Added checking if block are absent

Author: feliam

composer/provisioning/prometheus/namada-alerts.yml

@@ -2,7 +2,7 @@ groups:
 - name: namada-validator-alerts
   rules:
   - alert: NamadaBlockHeightStalled
-    expr: rate(namada_block_height{ chain_id="$$CHAIN_ID$$" }[1m]) == 0
+    expr: (absent_over_time(namada_block_height{ chain_id="$$CHAIN_ID$$" }[1m]) or rate(namada_block_height{ chain_id="$$CHAIN_ID$$" }[1m]) == 0)
     labels:
       severity: critical
     annotations: