feat(serverless): 502 errors

serverless/containers/how-to/add-trigger-to-a-container.mdx

@@ -55,6 +55,10 @@ The configuration of the queue retention can affect the behavior of the trigger.
 
 When a message is pushed to the selected queues, the container will be triggered with the message content passed in the event object's body.
 
+<Message type="note">
+  **Retry Policy:** If the Container returns a status code >=3XX, sending the message will be retried up to three times.
+</Message>
+
 ## NATS triggers
 
 [NATS triggers](/serverless/containers/concepts/#nats-trigger) allow you to automatically invoke a container using messages sent in a [NATS](/serverless/messaging/concepts/#nats) subject.
@@ -69,6 +73,10 @@ When a message is pushed to the selected queues, the container will be triggered
 6. Enter a **name** for your trigger and select the **NATS (Scaleway)** type, then select your NATS account and subject name.
 7. Click **Create trigger** to launch the trigger creation.
 
+<Message type="note">
+  **Retry Policy:** If the Container returns a status code >=3XX, sending the message will be retried up to three times.
+</Message>
+
 ## CRON triggers
 
 [CRON triggers](/serverless/containers/concepts/#cron-trigger) allow you to invoke your containers based on a recurring schedule. The CRON triggers for Serverless Containers use the **UTC** time zone.

serverless/containers/troubleshooting/502-error-when-scaling.mdx

@@ -0,0 +1,49 @@
+---
+meta:
+  title: Error code 502
+  description: Troubleshoot 502 issues while sending requests to Serverless Containers.
+content:
+  h1: Error code 502
+  paragraph: Troubleshoot 502 issues while sending requests to Serverless Containers.
+tags: serverless Containers troubleshooting issue error 502
+dates:
+  validation: 2025-01-03
+  posted: 2025-01-03
+categories:
+  - serverless
+---
+
+## Problem
+
+502 errors can sometimes occur on Serverless Containers during the autoscaling process when new container instances are being created.
+
+### Cause
+
+When a new instance is created, the Serverless health check verification is performed by default on the HTTP port. Once the port is opened, the resource is considered ready, and traffic starts being forwarded to it.
+
+This issue typically occurs when traffic is sent too early to the newly created container before it is fully deployed.
+
+### Possible solutions
+
+To ensure the Serverless Container is completely ready, both in terms of the HTTP port and the software scope, it is recommended to use **custom health checks**.
+
+**Custom health checks** can be configured via the API; in this case, it's recommended to implement a custom HTTP route on the Container that returns its readiness status.
+
+* [API Documentation for custom health checks](https://www.scaleway.com/en/developers/api/serverless-containers/#path-containers-update-an-existing-container) - Refer to the `health_check` parameter.
+
+<Message type="tip">
+  A simple health check to implement is just a simple `GET` on `/` to make sure the HTTP server is properly listening.
+
+  Example (incomplete) settings:
+  ```
+  health_check: {
+    http: {
+        path: "/"
+    }
+    }
+  ```
+</Message>
+
+<Message type="note">
+    The custom health check feature will be available in the Scaleway console in Q1 2025.
+</Message>

serverless/functions/how-to/add-trigger-to-a-function.mdx

@@ -53,6 +53,10 @@ The configuration of the queue retention may affect the behavior of the trigger.
 6. Enter a **name** for your trigger and select the **Queues (Scaleway)** type, then select your queue name.
 7. Click **Create trigger** to launch trigger creation.
 
+<Message type="note">
+  **Retry Policy:** If the Function returns a status code >=3XX, sending the message will be retried up to three times.
+</Message>
+
 ## NATS triggers
 
 [NATS triggers](/serverless/functions/concepts/#nats-trigger) allow you to automatically invoke a function using messages sent in a [NATS](/serverless/messaging/concepts/#nats) subject.
@@ -67,6 +71,10 @@ Scaleway [NATS subjects](/serverless/messaging/quickstart/#quickstart-for-nats)
 6. Enter a **name** for your trigger and select the **NATS (Scaleway)** type, then select your NATS account and subject name.
 7. Click **Create trigger** to launch trigger creation.
 
+<Message type="note">
+  **Retry Policy:** If the Function returns a status code >=3XX, sending the message will be retried up to three times.
+</Message>
+
 ## CRON triggers
 
 [CRON triggers](/serverless/functions/concepts/#cron-trigger) allow you to invoke your functions based on a recurring schedule. The CRON triggers for Serverless Functions use the **UTC** time zone.