version 5.1.16

- threshold.py: add _find_threshold() with suffix fallback so thresholds
  like ping_monitor.rtt_avg match ping_monitor.8_8_8_8_rtt_avg etc.;
  each pinged host keeps its own alert state
- hbdclass.py: format RTT as integer ms (round())
- live.html: JS RTT display rounded to nearest ms (Math.round)

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

README.md

@@ -267,6 +267,41 @@ All plugin metrics can be thresholded:
 - **Network**: errors_total, dropped packets, connection counts
 - **Nagios**: exit_code mapping (0=OK, 1=WARNING, 2=CRITICAL)
 
+### Per-Host Threshold Profiles
+
+Named threshold configurations let different hosts use different limits. A host's `threshold_config` can be a single name or a **list** — lists are applied left-to-right so profiles compose without duplication:
+
+```yaml
+threshold_configs:
+  default:
+    thresholds:
+      cpu_monitor:
+        cpu_percent: {warning: 80, critical: 90}
+      memory_monitor:
+        memory_percent: {warning: 85, critical: 95}
+
+  tight_cpu:           # override CPU limits only
+    thresholds:
+      cpu_monitor:
+        cpu_percent: {warning: 60, critical: 75}
+
+  db_disk:             # add a database partition check
+    thresholds:
+      disk_monitor:
+        partitions:
+          /var/lib/postgresql:
+            percent: {warning: 75, critical: 88}
+
+hosts:
+  web-01:
+    threshold_config: default          # single profile
+
+  db-01:
+    threshold_config: [tight_cpu, db_disk]   # layered: CPU override + extra disk check
+```
+
+Each named config's overrides are applied in order on top of the defaults. Metrics not mentioned in a profile are inherited unchanged.
+
 See [docs/THRESHOLD_ALERTING.md](docs/THRESHOLD_ALERTING.md) for comprehensive documentation including best practices, troubleshooting, and advanced configuration.
 
 ---

docs/THRESHOLD_ALERTING.md

@@ -814,34 +814,32 @@ Planned features:
 
 ## Multi-Threshold Configuration
 
-**New in version 2.0**: Support for multiple named threshold configurations with per-host mapping.
+Support for multiple named threshold configurations with per-host mapping and composable layering.
 
 ### Overview
 
 The multi-threshold feature allows you to:
-- Define multiple sets of threshold configurations
-- Map different hosts to different threshold sets
+- Define multiple named threshold configurations
+- Assign one or more configurations to each host
+- Compose configurations by layering — each named config's overrides are applied in order on top of the defaults
 - Use different sensitivity levels for different environments
-- Maintain a default configuration for unmapped hosts
 
 ### Configuration Structure
 
+Named configurations are defined under `threshold_configs`. Each host selects which ones to use via `threshold_config` in the `hosts` section (a string for a single config, or a list to layer multiple):
+
 ```yaml
-# Optional: Set the default configuration name (defaults to "default")
+# Optional: set the default configuration name (defaults to "default")
 default_threshold_config: "default"
 
-# Define multiple named threshold configurations
 threshold_configs:
-  # Configuration name 1
   default:
     thresholds:
-      # Standard threshold definitions
       cpu_monitor:
         cpu_percent:
           warning: 80.0
           critical: 90.0
 
-  # Configuration name 2
   high_sensitivity:
     thresholds:
       cpu_monitor:
@@ -849,7 +847,6 @@ threshold_configs:
           warning: 60.0
           critical: 75.0
 
-  # Configuration name 3
   low_sensitivity:
     thresholds:
       cpu_monitor:
@@ -857,14 +854,77 @@ threshold_configs:
           warning: 90.0
           critical: 95.0
 
-# Map specific hosts to specific configurations
-host_threshold_mapping:
-  prod-web-01: high_sensitivity
-  prod-web-02: high_sensitivity
-  dev-server-01: low_sensitivity
-  # Unmapped hosts use default_threshold_config
+hosts:
+  prod-web-01:
+    threshold_config: high_sensitivity   # single config
+
+  dev-server-01:
+    threshold_config: low_sensitivity
+
+  # Hosts with no threshold_config use default_threshold_config
 ```
 
