Terraform Error: Too many open files

What is Terraform Error: Too many open files

Understanding Terraform and Its Purpose

Terraform is an open-source infrastructure as code software tool created by HashiCorp. It allows users to define and provision data center infrastructure using a high-level configuration language known as HashiCorp Configuration Language (HCL), or optionally JSON. Terraform is used to manage both low-level components such as compute instances, storage, and networking, as well as high-level components such as DNS entries and SaaS features.

Identifying the Symptom: 'Error: Too many open files'

While using Terraform, you might encounter the error message: Error: Too many open files. This error typically occurs during the execution of Terraform commands, especially when dealing with a large number of resources or when running Terraform in environments with strict file descriptor limits.

What You Observe

When this error occurs, Terraform may fail to complete its operations, and you might see the error message in your terminal or logs. This can halt your infrastructure provisioning or management tasks, leading to incomplete deployments.

Explaining the Issue: File Descriptor Limits

The error 'Too many open files' is related to the file descriptor limit set by the operating system. Each process in a Unix-like operating system is allowed a certain number of file descriptors, which are used to manage open files, network connections, and other resources. When Terraform exceeds this limit, it cannot open additional files or connections, resulting in the error.

Why It Happens

This issue often arises in environments with a large number of resources or when Terraform is executed with parallelism, leading to a high number of simultaneous file operations. The default file descriptor limit might be insufficient for such operations.

Steps to Fix the 'Too Many Open Files' Error

To resolve this issue, you can increase the file descriptor limit on your system or adjust Terraform's execution to reduce the number of concurrent operations.

Increasing File Descriptor Limits

Follow these steps to increase the file descriptor limit:

Check the current limit using the command: ulimit -n To temporarily increase the limit for the current session, use: ulimit -n 4096 (replace 4096 with the desired limit) For a permanent solution, edit the /etc/security/limits.conf file and add the following lines: * soft nofile 4096 * hard nofile 4096 After editing, log out and log back in for the changes to take effect.

Adjusting Terraform Execution

If increasing the file descriptor limit is not feasible, consider reducing Terraform's parallelism:

Use the -parallelism flag with Terraform commands to limit the number of concurrent operations. For example: terraform apply -parallelism=10

Additional Resources

For more information on managing file descriptors and Terraform configurations, consider the following resources:

Terraform Apply Command Documentation Linux: Increase The Maximum Number Of Open Files

By following these steps, you should be able to resolve the 'Too many open files' error and ensure smooth execution of your Terraform operations.