Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Update introduction.md #63

Open
wants to merge 1 commit into
base: master
Choose a base branch
from
Open

Update introduction.md #63

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions monitoring/introduction.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -56,3 +56,7 @@ counter.mqtt_connack_sent = 0

All available labels can be show using `vmq-admin metrics show --help`.

{% hint style="warning" %}
VerneMQ is a implemented in Erlang, which is a highly concurrent system, and follows a fail fast machanism. It might happen that in some scenarios the metrics do not seem to "match". One typcial example is sockets_open and sockets_close. In case of failure, the sockets_close metric might not be increased and thus there is a difference between opened sockets and closed sockets. The metric is nonetheless useful when inspecting the the running system.
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This seems to suggest that the metrics are somehow allowed to be wrong. For a Verne lifecycle (boot to boot) we expect metrics to be correct, though. Even socket close and open. If not, we missed a code flow to trigger counters.
After a reboot, those metrics are reset. So, I guess it depends what we mean by "In case of failure" in the snippet.
Just don't want to confuse readers, that's the main thing.

{% endhint %}