docs: Grafana Dashboard Configuration

[Sindweller]

Please answer these questions before submitting a pull request

• Why submit this pull request?

• Bugfix

• New feature provided

• Improve performance

• Backport patches

• Related issues

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New feature or improvement

• Describe the details and related test reports.
  This pr has a prior pr feat: expose more prometheus metrics #670 .
  A shortcut of Grafana Dashboard for apisix-ingress-controller:

[tao12345666333]

ping @Sindweller any updates?

[codecov-commenter]

Codecov Report

Merging #731 (4affd60) into master (b127ff4) will increase coverage by 0.64%.
The diff coverage is 34.24%.

@@            Coverage Diff             @@
##           master     #731      +/-   ##
==========================================
+ Coverage   32.50%   33.14%   +0.64%     
==========================================
  Files          66       67       +1     
  Lines        6800     7142     +342     
==========================================
+ Hits         2210     2367     +157     
- Misses       4340     4505     +165     
- Partials      250      270      +20     

Impacted Files	Coverage Δ
pkg/api/router/router.go	72.72% <ø> (-2.28%)	⬇️
pkg/api/validation/apisix_consumer.go	0.00% <0.00%> (ø)
pkg/api/validation/apisix_route.go	21.73% <0.00%> (+2.50%)	⬆️
pkg/api/validation/apisix_tls.go	0.00% <0.00%> (ø)
pkg/api/validation/apisix_upstream.go	0.00% <0.00%> (ø)
pkg/apisix/apisix.go	67.50% <ø> (ø)
pkg/apisix/schema.go	62.26% <0.00%> (-2.45%)	⬇️
pkg/ingress/apisix_cluster_config.go	0.00% <0.00%> (ø)
pkg/ingress/apisix_consumer.go	0.00% <0.00%> (ø)
pkg/ingress/apisix_route.go	0.00% <0.00%> (ø)
... and 37 more

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[tao12345666333]

Can you add a document describing how to monitor and use this dashboard? Thanks

If you need any help please feel free to ping me.

[tokers]

@Sindweller What does the cluster health check value mean?

[Sindweller]

Can you add a document describing how to monitor and use this dashboard? Thanks

If you need any help please feel free to ping me.

working on it now.

[Sindweller]

@Sindweller What does the cluster health check value mean?

It increases when checkClusterHealth is called to record a successful health check for default cluster.

[tokers]

@Sindweller What does the cluster health check value mean?

It increases when checkClusterHealth is called to record a successful health check for default cluster.

OK, so what about APISIX Health Check Calls, so that we know the usage of this metrics.

[tao12345666333]

@Sindweller Thanks! It looks great to me!

Please fix the markdown lint error. Then we can merge this one.

[tao12345666333]

@Sindweller LGTM. Thanks!