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Troubleshooting
Resolve problems with Teracloud® Streams using the troubleshooting tools provided with the product as well as the resources offered by Teracloud Support.
Known problems and solutions
Use the solutions that are provided to resolve known problems that you might encounter when you work with different components of the product.
ZooKeeper problems and solutions
Use these solutions to resolve the problems that you might encounter with Apache ZooKeeper.
Embedded ZooKeeper fails to start
In a shared file system environment, embedded ZooKeeper can fail to start if it is already running on another resource.

Welcome
Learn about the core capabilities of Teracloud® Streams, its architecture, and key concepts.
Installing
Use this information to install, upgrade, and uninstall the Teracloud® Streams product.
Configuring
Create a basic or an enterprise domain which is a single point for configuring and managing common resources, security, and instances.
Administering
Administer the product by using the Teracloud® Streams graphical user interface, APIs, or the streamtool command-line interface.
Developing
Develop stream applications with the Streams Processing Language (SPL), Java, and Python.
Troubleshooting
Resolve problems with Teracloud® Streams using the troubleshooting tools provided with the product as well as the resources offered by Teracloud Support.
- Before contacting Teracloud® Support
  Review this information before you contact Teracloud® Support. These resources might help you to find possible solutions for your issue, or make your support experience more efficient if you need to contact Teracloud Support.
- Troubleshooting techniques
  Troubleshooting is a systematic approach to solving a problem. The goal of troubleshooting is to determine why something does not work as you expect it to work, and then decide how to resolve the problem.
- Known problems and solutions
  Use the solutions that are provided to resolve known problems that you might encounter when you work with different components of the product.
  - Teracloud® Streams problems and solutions
    Use the solutions that are provided to resolve the problems that you can encounter when you work with Teracloud® Streams.
  - Toolkit problems and solutions
    Use the solutions that are provided to resolve the problems that you can encounter when you work with toolkits in Teracloud® Streams.
  - ZooKeeper problems and solutions
    Use these solutions to resolve the problems that you might encounter with Apache ZooKeeper.
    - ZooKeeper log files, documentation, and other troubleshooting resources
      These resources provide additional assistance and information for resolving problems with ZooKeeper.
    - ZooKeeper ensemble fails to start
      ZooKeeper might fail to start if the ZooKeeper ensemble is not configured correctly, or there are problems with file permissions, port conflicts, or disk corruption.
    - Embedded ZooKeeper fails to start
      In a shared file system environment, embedded ZooKeeper can fail to start if it is already running on another resource.
    - Embedded ZooKeeper fails to stop
      If you cannot stop the embedded ZooKeeper, you can force the processes to stop.
    - Unable to connect to the ZooKeeper ensemble
      You might not be able to connect to the ZooKeeper ensemble if you exceeded the maximum number of connections, or there are network, host, or ZooKeeper problems.
    - Clients disconnect from the ZooKeeper ensemble
      Clients, such as Teracloud® Streams interfaces and services, might disconnect from ZooKeeper for various reasons. For example, this problem occurs if the network is down, memory errors occurred, or embedded ZooKeeper restarted.
- Troubleshooting services and diagnostic tools
  Teracloud® Streams provides log and trace services and troubleshooting tools that can help you resolve the issues that you encounter when you work with the product.
- Teracloud® Streams messages
  The Teracloud® Streams messages describe the errors and solutions, warnings of potentially problematic conditions, and helpful information that you can use to troubleshoot the problems that can occur when you work with the product. These messages are displayed in the user interfaces and log files.
Reference
Find details on the SPL language, toolkits, APIs, commands, and more.
Glossary
Use this glossary to find terms and definitions for Teracloud® Streams.

Embedded ZooKeeper fails to start

In a shared file system environment, embedded ZooKeeper can fail to start if it is already running on another resource.

Embedded ZooKeeper fails to start on a resource, and an error message similar to the following example is displayed:

CDISA5309E ZooKeeper was not started on host1.ibm.com:40740 since it is running on a different host host2.ibm.com.

Check to see if the embedded ZooKeeper server process is running on the other resource.

To list the processes, enter the following command:

ps uxww | grep zookeeper

If the server process (com.ibm.streams.zookeeper.StreamsQuorumPeer) is running, stop embedded ZooKeeper on the other resource by entering streamtool embeddedzk --stop. Then start embedded ZooKeeper on the current resource by entering streamtool embeddedzk --start.
If embedded ZooKeeper is not running on the other resource and the problem still occurs, delete the zookeeper_server.host file. This file is located in the directory that is specified on the streams.zookeeper.property.dataDir bootstrap property. Then start embedded ZooKeeper on the current resource by entering streamtool embeddedzk --start.