v-m: Scrape PiKVM metrics

PiKVM exports some rudimentary metrics, but requires authentication to
scrape them.  At the very least, this will provide alerting in case the
PiKVM systems go offline.

victoria-metrics/scrape.yml

@@ -513,3 +513,23 @@ scrape_configs:
     target_label: instance
   - target_label: __address__
     replacement: blackbox-exporter:9115
+
+- job_name: pikvm
+  scheme: https
+  metrics_path: /api/export/prometheus/metrics
+  tls_config:
+    ca_file: /run/dch-ca/dch-root-ca.crt
+  dns_sd_configs:
+  - names:
+    - pikvm-nvr2.mgmt.pyrocufflink.black
+    type: A
+    port: 443
+  basic_auth:
+    username: prometheus
+    password_file: /run/secrets/vmagent/pikvm.password
+  relabel_configs:
+  - source_labels: [__meta_dns_name, __meta_dns_srv_record_port]
+    separator: ':'
+    target_label: __address__
+  - source_labels: [__meta_dns_name]
+    target_label: instance