Merge pull request #58 from MalloZup/documentation-metric

 document metrics specification (initial effort and skeleton, pacemaker)

README.md

@@ -34,6 +34,10 @@ For a terraform deployment you can also read: https://github.com/SUSE/ha-sap-ter
 
 - show SBD disk health metrics
 
+- show DRBD metrics (local and remote disks resource metrics)
+
+We mantain a complete list of the [metric specification](doc/metric_spec.md), usage and possible values.
+
 ## Devel:
 
 Build the binary with `make` and run it inside a node of the ha cluster, it will show the metrics on port `9002` by default.

doc/metric_spec.md

@@ -0,0 +1,112 @@
+# Metrics specification:
+
+This is a specification of metrics exposed by the ha_cluster exporter.
+
+All metrics from the exporter start with the prefix `ha_cluster`
+
+Below you have a complete specification, ordered by component.
+
+1. [pacemaker](#pacemaker)
+2. [drbd](#drbd)
+3. [sbd](#sbd)
+4. [corosyncl](#corosync)
+
+# Pacemaker 
+
+The Pacemaker cluster metrics are atomic metrics and represent and updated snapshot of the HA cluster, retrieved fetching the XML CIB of pacemaker.
+
+Some of the pacemaker metrics like `ha_cluster_node_resources` and `ha_cluster_nodes` metrics with labels share a common trait:
+
+they can be either set to `1` or they are absent, this is because they track the real state of the cluster resources monitored.
+
+1. [ha_cluster_node_resources](#ha_cluster_node_resources)
+2. [ha_cluster_nodes](#ha_cluster_nodes)
+3. [ha_cluster_nodes_configured_total](#ha_cluster_nodes_configured_total)
+4. [ha_cluster_resources_configured_total](#ha_cluster_resources_configured_total)
+
+
+
+## ha_cluster_node_resources
+
+This metric show the current status of a cluster resource. 
+
+A resource that previously was in the cluster but isn't anymore, will not monitored. Example:
+
+```ha_cluster_node_resources{managed="true",node_name="1b115",resource_name="cluster_md",role="started",status="active"} 1```
+
+The metric will absent and not `0`
+
+
+All the values are 1:1 with Pacemaker schema.
+
+- `managed`: indicates `true` or `false` if the resource is managed in cluster
+- `node_name`: name of node of cluster
+- `resource_name`: resource id/name of the CIB pacemaker
+- `role`:  allowed values `Started/Stopped/Master/Slave` or pending state `Starting/Stopping/Migrating/Promoting/Demoting` which are same as pacemaker roles for resources.
+- `status` allowed values `active/orphaned/blocked/failed/failureIgnored/` status of resource from pacemaker XML.
+           Additionaly for the same resource we can have a combination of status.
+
+Example:
+
+```
+ha_cluster_node_resources{managed="true",node_name="1b115",resource_name="cluster_md",role="started",status="active"} 1
+ha_cluster_node_resources{managed="true",node_name="1b115",resource_name="clvm",role="started",status="active"} 1
+ha_cluster_node_resources{managed="true",node_name="1b115",resource_name="dlm",role="started",status="active"} 1
+ha_cluster_node_resources{managed="true",node_name="1b115",resource_name="drbd_passive",role="master",status="active"} 1
+ha_cluster_node_resources{managed="true",node_name="1b115",resource_name="fs_cluster_md",role="started",status="active"} 1
+ha_cluster_node_resources{managed="true",node_name="1b115",resource_name="fs_drbd_passive",role="started",status="active"} 1
+ha_cluster_node_resources{managed="true",node_name="1b115",resource_name="stonith-sbd",role="started",status="active"} 1
+ha_cluster_node_resources{managed="true",node_name="1b115",resource_name="vg_cluster_md",role="started",status="active"} 1
+ha_cluster_node_resources{managed="true",node_name="1b211",resource_name="dlm",role="started",status="active"} 1
+ha_cluster_node_resources{managed="true",node_name="1b211",resource_name="fs_cluster_md",role="stopped",status="active"} 1
+ha_cluster_node_resources{managed="true",node_name="1b211",resource_name="vg_cluster_md",role="stopped",status="active"} 1
+```
+
+## ha_cluster_nodes
+
+- `node_name`: name of cluster node
+- `type`: allowed values  `online/standby/standby_onfail/maintanance/pending/unclean/shutdown/expected_up/dc/member/ping/remote/`. This are the possible type of pacemaker ha cluster
+
+Again here, when the resource is absent will be not showed. There is no `0` value, since it is a real snapshot from the HA cluster.
+Examples:
+```
+ha_cluster_nodes{node_name="1b115",type="dc"} 1
+ha_cluster_nodes{node_name="1b115",type="expected_up"} 1
+ha_cluster_nodes{node_name="1b115",type="member"} 1
+ha_cluster_nodes{node_name="1b115",type="online"} 1
+ha_cluster_nodes{node_name="1b211",type="expected_up"} 1
+ha_cluster_nodes{node_name="1b211",type="member"} 1
+ha_cluster_nodes{node_name="1b211",type="online"} 1
+```
+
+## ha_cluster_nodes_configured_total 
+
+Show the total number of configured noded in the HA cluster
+
+Example:
+
+```
+ha_cluster_nodes_configured_total 2
+```
+
+
+## ha_cluster_resources_configured_total 
+
+Show the total number of resource configured in HA cluster
+Example:
+```
+ha_cluster_resources_configured_total 14
+```
+
+
+# Corosync
+
+`TODO`
+
+# Drbd
+
+`TODO`@MalloZup
+
+# SBD
+
+`TODO`