+### Composable Configurations (list form)
+
+`threshold_config` can be a list. Configs are applied **left to right**: the defaults are the base, then each named config's overrides are layered on top. Later entries in the list win on any metric they define.
+
+```yaml
+threshold_configs:
+  default:
+    thresholds:
+      cpu_monitor:
+        cpu_percent: {warning: 80, critical: 90}
+      memory_monitor:
+        memory_percent: {warning: 85, critical: 95}
+      disk_monitor:
+        partitions:
+          /:
+            percent: {warning: 80, critical: 90}
+
+  # Tighter CPU limits for busy servers
+  high_cpu_load:
+    thresholds:
+      cpu_monitor:
+        cpu_percent: {warning: 60, critical: 75}
+
+  # Tighter disk limits for data-heavy servers
+  busy_disk:
+    thresholds:
+      disk_monitor:
+        partitions:
+          /:
+            percent: {warning: 70, critical: 85}
+
+hosts:
+  # Gets default thresholds only
+  web-01:
+    threshold_config: default
+
+  # Gets tighter CPU limits, default memory and disk
+  build-server:
+    threshold_config: high_cpu_load
+
+  # Layers both: tighter CPU AND tighter disk, default memory
+  db-01:
+    threshold_config: [high_cpu_load, busy_disk]
+
+  # Three layers: busy_disk overrides high_cpu_load if they conflict
+  storage-01:
+    threshold_config: [default, high_cpu_load, busy_disk]
+```
+
+**How layering works:**
+
+Starting from the `default` thresholds:
+
+| Layer | Applied config | Effect |
+|-------|---------------|--------|
+| Base  | `default` | all default thresholds |
+| +1    | `high_cpu_load` | cpu_percent overridden to 60/75 |
+| +2    | `busy_disk` | disk percent overridden to 70/85; cpu_percent stays at 60/75 |
+
+Each named config only overrides the metrics it explicitly defines. Metrics not mentioned in a config inherit from the layers beneath.
+
 ### Use Cases
 
 #### 1. Environment-Based Thresholds
@@ -887,11 +947,15 @@ threshold_configs:
           warning: 90.0   # More relaxed for dev
           critical: 98.0
 
-host_threshold_mapping:
-  prod-web-01: production
-  prod-web-02: production
-  dev-web-01: development
-  dev-web-02: development
+hosts:
+  prod-web-01:
+    threshold_config: production
+  prod-web-02:
+    threshold_config: production
+  dev-web-01:
+    threshold_config: development
+  dev-web-02:
+    threshold_config: development
 ```
 
 #### 2. Server Role-Based Thresholds
@@ -914,7 +978,7 @@ threshold_configs:
           warning: 70.0
           critical: 85.0
       memory_monitor:
-        percent:
+        memory_percent:
           warning: 90.0   # Databases can use high memory
           critical: 97.0
       disk_monitor:
@@ -927,17 +991,23 @@ threshold_configs:
   cache:
     thresholds:
       memory_monitor:
-        percent:
+        memory_percent:
           warning: 95.0   # Redis/Memcached can use very high memory
           critical: 99.0
 
-host_threshold_mapping:
-  web-01: webserver
-  web-02: webserver
-  db-01: database
-  db-02: database
-  redis-01: cache
-  memcached-01: cache
+hosts:
+  web-01:
+    threshold_config: webserver
+  web-02:
+    threshold_config: webserver
+  db-01:
+    threshold_config: database
+  db-02:
+    threshold_config: database
+  redis-01:
+    threshold_config: cache
+  memcached-01:
+    threshold_config: cache
 ```
 
 #### 3. Sensitivity Levels
@@ -952,7 +1022,7 @@ threshold_configs:
         partitions:
           /:
             percent:
-              warning: 70.0    # Very sensitive
+              warning: 70.0
               critical: 80.0
               hysteresis: 0.15
 
@@ -976,12 +1046,69 @@ threshold_configs:
               critical: 98.0
               hysteresis: 0.05
 
