Extend monitoring and update portfolio

Add hostmetrics receiver and OTel Collector telemetry, and move
Alertmanager and Blackbox scraping to the collector. Raise collector
memory limits, restrict Blackbox to HTTP 200, and add collector and
Caddy down alerts with inhibition. Update portfolio title and copy.

otel-collector/config.yaml

@@ -3,6 +3,17 @@ receivers:
     protocols:
       http:
         endpoint: 0.0.0.0:4318
+  hostmetrics:
+    root_path: /hostfs
+    collection_interval: 10s
+    scrapers:
+      cpu:
+      memory:
+      disk:
+      filesystem:
+      network:
+      load:
+      processes:
   prometheus:
     config:
       scrape_configs:
@@ -18,11 +29,32 @@ receivers:
           scrape_interval: 10s
           static_configs:
             - targets: ['herald:9100']
+        - job_name: alertmanager
+          scrape_interval: 10s
+          static_configs:
+            - targets: ['alertmanager:9093']
+        - job_name: blackbox_http
+          scrape_interval: 10s
+          metrics_path: /probe
+          params:
+            module: [http_2xx]
+          static_configs:
+            - targets:
+              - https://www.qpismont.fr
+              - https://gitea.qpismont.fr
+              - https://woodpecker.qpismont.fr
+          relabel_configs:
+            - source_labels: [__address__]
+              target_label: __param_target
+            - source_labels: [__param_target]
+              target_label: instance
+            - target_label: __address__
+              replacement: blackbox_exporter:9115
 
 processors:
   memory_limiter:
     check_interval: 5s
-    limit_mib: 200
+    limit_mib: 400
     spike_limit_mib: 50
   batch:
     timeout: 10s
@@ -35,12 +67,20 @@ exporters:
     endpoint: http://tempo:4318
 
 service:
+  telemetry:
+    metrics:
+      readers:
+        - pull:
+            exporter:
+              prometheus:
+                host: 0.0.0.0
+                port: 8888
   pipelines:
     metrics:
-      receivers: [otlp, prometheus]
+      receivers: [otlp, prometheus, hostmetrics]
       processors: [memory_limiter, batch]
       exporters: [prometheusremotewrite]
     traces:
       receivers: [otlp]
       processors: [memory_limiter, batch]
-      exporters: [otlphttp/tempo]
+      exporters: [otlphttp/tempo]