Horovod Horovod fails with 'software caused connection abort'

What is Horovod Horovod fails with 'software caused connection abort'

Understanding Horovod

Horovod is an open-source distributed deep learning framework created by Uber. It is designed to make distributed deep learning fast and easy to use. Horovod achieves this by leveraging MPI (Message Passing Interface) to perform allreduce operations, which are crucial for synchronizing gradients across multiple nodes in a distributed training setup.

Identifying the Symptom

When using Horovod, you might encounter an error message that reads: 'software caused connection abort'. This error typically manifests during the execution of distributed training jobs and can cause the job to fail unexpectedly.

Exploring the Issue

What Does the Error Mean?

The error message 'software caused connection abort' indicates that a network connection was unexpectedly terminated by the software. This can happen due to various reasons, such as network instability, incorrect network configurations, or firewall settings that interfere with the communication between nodes.

Common Scenarios

This issue often arises in environments where network configurations are complex or when there are transient network failures. It is crucial to ensure that all nodes in the distributed setup can communicate with each other without interruptions.

Steps to Resolve the Issue

1. Verify Network Stability

Ensure that the network connections between all nodes are stable. You can use tools like PingPlotter or ping command to check the latency and packet loss between nodes:

ping -c 4

Look for any significant packet loss or high latency that could indicate network issues.

2. Check Firewall and Security Settings

Ensure that the firewall settings on each node allow traffic on the ports used by Horovod. Typically, Horovod uses MPI ports, which may vary depending on the configuration. You can check the firewall settings using:

sudo ufw status

Make sure the necessary ports are open. You can open a port using:

sudo ufw allow

3. Review Network Configuration

Check the network configuration files to ensure that there are no misconfigurations. This includes verifying the /etc/hosts file to ensure that all nodes are correctly listed with their respective IP addresses.

4. Increase Timeout Settings

Sometimes, increasing the timeout settings for network operations can help mitigate transient network issues. You can adjust these settings in your Horovod configuration or MPI settings, depending on your setup.

Conclusion

By following these steps, you should be able to resolve the 'software caused connection abort' error in Horovod. Ensuring stable network connections and correct configurations is key to successful distributed training. For more detailed information, you can refer to the Horovod documentation.