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How To troubleshoot Netplan error when loading a config file in Ubuntu Server 18.04

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In this article, we will delve into the process of troubleshooting a Netplan error when loading a configuration file in Ubuntu Server 18.04. Netplan is a utility for easily configuring networking on a Linux system. However, like with any system, errors can occur. Let’s take a look at some common methods for diagnosing and resolving these issues.

Quick Answer

To troubleshoot a Netplan error when loading a config file in Ubuntu Server 18.04, start by using the --debug switch with the Netplan command to gather more information about the error. Then, use the --debug generate command to check for syntax errors in the configuration. If the issue persists, inspect the file using the od -bc command to look for hidden characters.

Understanding Netplan

Netplan is a command-line utility that was introduced in Ubuntu 17.10 to manage and configure network settings easily in Ubuntu systems. It allows you to configure network interfaces, create virtual networks, and manage routing tables, among other tasks.

Identifying the Problem

When you encounter an error while loading a Netplan configuration file, the first step is to understand the error message. Unfortunately, Netplan error messages can sometimes be vague, offering little insight into the specific issue.

Using the Debug Switch

One of the first steps in troubleshooting is to use the --debug switch with the Netplan command. This can be done by running the command sudo netplan --debug try. This command will attempt to apply your configuration, outputting additional debug information. This can often provide more detailed information about the error.

Generating the Configuration

Another useful command for troubleshooting is sudo netplan --debug generate. This command will attempt to generate the configuration files based on your Netplan configuration. If there are any syntax errors or formatting issues, they will likely be displayed in the output of this command.

Checking for Formatting Issues

Netplan uses YAML for its configuration syntax. YAML is a human-readable data serialization language. It’s important to note that YAML is very sensitive to correct formatting. You must use spaces for indentation, not tabs. Also, ensure there are no extra spaces or trailing characters.

A useful tool for checking the syntax of your YAML file is yamllint. This command-line utility will check your YAML file for syntax errors, duplicate keys, trailing spaces, tab characters, and other common mistakes.

Inspecting the File

If you’re still having trouble, you can inspect your Netplan configuration file using the od -bc command. This command will display the file in octal and ASCII format, allowing you to check for any hidden characters, such as tabs or special characters, that may be causing the error.

Conclusion

In conclusion, troubleshooting Netplan errors in Ubuntu Server 18.04 involves a process of elimination. Start by using the debug switch to gather more information about the error. Then, generate the configuration to check for syntax errors. Finally, inspect the file for hidden characters. By following these steps, you should be able to identify and resolve the issue.

Remember, the key to successful troubleshooting is patience and a systematic approach. Don’t be discouraged if the solution isn’t immediately apparent. With a bit of persistence, you can resolve your Netplan configuration issues and get your network up and running smoothly.

How do I install Netplan in Ubuntu Server 18.04?

Netplan is included by default in Ubuntu Server 18.04, so there is no need to install it separately. It should already be available for use.

How do I edit a Netplan configuration file?

To edit a Netplan configuration file, you can use a text editor such as nano or vi. For example, you can run sudo nano /etc/netplan/01-netcfg.yaml to edit the default configuration file. Make the necessary changes, save the file, and then apply the configuration using the sudo netplan apply command.

What should I do if I encounter a “Netplan apply error”?

If you encounter a "Netplan apply error," it usually means there is a syntax error or formatting issue in your Netplan configuration file. Double-check your file for any mistakes, such as incorrect indentation or missing colons. You can also use the sudo netplan --debug try command to get more detailed information about the error.

How can I check the status of my Netplan configuration?

To check the status of your Netplan configuration, you can use the sudo netplan --debug apply command. This command will attempt to apply the configuration and display any errors or warnings. If the configuration is successfully applied, you should see a message indicating that the configuration was applied without any errors.

Can I have multiple Netplan configuration files?

Yes, you can have multiple Netplan configuration files in the /etc/netplan/ directory. However, it’s important to note that the files are processed in alphabetical order, so make sure to name them accordingly to ensure the desired configuration is applied. You can also use the sudo netplan --debug generate command to check the generated configuration files based on your Netplan configuration.

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