Implement DRBD monitoring

[MalloZup]

metric:

1. drbd Resource:

• ha_cluster_drbd_resource{resource_name="1-single-0", role="primary", volume="0", disk-state="uptodate", replication-state="etablished", peer-disk-state"uptodate"}

• ha_cluster_drbd_resource{resource_name="vg2", role="secondary", volume="0", disk-state="uptodate" replication-state="etablished", peer-disk-state"uptodate"}

• ha_cluster_drbd_resource{resource_name="vg2", role="secondary", volume="1", disk-state="outdated" replication-state="etablished", peer-disk-state"uptodate"}

---

drbdsetup status --json

[
{
  "name": "1-single-0",
  "node-id": 1,
  "role": "Primary",
  "suspended": false,
  "write-ordering": "flush",
  "devices": [
    {
      "volume": 0,
      "minor": 2,
      "disk-state": "UpToDate",
      "client": false,
      "quorum": true,
      "size": 409600,
      "read": 8457,
      "written": 536513,
      "al-writes": 4,
      "bm-writes": 0,
      "upper-pending": 0,
      "lower-pending": 0
    } ],
  "connections": [
    {
      "peer-node-id": 2,
      "name": "SLE15-sp1-gm-drbd1145296-node2",
      "connection-state": "Connected", 
      "congested": false,
      "peer-role": "Secondary",
      "ap-in-flight": 0,
      "rs-in-flight": 0,
      "peer_devices": [
        {
          "volume": 0,
          "replication-state": "Established",
          "peer-disk-state": "UpToDate",
          "peer-client": false,
          "resync-suspended": "no",
          "received": 8202,
          "sent": 534390,
          "out-of-sync": 0,
          "pending": 0,
          "unacked": 0,
          "has-sync-details": false,
          "has-online-verify-details": false,
          "percent-in-sync": 100.00
        } ]
    } ]
}
,```

[diegoakechi]

@MalloZup My suggestion is that we could split the metrics in a way where the values represent the states and the label really identify the attributes for filtering (disk, nodes, etc). For example:

# Use 0=Out of Sync, 1=UptoDate, 2=Syncing
ha_cluster_drbd_resource_disk_state{resource_name="1-single-0", role="primary", volume="0"} 1

# Use 0=Out of Sync, 1=UptoDate, 2=Syncing
ha_cluster_drbd_resource_disk_state{resource_name="1-single-0", role="primary", volume="0"} 1

ha_cluster_drbd_resource_written_bytes{resource_name="1-single-0", role="primary", volume="0" } 536513

[MalloZup]

small roadmap

1. disk_state metric as suggested

this will follow same schema as 1)
2) ha_cluster_drbd_resource_connection_state{resource_name="1-single-0", role="primary", volume="0" peer-node-id="2" peer-role="Secondary"} 1

[MalloZup]

done