Scaleway Edge Services: Fixing The Backend Stage Zone Issue

Aug 4, 2025 by ADMIN 60 views

Scaleway Edge Services Backend Stage Zone Configuration Issue

Hey guys! Today we're diving deep into a tricky issue we've encountered with Scaleway Edge Services, specifically with how it handles zone configurations in the backend stage. This article will break down the problem, show you how to reproduce it, and even peek at the potential fix. So, buckle up and let's get started!

The Problem: Zone Ignorance in Edge Services Backend Stage

In a nutshell, the Scaleway Edge Services backend stage is ignoring the zone specified in the lb_config block when dealing with load balancer backends. Instead of using the zone where your load balancer actually lives, it defaults to the provider's default zone. This leads to a frustrating “lb not found” error, especially when your load balancer is chilling in a different zone. Understanding this zone configuration issue is crucial for anyone leveraging Scaleway's edge services with load balancers. This can be a real headache, especially when you're trying to manage resources across different zones for redundancy or compliance reasons. The incorrect zone configuration can lead to service disruptions and unexpected behavior. Therefore, it's essential to address this problem promptly to ensure the smooth operation of your edge services. Furthermore, the implications of this issue extend beyond just a simple error message; it can potentially impact the scalability and reliability of your applications if not handled correctly. The zone setting discrepancy between the Terraform configuration and the actual behavior of the Scaleway Edge Services can be a source of confusion and frustration for developers. In this article, we'll walk you through the technical details of the issue, providing you with a comprehensive understanding of how it manifests and what steps can be taken to mitigate it. We'll also delve into the root cause analysis and suggest a potential fix to help resolve this problem effectively. By addressing this zone configuration issue, we can ensure that Scaleway Edge Services functions as expected, allowing you to deploy and manage your applications with confidence.

Reproducing the Issue: A Step-by-Step Guide

Let’s get our hands dirty and reproduce this issue. Here’s what you'll need to do:

Set the Stage: First, create a load balancer in the fr-par-2 zone. This will be our guinea pig.
Provider Configuration: Next, configure your Terraform provider to use fr-par-1 as the default zone. This is where the conflict will arise.
The Terraform Code: Now, craft a scaleway_edge_services_backend_stage resource that references the load balancer we created. Pay close attention to the lb_config block.

resource "scaleway_edge_services_backend_stage" "example" {
  pipeline_id = scaleway_edge_services_pipeline.example.id
  lb_backend_config {
    lb_config {
      id          = "1b7ed179-ce0a-41d6-960d-86c4b4bd81b4"  # LB in fr-par-2
      frontend_id = "b4132a6c-4e44-4fde-99cc-9df9c68f29df"
      zone        = "fr-par-2"  # This is ignored!
      domain_name = "example.cluster.example.com"
      is_ssl      = true
    }
  }
}

Notice how we explicitly set the `zone` to `fr-par-2` in the `lb_config`, even though our provider default is `fr-par-1`. This is the key to triggering the issue. To **reproduce the zone configuration problem**, follow these steps precisely. Creating a load balancer in a specific zone is the first step in simulating the scenario where the zone mismatch occurs. Configuring the Terraform provider with a default zone that differs from the load balancer's zone is crucial for highlighting the issue. The **Terraform configuration** itself is designed to explicitly set the zone for the load balancer backend stage. By specifying the zone within the `lb_config` block, we expect the Edge Services backend stage to respect this setting and use it when looking up the load balancer. However, as we'll see, the resource ignores this specified zone and instead relies on the provider's default zone. This discrepancy between the intended behavior and the actual behavior is what leads to the error and highlights the **zone configuration issue**. Ensuring that your setup matches this configuration will allow you to consistently reproduce the problem and verify any potential fixes. The **step-by-step reproduction guide** helps in isolating the problem and provides a clear path for others to confirm the issue in their own environments.

Run the Magic: Fire up terraform apply and watch the fireworks (or rather, the error).

The Error: "lb not found"

If you followed the steps correctly, you should be greeted with a “lb not found” error. This is because Terraform is trying to find the load balancer in the provider's default zone (fr-par-1), but it actually resides in fr-par-2. This "lb not found" error is a direct consequence of the zone misconfiguration. The error message itself is a clear indication that the Edge Services backend stage is unable to locate the load balancer in the expected zone. This typically happens because the backend stage is looking in the wrong zone due to the zone configuration issue. The error can be particularly confusing because the configuration explicitly specifies the correct zone for the load balancer. This discrepancy between the specified zone and the actual zone being used by the Edge Services backend stage is the root cause of the problem. By understanding the context of this error and how it relates to the zone setting discrepancy, we can better diagnose and resolve the issue. The "lb not found" error not only prevents the successful creation of the backend stage but also highlights a fundamental flaw in how the resource handles zone configurations. Addressing this error is crucial for ensuring the reliability and predictability of Scaleway Edge Services deployments. This error serves as a clear indicator of the underlying zone configuration problem and emphasizes the need for a proper fix in the Terraform provider.

