooKeeper server distribution. We’ll cover the standalone version as well as the Apache Kafka version. We need a configured server for start. The setup process […]
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