Use /ping endpoint for readiness check

root/etc/s6-overlay/s6-rc.d/svc-sonarr/data/check

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+if [[ $(curl -sL "http://localhost:8989/ping" | jq -r '.status' 2>/dev/null) = "OK" ]]; then
+    exit 0
+else
+    exit 1
+fi

root/etc/s6-overlay/s6-rc.d/svc-sonarr/run

@@ -2,6 +2,6 @@
 # shellcheck shell=bash
 
 exec \
-    s6-notifyoncheck -d -n 300 -w 1000 -c "nc -z localhost 8989" \
+    s6-notifyoncheck -d -n 300 -w 1000 \
         cd /app/sonarr/bin s6-setuidgid abc /app/sonarr/bin/Sonarr \
         -nobrowser -data=/config