-host_threshold_mapping:
-  payment-gateway: critical
-  auth-server: critical
-  web-01: standard
-  web-02: standard
-  test-server: relaxed
+hosts:
+  payment-gateway:
+    threshold_config: critical
+  auth-server:
+    threshold_config: critical
+  web-01:
+    threshold_config: standard
+  web-02:
+    threshold_config: standard
+  test-server:
+    threshold_config: relaxed
+```
+
+#### 4. Composable Profiles
+
+Build host-specific thresholds by combining small, focused configs:
+
+```yaml
+threshold_configs:
+  # Baseline — everything at default levels
+  default:
+    thresholds:
+      cpu_monitor:
+        cpu_percent: {warning: 80, critical: 90}
+      memory_monitor:
+        memory_percent: {warning: 85, critical: 95}
+
+  # Overlay: tighter CPU only
+  tight_cpu:
+    thresholds:
+      cpu_monitor:
+        cpu_percent: {warning: 60, critical: 75}
+
+  # Overlay: tighter memory only
+  tight_memory:
+    thresholds:
+      memory_monitor:
+        memory_percent: {warning: 70, critical: 85}
+
+  # Overlay: extra disk partition for database servers
+  db_disk:
+    thresholds:
+      disk_monitor:
+        partitions:
+          /var/lib/postgresql:
+            percent: {warning: 75, critical: 88}
+
+hosts:
+  # Plain web server
+  web-01:
+    threshold_config: default
+
+  # Build server: tight CPU, default memory and disk
+  build-01:
+    threshold_config: tight_cpu
+
+  # Database: tight CPU + tight memory + extra disk partition
+  db-01:
+    threshold_config: [tight_cpu, tight_memory, db_disk]
+
+  # Replica database: tight memory + extra disk, normal CPU
+  db-02:
+    threshold_config: [tight_memory, db_disk]
 ```
 
 ### Backward Compatibility
@@ -1012,16 +1139,25 @@ threshold_configs:
 
 ### Configuration Priority
 
-1. **Host-specific mapping**: If host is in `host_threshold_mapping`, use that config
-2. **Default config**: Use `default_threshold_config` 
-3. **First alphabetically**: If default not found, use first config alphabetically
-4. **Legacy fallback**: If `threshold_configs` not present, use `thresholds`
+1. **Host `threshold_config` (list)**: Layer each named config's overrides left-to-right on top of the defaults
+2. **Host `threshold_config` (string)**: Use that single named config directly
+3. **`host_threshold_mapping`** (legacy): Same as above, string only
+4. **`default_threshold_config`**: Used for hosts with no mapping
+5. **First alphabetically**: If the default config is not found, use the first config alphabetically
+6. **Legacy `thresholds` section**: Used when `threshold_configs` is absent entirely
 
-### Example: Complete Multi-Threshold Setup
+### Backward Compatibility
 
-See `hbd/config_multi_threshold_example.yaml` for a complete example with:
-- 4 named configurations (default, high_sensitivity, low_sensitivity, database)
-- Host-to-config mappings for production, development, and test systems
-- Specialized database server thresholds
-- Custom display messages with plugin data
+The legacy `host_threshold_mapping` top-level key and the flat `thresholds` section are still fully supported:
+
+```yaml
+# Still works — equivalent to hosts: {prod-web-01: {threshold_config: high_sensitivity}}
+host_threshold_mapping:
+  prod-web-01: high_sensitivity
+
+# Still works — equivalent to threshold_configs: {default: {thresholds: ...}}
+thresholds:
+  cpu_monitor:
+    cpu_percent: {warning: 80, critical: 90}
+```
 

hbd/__init__.py

@@ -14,4 +14,4 @@ Install options:
 """
 
 __all__ = ["__version__"]
-__version__ = "5.1.12"
+__version__ = "5.1.16"

hbd/client/main.py

@@ -525,6 +525,13 @@ async def async_main(args, config):
     for sig in (signal.SIGTERM, signal.SIGINT):
         loop.add_signal_handler(sig, stop)
 
+    def _sighup():
+        global dorestart
+        dorestart = True
+        stop()
+
+    loop.add_signal_handler(signal.SIGHUP, _sighup)
+    
     # Start async tasks
     # Heartbeat senders (one per connection)
