docs: Observability of Envoy Gateway Component (not Envoy)

[nezdolik]

Observability of Envoy Gateway Component (not Envoy):

To have full EG system observability and ease troubleshooting of various failure modes, is there is EG native metrics (not Envoy proxy) that helps to have insights into EG subcomponents like:

• Total/failed to translate resources (Resource translator)
• Total/failed to translate xDS resources (xDS translator)
• Total/failed to translate Infra resources (Infra translator)

Introducing such metrics (if they are not yet supported) will ease EG operators to troubleshoot various failure scenarios and increase confidence for prod deployment.

Could not find mentions of EG native metric in user docs.

[shawnh2]

Hi @nezdolik

The metrics of EG are still work in progress, tracked by #2092, for now, the latest version has support these metrics:

• https://github.com/envoyproxy/gateway/blob/main/internal/message/metrics.go
• https://github.com/envoyproxy/gateway/blob/main/internal/provider/kubernetes/metrics.go

The usage of EG metrics can refer to: https://gateway.envoyproxy.io/latest/tasks/observability/gateway-observability/

Total/failed to translate resources (Resource translator)
Total/failed to translate xDS resources (xDS translator)
Total/failed to translate Infra resources (Infra translator)

These metrics can refer to:

gateway/internal/message/metrics.go

Lines 15 to 17 in c5ec046

	watchableSubscribedTotal = metrics.NewCounter("watchable_subscribed_total", "Total number of subscribed watchable.")
	watchableSubscribedErrorsTotal = metrics.NewCounter("watchable_subscribed_errors_total", "Total number of subscribed watchable errors.")

with different runner label, for example, like:

• the gateway-api runner is for Resource translator
• the xds-translator runner is for xDS translator
• the infrastructure runner is for Infra translator

[arkodg]

converting this into a docs issue, because these metrics exist, but are not documented

[arkodg]

@Xunzhuo @zirain @shawnh2 is there a tool / tags to easily convert metrics to docs (.md) which we can publish in the docs website ?

[shawnh2]

Done some research, couldn't find any tool like that.

Since the metrics is not changed very often, maybe we could write a doc on our own.

[arkodg]

sure @shawnh2, lets start with that

[shawnh2]

will file a doc after #3393 landed