Docs: fix user metrics doc

doc/README.md

@@ -176,7 +176,7 @@ instant how code changes impact your production environment.
 
 - [GitLab Prometheus](administration/monitoring/prometheus/index.md): Configure the bundled Prometheus to collect various metrics from your GitLab instance.
 - [Prometheus project integration](user/project/integrations/prometheus.md): Configure the Prometheus integration per project and monitor your CI/CD environments.
-- [Prometheus metrics](user/project/integrations/prometheus_library/metrics.md): Let Prometheus collect metrics from various services, like Kubernetes, NGINX, NGINX ingress controller, HAProxy, and Amazon Cloud Watch.
+- [Prometheus metrics](user/project/integrations/prometheus_library/index.md): Let Prometheus collect metrics from various services, like Kubernetes, NGINX, NGINX ingress controller, HAProxy, and Amazon Cloud Watch.
 - [GitLab Performance Monitoring](administration/monitoring/performance/index.md): Use InfluxDB and Grafana to monitor the performance of your GitLab instance (will be eventually replaced by Prometheus).
 - [Health check](user/admin_area/monitoring/health_check.md): GitLab provides liveness and readiness probes to indicate service health and reachability to required services.
 - [GitLab Cycle Analytics](user/project/cycle_analytics.md): Cycle Analytics measures the time it takes to go from an

doc/ci/environments.md

@@ -586,13 +586,13 @@ exist, you should see something like:
 >
 > - For the monitoring dashboard to appear, you need to:
 >   - Have enabled the [Prometheus integration][prom]
->   - Configured Prometheus to collect at least one [supported metric](../user/project/integrations/prometheus_library/metrics.md)
+>   - Configured Prometheus to collect at least one [supported metric](../user/project/integrations/prometheus_library/index.md)
 > - With GitLab 9.2, all deployments to an environment are shown directly on the
 >  monitoring dashboard
 
 If you have enabled [Prometheus for monitoring system and response metrics](https://docs.gitlab.com/ee/user/project/integrations/prometheus.html), you can monitor the performance behavior of your app running in each environment.
 
-Once configured, GitLab will attempt to retrieve [supported performance metrics](https://docs.gitlab.com/ee/user/project/integrations/prometheus_library/metrics.html) for any
+Once configured, GitLab will attempt to retrieve [supported performance metrics](https://docs.gitlab.com/ee/user/project/integrations/prometheus_library/index.html) for any
 environment which has had a successful deployment. If monitoring data was
 successfully retrieved, a Monitoring button will appear for each environment.
 

doc/user/project/integrations/prometheus.md

@@ -56,7 +56,7 @@ The [NGINX Ingress](../clusters/index.md#installing-applications) that is deploy
 Integration with Prometheus requires the following:
 
 1. GitLab 9.0 or higher
-1. Prometheus must be configured to collect one of the [supported metrics](prometheus_library/metrics.md)
+1. Prometheus must be configured to collect one of the [supported metrics](prometheus_library/index.md)
 1. Each metric must be have a label to indicate the environment
 1. GitLab must have network connectivity to the Prometheus server
 
@@ -65,7 +65,7 @@ Integration with Prometheus requires the following:
 Installing and configuring Prometheus to monitor applications is fairly straight forward.
 
 1. [Install Prometheus](https://prometheus.io/docs/introduction/install/)
-1. Set up one of the [supported monitoring targets](prometheus_library/metrics.md)
+1. Set up one of the [supported monitoring targets](prometheus_library/index.md)
 1. Configure the Prometheus server to [collect their metrics](https://prometheus.io/docs/operating/configuration/#scrape_config)
 
 #### Configuration in GitLab

doc/user/project/integrations/prometheus_library/cloudwatch.md

@@ -27,4 +27,4 @@ A sample Cloudwatch Exporter configuration file, configured for basic AWS ELB mo
 ## Specifying the Environment label
 
 In order to isolate and only display relevant metrics for a given environment
-however, GitLab needs a method to detect which labels are associated. To do this, GitLab will [look for an `environment` label](metrics.md#identifying-environments).
+however, GitLab needs a method to detect which labels are associated. To do this, GitLab will [look for an `environment` label](index.md#identifying-environments).