     for conn in connections:

hbd/client/plugins/zfs_monitor.py

@@ -0,0 +1,130 @@
+"""
+ZFS pool monitoring plugin for Heartbeat.
+
+Collects per-pool health, capacity, and cumulative I/O statistics via zpool(8).
+"""
+
+import asyncio
+import logging
+import shutil
+from typing import Any, Dict, List, Optional
+
+from hbd.client.plugin import MonitorPlugin
+
+logger = logging.getLogger(__name__)
+
+
+def _int(s: str) -> Optional[int]:
+    try:
+        return int(s.strip().rstrip("KMGTkBkmgt%x"))
+    except (ValueError, AttributeError):
+        return None
+
+
+def _float(s: str) -> Optional[float]:
+    try:
+        return float(s.strip().rstrip("%x"))
+    except (ValueError, AttributeError):
+        return None
+
+
+class ZFSMonitorPlugin(MonitorPlugin):
+    """Monitor ZFS pool health, capacity, and I/O statistics.
+
+    Collects per pool:
+    - health: ONLINE, DEGRADED, FAULTED, etc.
+    - size / alloc / free: total, allocated and free bytes
+    - capacity: percentage used (0-100)
+    - frag: fragmentation percentage
+    - dedup: deduplication ratio
+    - read_ops / write_ops: cumulative I/O operations since last boot/clear
+    - read_bw / write_bw: cumulative bytes transferred since last boot/clear
+
+    Configuration:
+        interval: collection interval in seconds (default: 300)
+        pools: list of pool names to monitor (default: all)
+    """
+
+    name = "zfs_monitor"
+    description = "ZFS pool health, capacity, and I/O statistics"
+    interval = 300
+
+    def __init__(self, config: Optional[Dict[str, Any]] = None):
+        super().__init__(config)
+        self.interval = self.config.get("interval", 300)
+        self._pools_filter: Optional[List[str]] = self.config.get("pools", None)
+
+    async def initialize(self) -> bool:
+        if not shutil.which("zpool"):
+            self.skip_reason = "zpool not found"
+            return False
+        logger.info("ZFS monitor initialized (interval: %ds)", self.interval)
+        return True
+
+    async def _run(self, *args: str) -> List[str]:
+        """Run a command and return its stdout lines, or [] on error."""
+        try:
+            proc = await asyncio.create_subprocess_exec(
+                *args,
+                stdout=asyncio.subprocess.PIPE,
+                stderr=asyncio.subprocess.DEVNULL,
+            )
+            stdout, _ = await asyncio.wait_for(proc.communicate(), timeout=15)
+            return stdout.decode(errors="replace").splitlines()
+        except (FileNotFoundError, asyncio.TimeoutError) as exc:
+            logger.warning("zfs_monitor: %s: %s", args[0], exc)
+            return []
+
+    async def _zpool_list(self) -> Dict[str, Dict]:
+        """Return per-pool health and capacity from `zpool list`."""
+        lines = await self._run(
+            "zpool", "list", "-H", "-p",
+            "-o", "name,health,size,alloc,free,cap,frag,dedup",
+        )
+        pools: Dict[str, Dict] = {}
+        for line in lines:
+            parts = line.split("\t")
+            if len(parts) < 8:
+                continue
+            name = parts[0].strip()
+            if self._pools_filter and name not in self._pools_filter:
+                continue
+            pools[name] = {
+                "health":   parts[1].strip(),
+                "size":     _int(parts[2]),
+                "alloc":    _int(parts[3]),
+                "free":     _int(parts[4]),
+                "capacity": _float(parts[5]),
+                "frag":     _float(parts[6]),
+                "dedup":    _float(parts[7]),
+            }
+        return pools
+
+    async def _zpool_iostat(self) -> Dict[str, Dict]:
+        """Return per-pool cumulative I/O counters from `zpool iostat`."""
+        lines = await self._run("zpool", "iostat", "-H", "-p")
+        io: Dict[str, Dict] = {}
+        for line in lines:
+            parts = line.split("\t")
+            if len(parts) < 7:
+                continue
