iot route to kafka-built-by-myself vpc failed，but is passed before few days

Question

```
"failures": [
        {
            "failedAction": "KafkaAction",
            "failedResource": "fromIot",
            "errorMessage": "KafkaAction failed to send a message to the specified bootstrap servers. Topic fromIot not present in metadata after 1000 ms.. Message arrived on: $aws/events/presence/disconnected/17ce7c11b83b4, Action: kafka, topic: fromIot, bootstrap.servers: kafka.host:9092"
        }
    ]
```
i use kafka client on centos to check topic, topic is exist,  and  send messeage succeed.  bitnami/kafka:3.5.1

AndyAWS · Answer

From the error message, it seems the IoT service can't send a message to Kafka because it believes the topic "fromIot" is not present after waiting for 1000 ms.

### Possible Causes:
1. **Connection/Network Issues**
2. **Topic Discovery Latency**
3. **Kafka Configuration Issues**

### Diagnostic and Resolution Steps:

#### 1. **Test Connectivity**:
   - Ensure the IoT service can reach your Kafka cluster:
     ```bash
     telnet kafka.host 9092
     ```
   - If you can't connect, there might be network issues or firewall rules blocking the connection.

#### 2. **Increase Metadata Timeout**:
   - If topic discovery latency is the issue, consider increasing the metadata timeout on the IoT service's Kafka client.

#### 3. **Check Kafka Logs**:
   - Examine Kafka server logs for any warnings or errors related to the topic "fromIot" or client connections.

#### 4. **Kafka Configuration**:
   - Verify there are no changes in Kafka configurations that might affect topic creation, metadata, or client connections.

#### 5. **IoT Service Configuration**:
   - Review the IoT service's Kafka client configuration for any changes, especially concerning bootstrap servers, metadata, and timeouts.

#### 6. **Topic Replication**:
   - If your topic has multiple replicas, verify all replicas are in sync to avoid metadata discovery issues.

#### 7. **Restart Services**:
   - Consider restarting the IoT service or Kafka brokers to address potential transient issues.

#### 8. **Kafka Client Version**:
   - Ensure the Kafka client version used by the IoT service is compatible with your Kafka broker version (`bitnami/kafka:3.5.1`).

#### 9. **Topic Permissions**:
   - Ensure the IoT service has the required permissions to produce messages to the "fromIot" topic.

#### 10. **Use a Different Client**:
   - Test with a different Kafka client to see if the problem persists. This can help determine if the issue is with the IoT service's client or the Kafka setup.

iot route to kafka-built-by-myself vpc failed，but is passed before few days

Possible Causes:

Diagnostic and Resolution Steps:

1. Test Connectivity:

2. Increase Metadata Timeout:

3. Check Kafka Logs:

4. Kafka Configuration:

5. IoT Service Configuration:

6. Topic Replication:

7. Restart Services:

8. Kafka Client Version:

9. Topic Permissions:

10. Use a Different Client:

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