doc/user/project/integrations/prometheus_library/haproxy.md

@@ -21,4 +21,4 @@ To get started with NGINX monitoring, you should install and configure the [HAPr
 ## Specifying the Environment label
 
 In order to isolate and only display relevant metrics for a given environment
-however, GitLab needs a method to detect which labels are associated. To do this, GitLab will [look for an `environment` label](metrics.md#identifying-environments).
+however, GitLab needs a method to detect which labels are associated. To do this, GitLab will [look for an `environment` label](index.md#identifying-environments).

doc/user/project/integrations/prometheus_library/index.md

+# Prometheus Metrics library
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8935) in GitLab 9.0.
+
+GitLab offers automatic detection of select [Prometheus exporters](https://prometheus.io/docs/instrumenting/exporters/).
+
+## Exporters
+
+Currently supported exporters are:
+
+- [Kubernetes](kubernetes.md)
+- [NGINX](nginx.md)
+- [NGINX Ingress Controller](nginx_ingress.md)
+- [HAProxy](haproxy.md)
+- [Amazon Cloud Watch](cloudwatch.md)
+
+We have tried to surface the most important metrics for each exporter, and will
+be continuing to add support for additional exporters in future releases. If you
+would like to add support for other official exporters, contributions are welcome.
+
+## Identifying Environments
+
+GitLab retrieves performance data from the configured Prometheus server, and
+attempts to identifying the presence of known metrics. Once identified, GitLab
+then needs to be able to map the data to a particular environment.
+
+In order to isolate and only display relevant metrics for a given environment,
+GitLab needs a method to detect which labels are associated. To do that,
+GitLab uses the defined queries and fills in the environment specific variables.
+Typically this involves looking for the
+[`$CI_ENVIRONMENT_SLUG`](../../../../ci/variables/README.md#predefined-variables-environment-variables),
+but may also include other information such as the project's Kubernetes namespace.
+Each search query is defined in the [exporter specific documentation](#exporters).

doc/user/project/integrations/prometheus_library/metrics.md

-# Prometheus Metrics library
-
-> [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8935) in GitLab 9.0
-
-GitLab offers automatic detection of select [Prometheus exporters](https://prometheus.io/docs/instrumenting/exporters/). Currently supported exporters are:
-* [Kubernetes](kubernetes.md)
-* [NGINX](nginx.md)
-* [NGINX Ingress Controller](nginx_ingress.md)
-* [HAProxy](haproxy.md)
-* [Amazon Cloud Watch](cloudwatch.md)
-
-We have tried to surface the most important metrics for each exporter, and will be continuing to add support for additional exporters in future releases. If you would like to add support for other official exporters, [contributions](#adding-to-the-library) are welcome.
-
-## Identifying Environments
-
-GitLab retrieves performance data from the configured Prometheus server, and attempts to identifying the presence of known metrics. Once identified, GitLab then needs to be able to map the data to a particular environment.
-
-In order to isolate and only display relevant metrics for a given environment, GitLab needs a method to detect which labels are associated. To do that,
-GitLab uses the defined queries and fills in the environment specific variables. Typically this involves looking for the [$CI_ENVIRONMENT_SLUG](../../../../ci/variables/README.md#predefined-variables-environment-variables), but may also include other information such as the project's Kubernetes namespace. Each search query is defined in the [exporter specific documentation](#prometheus-metrics-library).
+This document was moved to [another location](index.md).

doc/user/project/integrations/prometheus_library/nginx.md

@@ -27,4 +27,4 @@ If you are using NGINX as your Kubernetes ingress, GitLab will [automatically de
 ## Specifying the Environment label
 
 In order to isolate and only display relevant metrics for a given environment
-however, GitLab needs a method to detect which labels are associated. To do this, GitLab will [look for an `environment` label](metrics.md#identifying-environments).
+however, GitLab needs a method to detect which labels are associated. To do this, GitLab will [look for an `environment` label](index.md#identifying-environments).