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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-03-09 13:19:48 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-03-09 13:20:02 +0000 |
commit | 58daab21cd043e1dc37024a7f99b396788372918 (patch) | |
tree | 96771e43bb69f7c1c2b0b4f7374cb74d7866d0cb /health/guides/vernemq/vernemq_mqtt_pubrel_sent_reason_unsuccessful.md | |
parent | Releasing debian version 1.43.2-1. (diff) | |
download | netdata-58daab21cd043e1dc37024a7f99b396788372918.tar.xz netdata-58daab21cd043e1dc37024a7f99b396788372918.zip |
Merging upstream version 1.44.3.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'health/guides/vernemq/vernemq_mqtt_pubrel_sent_reason_unsuccessful.md')
-rw-r--r-- | health/guides/vernemq/vernemq_mqtt_pubrel_sent_reason_unsuccessful.md | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/health/guides/vernemq/vernemq_mqtt_pubrel_sent_reason_unsuccessful.md b/health/guides/vernemq/vernemq_mqtt_pubrel_sent_reason_unsuccessful.md new file mode 100644 index 000000000..18e85e12a --- /dev/null +++ b/health/guides/vernemq/vernemq_mqtt_pubrel_sent_reason_unsuccessful.md @@ -0,0 +1,49 @@ +### Understand the alert + +This alert is related to VerneMQ, a high-performance MQTT broker. It monitors the number of unsuccessful v5 `PUBREL` packets sent in the last minute. If you receive this alert, it means that there was an issue with sending `PUBREL` packets in your VerneMQ instance. + +### What does PUBREL mean? + +`PUBREL` is a type of MQTT control packet that indicates the release of an application message from the server to the client. It is the third message in the QoS 2 (Quality of Service level 2) protocol exchange, where QoS 2 ensures that a message is delivered exactly once. An unsuccessful v5 `PUBREL` packet means that there was an error during the packet processing, and the message wasn't delivered to the client as expected. + +### Troubleshoot the alert + +1. Check the VerneMQ logs: + + VerneMQ logs can give you valuable information about possible errors that might have occurred during the processing of `PUBREL` packets. Look for any error messages or traces related to the `PUBREL` packets in the logs. + + ``` + sudo journalctl -u vernemq -f + ``` + + Alternatively, if you're using a custom log location: + + ``` + tail -f /path/to/custom/log + ``` + +2. Check the MQTT client-side logs: + + Check the logs of the MQTT client that might have caused the unsuccessful `PUBREL` packets. Look for any connection issues, error messages, or traces related to the MQTT protocol exchanges. + +3. Ensure proper configuration for VerneMQ: + + Verify that the VerneMQ configuration settings related to QoS 2 protocol timeouts and retries are correctly set. Check the VerneMQ [documentation](https://docs.vernemq.com/configuration) for guidance on the proper configuration. + + ``` + cat /etc/vernemq/vernemq.conf + ``` + +4. Monitor VerneMQ metrics: + + Use Netdata to monitor VerneMQ metrics to analyze the MQTT server's performance and resource usage. This can help you identify possible issues with the server. + +5. Address network or service issues: + + If the above steps don't resolve the alert, look for possible network or service-related issues that might be causing the unsuccessful `PUBREL` packets. This could require additional investigation based on your specific infrastructure and environment. + +### Useful resources + +1. [VerneMQ - Official Documentation](https://docs.vernemq.com/) +2. [MQTT Essentials: Quality of Service 2 (QoS 2)](https://www.hivemq.com/blog/mqtt-essentials-part-6-mqtt-quality-of-service-levels/) +3. [Netdata - VerneMQ monitoring](https://learn.netdata.cloud/docs/agent/collectors/go.d.plugin/modules/vernemq)
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