+            name = parts[0].strip()
+            if not name or name.startswith(" "):
+                continue
+            io[name] = {
+                "read_ops": _int(parts[3]),
+                "write_ops": _int(parts[4]),
+                "read_bw":  _int(parts[5]),
+                "write_bw": _int(parts[6]),
+            }
+        return io
+
+    async def _collect_metrics(self) -> Dict[str, Any]:
+        pools, io = await asyncio.gather(self._zpool_list(), self._zpool_iostat())
+        for name, stats in io.items():
+            if name in pools:
+                pools[name].update(stats)
+        return {"pools": pools}
+
+
+plugin = ZFSMonitorPlugin

hbd/server/config.py

@@ -225,7 +225,7 @@ def get_watchhosts(config):
     hosts_config = config.get("hosts", {})
     if isinstance(hosts_config, dict):
         for host_name, host_attrs in hosts_config.items():
-            if isinstance(host_attrs, dict) and host_attrs.get("watch", False):
+            if isinstance(host_attrs, dict) and host_attrs.get("watch", True):
                 watchhosts.append(host_name)
     return watchhosts
 

hbd/server/hbdclass.py

@@ -95,7 +95,7 @@ class Connection:
         if not Null:
             d["addr"] = self.addr
             if self.rtts[-1]:
-                d["rtt"] = "%0.1f" % self.rtts[-1]
+                d["rtt"] = "%d" % round(self.rtts[-1])
             elif self.state == Connection.UNKNOWN:
                 d["rtt"] = ""
             else:
@@ -286,7 +286,7 @@ class Host:
             Host.hosts[name] = self
         self.num = num
         self.dyn = False
-        self.watched = False
+        self.watched = True
         self.upcount = 0
         self.interval = 0
         self.doesack = -1
@@ -304,6 +304,7 @@ class Host:
 
     def statedict(self):
         d = {}
+        d["raw_name"] = self.name
         d["name"] = self.name
         if self.dyn:
             d["name"] += "*"

hbd/server/http.py

@@ -258,7 +258,9 @@ async def start(
             extra_scripts=extra_scripts,
             hbd_version=hbd_version,
             hosts=[
-                hbdclass.Host.hosts[h].stateinfo() for h in sorted(hbdclass.Host.hosts)
+                hbdclass.Host.hosts[h].stateinfo()
+                for h in sorted(hbdclass.Host.hosts)
+                if _can_operate_host(current_user, hbdclass.Host.hosts[h])
             ],
             messages=data.msgs[-30:],
             current_user=current_user.to_dict() if current_user else None,
@@ -510,7 +512,7 @@ async def start(
         hosts_with_plugins = []
         for hostname in sorted(hbdclass.Host.hosts.keys()):
             host = hbdclass.Host.hosts[hostname]
-            if not _can_view_host(current_user, host):
+            if not _can_operate_host(current_user, host):
                 continue
             if host.plugin_data:
                 hosts_with_plugins.append({

hbd/server/settings.py

@@ -24,7 +24,7 @@ sensitive   bool  True when the raw value must never be shown
 # Credential field names that should always be masked.
 _SECRET_KEYS = frozenset({
     "password", "token", "user_key", "api_key", "secret",
-    "smtp_password", "smtp_user",
+    "smtp_password", "smtp_user", "api_password", "access_token",
 })
 
 _CHANNEL_TYPE_LABELS = {
@@ -181,6 +181,48 @@ def get_settings_sections(config: dict) -> list:
             "notification_channels": attrs.get("notification_channels", []),
         })
 
+    # ---- Threshold configurations -----------------------------------------
+    def _parse_metric_row(metric_path, metric_cfg):
+        if not isinstance(metric_cfg, dict):
+            return None
+        return {
+            "metric": metric_path,
+            "operator": metric_cfg.get("operator", ">"),
+            "warning": metric_cfg.get("warning"),
+            "critical": metric_cfg.get("critical"),
+            "hysteresis": metric_cfg.get("hysteresis"),
+            "count": metric_cfg.get("count", 1),