Debugging: Peeking Under the Hood

To really understand what's going on, let's dive into the debug output. Setting the TF_LOG=DEBUG environment variable will give us a peek at the API requests being made. This debugging process is essential for understanding the root cause of the issue. By examining the debug output, we can see exactly how the Terraform provider is interacting with the Scaleway API and identify any discrepancies in the zone being used. This level of detail is crucial for pinpointing the source of the zone configuration problem. The debug output analysis allows us to see the raw API requests and responses, which can reveal the exact zone being used in each request. This helps us confirm whether the zone specified in the configuration is being correctly passed to the API or if it's being overridden by the provider's default zone. This detailed examination is often necessary to fully understand the technical intricacies of the issue and to develop an effective solution. The process of debugging also involves comparing the expected behavior with the actual behavior to identify any deviations. This can involve looking at the Terraform configuration, the debug output, and the Scaleway API documentation to understand how the resource is intended to work and where the issue lies. By diving deep into the debug output, we can gain a comprehensive understanding of the zone configuration problem and identify the specific code that needs to be modified.

In our case, the API request shows the wrong zone:

{
  "scaleway_lb": {
    "lbs": [{
      "id": "1b7ed179-ce0a-41d6-960d-86c4b4bd81b4",
      "zone": "fr-par-1",  // Should be fr-par-2
      "frontend_id": "b4132a6c-4e44-4fde-99cc-9df9c68f29df",
      "is_ssl": true,
      "domain_name": "pierre-rigal.cluster.platane.io"
    }]
  }
}

See that "zone": "fr-par-1"? That's the culprit! It should be fr-par-2. The incorrect zone in the API request is the smoking gun in this case. It clearly demonstrates that the Terraform provider is using the provider's default zone instead of the zone specified in the configuration. This discrepancy is the direct cause of the "lb not found" error and confirms the zone configuration issue. The debug output highlights the critical importance of verifying API requests when troubleshooting Terraform issues. By examining the raw requests, we can see exactly what data is being sent to the Scaleway API and identify any errors or inconsistencies. This level of detail is essential for diagnosing complex problems like the zone configuration issue. The debug output analysis provides valuable insights into the inner workings of the Terraform provider and helps us understand how the resource is handling zone settings. By identifying the incorrect zone in the API request, we can focus our attention on the specific code that's responsible for this behavior and develop a targeted solution.

The response confirms our suspicions: HTTP/2.0 404 Not Found with error {"message":"lb not found"}. This 404 Not Found error further solidifies the fact that the load balancer is not being found in the specified zone. The combination of the incorrect zone in the API request and the 404 error response paints a clear picture of the zone configuration problem. The error message {"message":"lb not found"} is a direct consequence of the zone mismatch. The Scaleway API is unable to locate the load balancer in the zone specified in the request, leading to the 404 error. This error response provides further confirmation that the zone configuration issue is preventing the Terraform provider from correctly identifying the load balancer. The 404 Not Found error is a critical piece of information that helps us understand the scope and impact of the problem. It highlights the importance of addressing the zone configuration issue to ensure the successful deployment of Scaleway Edge Services.

Root Cause Analysis: Diving into the Code

Let's put on our detective hats and dig into the provider's source code. The issue lies in internal/services/edgeservices/types.go, specifically in the expandLBBackendConfig function. This root cause analysis is the key to fixing the problem. By examining the code, we can identify the exact location where the zone is being incorrectly set and understand why this is happening. This level of understanding is essential for developing a robust and effective solution to the zone configuration issue. The process of root cause analysis involves tracing the flow of data and control through the code to identify the source of the problem. This can involve examining the function's inputs, outputs, and internal logic to understand how it's handling zone settings. The analysis of the expandLBBackendConfig function is crucial because this function is responsible for expanding the load balancer backend configuration and creating the data structure that will be used in the API request. If the zone is being incorrectly set in this function, it will propagate through the rest of the code and lead to the zone mismatch. The goal of root cause analysis is not just to identify the symptom (the "lb not found" error) but also to understand the underlying cause of the problem so that it can be addressed effectively. This ensures that the issue is resolved permanently and doesn't resurface in the future.

