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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.
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.
Stream applications
Use these solutions to resolve the problems that you might encounter when you develop stream applications.
Processing element problems when the maximum number of file descriptors or the maximum number of user processes is exceeded
When the number of processing elements (PEs) or the number of external connections for a PE exceeds the maximum number of open file descriptors or the maximum number of user processes, the PEs might fail to start or to connect correctly.

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.
    - Authentication
      Use the solutions that are provided to resolve problems with Teracloud® Streams authentication.
    - Connectivity
      Use the solutions that are provided to resolve connectivity problems with the product.
    - Domain configuration and administration
      Use the solutions that are provided to resolve the problems that can occur when you work with Teracloud® Streams domains.
    - Installation
      Use the solutions that are provided to resolve the problems that you can encounter when you install Teracloud® Streams.
    - Instance configuration and administration
      Use the solutions that are provided to resolve the problems that can occur when you work with Teracloud® Streams instances.
    - Streams Console
      Use the solutions that are provided to resolve the problems that you might encounter when you work with Streams Console.
    - Stream applications
      Use these solutions to resolve the problems that you might encounter when you develop stream applications.
      - Processing element problems when the maximum number of file descriptors or the maximum number of user processes is exceeded
        When the number of processing elements (PEs) or the number of external connections for a PE exceeds the maximum number of open file descriptors or the maximum number of user processes, the PEs might fail to start or to connect correctly.
      - Processing element startup problems
        If the processing elements fail to start after you submit an application job, you might have to increase the value of the hc.pecStartTimeout property for the domain controller service.
      - Getting rid of the Uncrustify source code formatter warning message
        To ensure that your C++ code is indented and formatted correctly when you generate code by using the sc command, you can optionally install and use the Uncrustify source code formatter. If you do not install this formatter, a warning message is displayed when you compile your code and use the code beautification option.
      - Conflicts requesting ports from the local port range
        An error is generated when the TCPSink, TCPSource, UDPSource, or UDPSink operator of an application specifies the port that Teracloud® Streams is already using, and the application is launched.
    - Teracloud® Streams runtime
      Use the solutions that are provided to resolve the problems encountered during the Teracloud® Streams runtime processes.
  - 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.
- 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.

Processing element problems when the maximum number of file descriptors or the maximum number of user processes is exceeded

When the number of processing elements (PEs) or the number of external connections for a PE exceeds the maximum number of open file descriptors or the maximum number of user processes, the PEs might fail to start or to connect correctly.

The PE starts and then terminates, the PE fails to start, the PE starts but fails to reach a healthy state, or the PE starts and reaches an unknown state. You might also see a message in the PE trace file that contains the following information:

errno=Too many open files
Exception trying to start a new thread

The possible causes include:

The number of external connections for a PE exceeds the maximum number of file descriptors that are configured for Linux™. A Linux™ system limits the number of file descriptors that a Linux™ process can use. A PE requires a file descriptor for each Teracloud® Streams connection that it opens, and therefore can reach the current limit when the application topology requires many connections.
The total number of PEs for the instance causes either the maximum number of open file descriptors or the maximum number of user processes to be exceeded.

To resolve these problems:

Verify that your ulimit settings satisfy Teracloud® Streams requirements and update your settings, if needed. For more information, see Guidelines for configuring Linux™ ulimit settings for Teracloud® Streams.
Reduce the number of connections that are required for each PE by configuring your application to use additional Split operators. For example, rather than connecting one PE to 1,200 PEs, add ten Split operators that each connect to 120 PEs.
For each process, increase the maximum number of configured file descriptors to be greater than the number of external connections for a PE. To tune the file descriptor parameters of the kernel, contact your Linux™ system administrator.
On the system that has the problem, reduce the number of PEs that run in an instance by specifying how operators in applications are fused into PEs..