+            "enabled": metric_cfg.get("enabled", True),
+        }
+
+    threshold_config_list = []
+    raw_tconfigs = config.get("threshold_configs") or {}
+    if raw_tconfigs:
+        for cfg_name, cfg_data in sorted(raw_tconfigs.items()):
+            if not isinstance(cfg_data, dict):
+                continue
+            metrics = [
+                r for r in (
+                    _parse_metric_row(mp, mc)
+                    for mp, mc in (cfg_data.get("thresholds") or {}).items()
+                ) if r
+            ]
+            threshold_config_list.append({
+                "name": cfg_name,
+                "metrics": sorted(metrics, key=lambda m: m["metric"]),
+            })
+    elif config.get("thresholds"):
+        metrics = [
+            r for r in (
+                _parse_metric_row(mp, mc)
+                for mp, mc in config["thresholds"].items()
+            ) if r
+        ]
+        threshold_config_list.append({
+            "name": "default",
+            "metrics": sorted(metrics, key=lambda m: m["metric"]),
+        })
+
     # ---- Hosts summary ----------------------------------------------------
     hosts_list = []
     for hname, hcfg in (config.get("hosts") or {}).items():
@@ -188,7 +230,7 @@ def get_settings_sections(config: dict) -> list:
             continue
         hosts_list.append({
             "name": hname,
-            "watch": bool(hcfg.get("watch", False)),
+            "watch": bool(hcfg.get("watch", True)),
             "dyndns": bool(hcfg.get("dyndns", False)),
             "owner": hcfg.get("owner", ""),
             "managers": hcfg.get("managers", []),
@@ -312,6 +354,16 @@ def get_settings_sections(config: dict) -> list:
             "hosts": hosts_list,
             "fields": [],
         },
+        {
+            "id": "thresholds",
+            "title": "Threshold Configurations",
+            "description": "Named alert threshold sets. Each defines warning/critical levels per metric.",
+            "threshold_configs": threshold_config_list,
+            "fields": [
+                field("default_threshold_config", "Default config", "text",
+                      "Threshold config used for hosts with no explicit mapping."),
+            ],
+        },
         {
             "id": "runtime",
             "title": "Runtime",

hbd/server/templates/live.html

@@ -236,6 +236,8 @@
       color: #ff9800;
       font-weight: 700;
     }
+    #ntable a.host-link { color: inherit; text-decoration: none; }
+    #ntable a.host-link:hover { text-decoration: underline; }
   </style>
   <script type="text/javascript">
     var cnt = 0;
@@ -245,11 +247,13 @@
     var HBD_VERSION = "{{ hbd_version }}";
 
     function hostNameHtml(data) {
+      var rawName = data.raw_name || data.name.replace(/<[^>]+>/g, '').replace('*', '').trim();
       var nameHtml = data.name;
       if (!data.hbc_version || data.hbc_version !== HBD_VERSION) {
         nameHtml += ' 🥀';
       }
-      return data.dyn ? '<b>' + nameHtml + '</b>' : nameHtml;
+      var display = data.dyn ? '<b>' + nameHtml + '</b>' : nameHtml;
+      return '<a class="host-link" href="/plugins#' + encodeURIComponent(rawName) + '">' + display + '</a>';
     }
 
     function setup() {
@@ -404,7 +408,7 @@
         );
         if (data.connections[i].state == "up") {
           state = '<span class="state-up">up</span>';
-          latency = Number.parseFloat(data.connections[i].rtts[0]).toFixed(2);
+          latency = String(Math.round(Number.parseFloat(data.connections[i].rtts[0])));
         } else {
           if (data.connections[i].state == "unknown") {
             state = "";
@@ -511,7 +515,7 @@
           <tbody id="ntablebody">
             {% for host in hosts %}
             <tr class="{% if host.alert_critical_unacked > 0 or host.alert_critical_acked > 0 %}row-critical{% elif host.alert_warning_unacked > 0 or host.alert_warning_acked > 0 %}row-warning{% endif %}">