Here’s the problematic snippet:

lbConfig := &edge_services.ScalewayLB{
    ID:         locality.ExpandID(innerMap["id"]),
    Zone:       zone,  // This overrides the zone from config!
    FrontendID: locality.ExpandID(innerMap["frontend_id"]),
    IsSsl:      types.ExpandBoolPtr(innerMap["is_ssl"]),
    DomainName: types.ExpandStringPtr(innerMap["domain_name"]),
}

See that Zone: zone? The function is receiving a zone parameter (from the provider/API client configuration) and using it, overriding the zone specified in the configuration. This code snippet is the smoking gun in our investigation. It clearly shows that the Zone field of the lbConfig struct is being set to the zone parameter passed to the function, regardless of the zone specified in the Terraform configuration. This is the direct cause of the zone configuration issue. The comment // This overrides the zone from config! highlights the intentional nature of this behavior, although it's clearly not the desired outcome. This analysis of the code reveals a fundamental flaw in how the expandLBBackendConfig function handles zone settings. It prioritizes the provider's default zone over the zone explicitly specified in the configuration, leading to the zone mismatch. The discovery of this problematic snippet is a critical step in resolving the issue. By understanding the exact location where the zone is being incorrectly set, we can develop a targeted fix that addresses the root cause of the problem.

Workaround: The CLI to the Rescue

While we wait for a proper fix, there's a workaround! Using the Scaleway CLI, you can create the backend stage with the correct zone:

scw edge-services backend-stage create \
  pipeline-id=2551314b-2199-4d33-801d-16e9ae6770ab \
  scaleway-lb.lbs.0.id=1b7ed179-ce0a-41d6-960d-86c4b4bd81b4 \
  scaleway-lb.lbs.0.zone=fr-par-2 \
  scaleway-lb.lbs.0.frontend-id=b4132a6c-4e44-4fde-99cc-9df9c68f29df \
  scaleway-lb.lbs.0.is-ssl=true \
  scaleway-lb.lbs.0.domain-name=example.cluster.example.com

This CLI workaround provides a temporary solution for creating Edge Services backend stages with the correct zone. By using the Scaleway CLI, you can explicitly specify the zone for the load balancer, bypassing the issue in the Terraform provider. This can be particularly useful in situations where you need to create backend stages quickly and cannot wait for a fix to be implemented in the provider. The CLI workaround demonstrates that the underlying Scaleway API correctly handles zone settings when explicitly provided. This further reinforces the conclusion that the issue lies within the Terraform provider and not the API itself. While the CLI workaround is a viable option, it's important to remember that it's a temporary solution. Ideally, the zone configuration issue should be addressed in the Terraform provider to ensure a consistent and predictable experience for all users. The availability of this workaround allows users to continue working with Scaleway Edge Services while the underlying issue is being resolved.

Suggested Fix: Respect the Config!

Here’s a potential fix for the expandLBBackendConfig function:

// Use the zone from config if specified, otherwise fall back to the provider zone
configZone := innerMap["zone"].(string)
if configZone != "" {
    lbConfig.Zone = scw.Zone(configZone)
} else {
    lbConfig.Zone = zone
}

The idea is simple: if a zone is specified in the configuration, use it. Otherwise, fall back to the provider's default zone. This suggested fix addresses the root cause of the zone configuration issue by ensuring that the zone specified in the Terraform configuration is respected. The code snippet introduces a conditional check that prioritizes the zone from the configuration over the provider's default zone. This aligns with the expected behavior and resolves the zone mismatch problem. The proposed fix is relatively straightforward and easy to implement. It involves adding a simple if-else statement to the expandLBBackendConfig function to handle zone settings correctly. This approach minimizes the risk of introducing new issues and ensures that the fix is targeted and effective. The suggested solution not only resolves the zone configuration issue but also improves the overall usability of the Terraform provider by making it more intuitive and predictable. By respecting the zone specified in the configuration, the provider aligns with user expectations and simplifies the process of managing Scaleway Edge Services.

Conclusion

So, there you have it! We've dissected the Scaleway Edge Services backend stage zone configuration issue, reproduced it, debugged it, and even suggested a fix. Hopefully, this deep dive helps you understand the problem and provides you with a workaround until a proper fix is released. Keep an eye on the Scaleway provider releases for updates! Understanding the intricacies of zone configuration is essential for effectively managing cloud resources. The Scaleway Edge Services backend stage zone configuration issue highlights the importance of paying close attention to zone settings and ensuring that they are correctly configured. By understanding the root cause of the issue and implementing the suggested fix, we can ensure that our deployments are reliable and predictable. The process of troubleshooting and debugging this issue has provided valuable insights into the inner workings of the Terraform provider and the Scaleway API. This knowledge can be applied to other issues and help us become more effective cloud engineers. The zone configuration issue serves as a reminder that even seemingly small configuration errors can have significant consequences. By taking the time to understand these issues and address them proactively, we can prevent service disruptions and ensure the smooth operation of our cloud applications. The resolution of this zone configuration issue will ultimately improve the user experience and make it easier to manage Scaleway Edge Services with Terraform.