Add klaytn binary version information into Prometheus metric

[odg0318]

Is your request related to a problem? Please describe.

To check the klaytn binary version, I must connect to the instance shell and execute the binary like below.

$  kcn version
Klaytn v1.8.3

I want to check the binary version through Prometheus metrics.

Describe the solution you'd like

I suggest a new metric showing version information by Prometheus label.

klaytn_node_version{version="1.8.3"} 1

Metric name is klaytn_node_version and value is constantly 1.

The version information can be referred in the following code.
https://github.com/klaytn/klaytn/blob/dev/params/version.go#L33

Describe alternatives you've considered

N/A

Additional context

N/A

[kjhman21]

@aidan-kwon Could you please take a look at this?

[aidan-kwon]

@odg0318 Thank you for the suggestion.
Actually, I am sure grafana can show labels of multiple nodes. If you know about this, please give us the link for the documents.

I think we can achieve the goal with another way.
How about setting VersionMajor * 10000 + VersionMinor * 100 + VersionPatch for the value of the version metric ?
Or we can make multiple metrics for each VersionMajor, VersionMinor, VersionPatch.

[odg0318]

@aidan-kwon Using label in prometheus for version is very common way. I think using label is better way. Let me share some examples from other project. node_exporter is very popular project for monitoring node status.

Three metrics are used for version with value 1.

• go_info
• node_exporter_build_info
• node_os_info

The labels in Prometheus can be shown in Grafana table type.

example: node_exporter

 HELP go_info Information about the Go environment.
# TYPE go_info gauge
go_info{version="go1.17.3"} 1

# HELP node_exporter_build_info A metric with a constant '1' value labeled by version, revision, branch, and goversion from which node_exporter was built.
# TYPE node_exporter_build_info gauge
node_exporter_build_info{branch="HEAD",goversion="go1.17.3",revision="a2321e7b940ddcff26873612bccdf7cd4c42b6b6",version="1.3.1"} 1

# HELP node_os_info A metric with a constant '1' value labeled by build_id, id, id_like, image_id, image_version, name, pretty_name, variant, variant_id, version, version_codename, version_id.# TYPE node_os_info gauge
node_os_info{build_id="",id="amzn",id_like="centos rhel fedora",image_id="",image_version="",name="Amazon Linux",pretty_name="Amazon Linux 2",variant="",variant_id="",version="2",version_codename="",version_id="2"} 1