-              <td data-name="{{ host.name }}">{{ host.name }}{% if not host.hbc_version or host.hbc_version != hbd_version %} 🥀{% endif %}</td>
+              <td data-name="{{ host.name }}"><a class="host-link" href="/plugins#{{ host.raw_name | urlencode }}">{{ host.name }}{% if not host.hbc_version or host.hbc_version != hbd_version %} 🥀{% endif %}</a></td>
               <td style="text-align: center; color: #ff9800; font-weight: bold;">
                 {%- set warning_unacked = host.alert_warning_unacked -%}
                 {%- set warning_acked = host.alert_warning_acked -%}

hbd/server/templates/plugins.html

@@ -383,7 +383,7 @@
           </div>
 
           <div class="host-body">
-            {% set plugin_order = ['os_info','cpu_monitor','memory_monitor','disk_monitor','network_monitor','nagios_runner','filesystem_info'] %}
+            {% set plugin_order = ['os_info','cpu_monitor','memory_monitor','disk_monitor','network_monitor','zfs_monitor','nagios_runner','filesystem_info'] %}
             {% for plugin in plugin_order if plugin in host.plugins %}
             <div class="plugin-accordion collapsed"
                  data-hostname="{{ host.name }}"
@@ -673,6 +673,19 @@
             text = `${count} filesystem${count !== 1 ? 's' : ''}`;
             break;
           }
+          case 'zfs_monitor': {
+            const pools = d.pools || {};
+            const names = Object.keys(pools);
+            if (names.length === 0) { text = 'No pools'; break; }
+            const degraded = names.filter(n => pools[n].health && pools[n].health !== 'ONLINE');
+            text = names.map(n => {
+              const p = pools[n];
+              const cap = p.capacity != null ? ` ${p.capacity.toFixed(0)}%` : '';
+              return `${n}${cap}`;
+            }).join(' · ');
+            if (degraded.length) text += ` ⚠ ${degraded.map(n => pools[n].health).join(',')}`;
+            break;
+          }
           default:
             text = 'Loaded';
         }
@@ -694,6 +707,7 @@
           case 'memory_monitor': html = renderMemoryTable(cached.data); break;
           case 'disk_monitor':   html = renderDiskTables(cached.data); break;
           case 'network_monitor':html = renderNetworkTables(cached.data); break;
+          case 'zfs_monitor':    html = renderZfsTables(cached.data); break;
           case 'nagios_runner':  html = renderNagiosTable(cached.data); break;
           case 'filesystem_info':html = renderFilesystemTable(cached.data); break;
           default:               html = renderGenericTable(cached.data); break;
@@ -1024,6 +1038,66 @@
         return html;
       }
 
+      function renderZfsTables(d) {
+        const pools = d.pools || {};
+        const names = Object.keys(pools);
+        if (names.length === 0) return '<div class="no-data">No ZFS pools found</div>';
+
+        const healthCls = h => {
+          if (!h || h === 'ONLINE') return 'pct-ok';
+          if (h === 'DEGRADED') return 'pct-warn';
+          return 'pct-crit';
+        };
+
+        let pt = '<table class="data-table"><thead><tr>'
+          + '<th>Pool</th><th>Health</th>'
+          + '<th class="num">Size</th><th class="num">Used</th>'
+          + '<th class="num">Free</th><th class="num">Cap %</th>'
+          + '<th class="num">Frag %</th><th class="num">Dedup</th>'
+          + '</tr></thead><tbody>';
+        for (const name of names) {
+          const p = pools[name];
+          const cap = p.capacity != null ? p.capacity : 0;
+          const capCls = cap > 90 ? 'pct-crit' : cap > 75 ? 'pct-warn' : 'pct-ok';
+          pt += `<tr>
+            <td class="iface-name">${escHtml(name)}</td>
+            <td class="${healthCls(p.health)}">${escHtml(p.health || '—')}</td>
+            <td class="num">${formatBytes(p.size || 0)}</td>
+            <td class="num">${formatBytes(p.alloc || 0)}</td>
+            <td class="num">${formatBytes(p.free || 0)}</td>
