Troubleshooting

Review the troubleshooting tips and the common issues that can occur with IBM Edge Computing for Devices to help you troubleshoot any issues that you encounter.

The following troubleshooting guides describe the main components of an IBM Edge Computing for Devices system and how to investigate the included interfaces to determine the state of the system.

Troubleshooting tools

Many interfaces that are included with IBM Edge Computing for Devices provide status information. Some of this information is available through graphical web interfaces, but most information is available through HTTP REST APIs. A Linux shell command line tool, hzn, is included on your edge nodes to serve primarily as a wrapper to simplify accessing these REST interfaces.

In addition, the IBM Event Streams, which is used by IBM Edge Computing for Devices, uses Kafka for messaging. You can connect to the Kafka streams for IBM Edge Computing for Devices to help you subscribe to messages to help you troubleshoot issues. You can use the kafkacat command to help you simplify subscribing to messages.

On an edge node you might need to troubleshoot host issues, the underlying Horizon software, Docker issues, and the code that is running in custom containers.

If you need to troubleshoot Docker issues, use the Docker tools and interfaces. For more information, see the Docker documentation.

IBM Edge Computing for Devices troubleshooting tools

The preceding image shows the IBM Edge Computing for Devices interfaces that provide information about the system state and the tools that you can use to access the interfaces.

On edge nodes where Horizon is installed, the hzn command is a useful tool for debugging issues with the local Horizon agent and the remote Horizon exchange in the cloud. The hzn command is a wrapper for the provided HTTP REST APIs. The hzn command is designed to simplify access to system state information. The hzn command includes built-in online help, which you can use to obtain information about commands to use and command details. To view this help information, you can run the hzn --help or hzn \<subcommand\> --help commands.

For more information about the Horizon REST API, see:

On nodes where the Horizon packages are either not supported or not installed, you can directly access the HTTP REST APIs instead, such as through curl or other CLI utilities, or by writing a program in a language that supports REST queries. IBM Event Streams provides graphical web pages that you can use to access information. Alternatively, you can directly interact with the IBM Event Streams Kafka servers manually or through your code.

Troubleshooting tips

To help you troubleshoot specific issues, review the questions about your system state, and any associated tips, on the following topics. For each question, a description of why the question is relevant to troubleshooting your system is provided. For some questions, tips or a detailed guide is provided for learning about how to obtain the related information for your system.

These questions are separated, as the nature of debugging issues that are related to each environment can be different. For instance, when troubleshooting issues on an edge node, you might have complete access to and control over the node, which can provide you more capability to collect and view information.