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Troubleshooting Cloud-Init User-Data File Not Picked Up During Ubuntu 20.04 PXE Deployment

Ubuntu 17

When deploying Ubuntu 20.04 using PXELINUX and cloud-init, you may encounter an issue where the user-data file is not being picked up during the installation process. This article will guide you through a series of steps to troubleshoot and resolve this issue.

Verifying the Accessibility of the User-Data File

The first step in troubleshooting is to ensure that the user-data file is located in the correct directory and has the correct permissions. The default location for the user-data file in Ubuntu 20.04 is /var/www/html/ubuntu/cloud-init.

To check the file location and permissions, use the following command:

ls -l /var/www/html/ubuntu/cloud-init/user-data

This command lists the files in the specified directory along with their permissions. The output should show that the user-data file is present and has read permissions for the web server.

Checking the APPEND Line URL

The PXELINUX configuration file contains an APPEND line that specifies the URL for the user-data file. This URL needs to be correct and resolvable for the installer to pick up the user-data file.

The APPEND line might look something like this:

APPEND initrd=ubuntu/initrd.gz ks=http://<server>/ubuntu/cloud-init/user-data

Ensure that the URL specified in the APPEND line is correct and can be resolved properly. If you are using a short name for the server, try using the IP address instead.

Verifying the Cloud-Init Configuration

The user-data file is a cloud-init configuration file that contains instructions for the Ubuntu installer. If this file has errors or is not properly formatted, the installer may not pick it up.

You can validate the syntax of your user-data file using a YAML validator, such as YAMLLint. Make sure the autoinstall section is properly defined according to the Ubuntu autoinstall documentation.

Checking the Web Server Logs

The web server logs can provide valuable information about whether the installer is attempting to access the user-data file and any errors that may occur during this process.

To view the Apache access logs, use the following command:

tail /var/log/apache2/access.log

Look for entries that correspond to the user-data file. If you see 404 errors, this indicates that the file could not be found.

Using a Full URL for the User-Data File

Instead of using a relative path for the user-data file in the APPEND line, try using a full URL. This can help ensure that the installer can access the file correctly.

For example, change the APPEND line to:

APPEND initrd=ubuntu/initrd.gz ks=http://<server-ip>/ubuntu/cloud-init/user-data

Verifying Network Connectivity

Finally, ensure that the network configuration in your user-data file is correct and that the installer can access the network properly to download the user-data file.

You can use the ping command to check network connectivity:

ping <server-ip>

If the ping command returns an error, this indicates a network connectivity issue that needs to be resolved.

By following these steps, you should be able to diagnose and resolve issues with the user-data file not being picked up during Ubuntu 20.04 PXE deployment. If you continue to experience issues, consider seeking help from the Ubuntu community.

What is cloud-init?

Cloud-init is a package that runs on the first boot of a virtual machine instance in cloud environments. It allows you to customize and configure the instance during its initial provisioning.

How can I check the permissions of a file in Ubuntu?

You can use the ls -l command followed by the file path to check the permissions of a file in Ubuntu. For example, to check the permissions of the user-data file, you can run ls -l /var/www/html/ubuntu/cloud-init/user-data.

What is the default location for the user-data file in Ubuntu 20.04?

The default location for the user-data file in Ubuntu 20.04 is /var/www/html/ubuntu/cloud-init.

How can I validate the syntax of a YAML file?

You can use a YAML validator, such as YAMLLint, to validate the syntax of a YAML file. YAMLLint is a command-line tool that checks YAML files for syntax errors and provides suggestions for improvement.

How can I view the Apache access logs in Ubuntu?

You can view the Apache access logs in Ubuntu by using the tail command followed by the path to the access log file. For example, to view the access logs in Apache, you can run tail /var/log/apache2/access.log.

What does a `404` error in the Apache access logs indicate?

A 404 error in the Apache access logs indicates that the requested file could not be found. This could mean that the user-data file is not located in the specified directory or that the URL specified in the APPEND line is incorrect.

How can I check network connectivity in Ubuntu?

You can use the ping command followed by the IP address or hostname of the server to check network connectivity in Ubuntu. For example, to check connectivity to a server with the IP address 192.168.1.100, you can run ping 192.168.1.100.

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