+            <td class="num ${capCls}">${cap.toFixed(1)}%</td>
+            <td class="num">${p.frag != null ? p.frag.toFixed(1) + '%' : '—'}</td>
+            <td class="num">${p.dedup != null ? p.dedup.toFixed(2) + 'x' : '—'}</td>
+          </tr>`;
+        }
+        pt += '</tbody></table>';
+
+        const hasIo = names.some(n => pools[n].read_ops != null);
+        if (!hasIo) return pt;
+
+        let iot = '<table class="data-table"><thead><tr>'
+          + '<th>Pool</th>'
+          + '<th class="num">Read ops</th><th class="num">Write ops</th>'
+          + '<th class="num">Read BW</th><th class="num">Write BW</th>'
+          + '</tr></thead><tbody>';
+        for (const name of names) {
+          const p = pools[name];
+          iot += `<tr>
+            <td class="iface-name">${escHtml(name)}</td>
+            <td class="num">${p.read_ops != null ? p.read_ops.toLocaleString() : '—'}</td>
+            <td class="num">${p.write_ops != null ? p.write_ops.toLocaleString() : '—'}</td>
+            <td class="num">${p.read_bw != null ? formatBytes(p.read_bw) : '—'}</td>
+            <td class="num">${p.write_bw != null ? formatBytes(p.write_bw) : '—'}</td>
+          </tr>`;
+        }
+        iot += '</tbody></table>';
+
+        return `<div class="flex-tables">
+          <div><div class="table-section-label">Pools</div>${pt}</div>
+          <div><div class="table-section-label">I/O (cumulative)</div>${iot}</div>
+        </div>`;
+      }
+
       function renderGenericTable(d) {
         let html = '<table class="data-table"><thead><tr><th>Field</th><th>Value</th></tr></thead><tbody>';
         for (const [k, v] of Object.entries(d)) {
@@ -1082,6 +1156,19 @@
       // ── Init ────────────────────────────────────────────────────────────────
 
       document.addEventListener('DOMContentLoaded', () => {
+        // If a host fragment is in the URL, expand and scroll to that host;
+        // otherwise expand the first host as before.
+        const hash = window.location.hash;
+        if (hash) {
+          const hostname = decodeURIComponent(hash.slice(1));
+          const card = document.querySelector(`.host-card[data-hostname="${hostname}"]`);
+          if (card) {
+            card.classList.remove('collapsed');
+            fetchHostGlance(hostname);
+            setTimeout(() => card.scrollIntoView({ behavior: 'smooth', block: 'start' }), 150);
+            return;
+          }
+        }
         const first = document.querySelector('.host-card');
         if (first) {
           first.classList.remove('collapsed');

hbd/server/templates/settings.html

@@ -254,6 +254,17 @@
     .host-bool { text-align: center; }
     .dot-yes { color: #2e7d32; font-size: 1.1em; }
     .dot-no  { color: #ddd;    font-size: 1.1em; }
+
+    /* ---- Threshold configurations ---- */
+    .thresh-config { margin: 12px 20px 20px; }
+    .thresh-config-name {
+      font-weight: 600; font-size: 0.9em; color: #1a237e;
+      margin-bottom: 6px;
+    }
+    .mini-table .warn  { color: #e65100; font-weight: 600; }
+    .mini-table .crit  { color: #b71c1c; font-weight: 600; }
+    .mini-table .dim   { color: #aaa; }
+    .mini-table .metric-path { font-family: monospace; font-size: 0.88em; }
   </style>
 
   <body>
@@ -394,6 +405,49 @@
             {% endif %}
             {% endif %}
 
+            {# ---- Threshold configurations section ---- #}
+            {% if section.id == "thresholds" %}
+            {% if section.threshold_configs %}
+            {% for tc in section.threshold_configs %}
+            <div class="thresh-config">
+              <div class="thresh-config-name">{{ tc.name }}</div>
+              {% if tc.metrics %}
+              <div style="overflow-x: auto;">
+                <table class="mini-table">
+                  <thead>
+                    <tr>
+                      <th>Metric</th>
+                      <th>Op</th>
+                      <th>Warning</th>
+                      <th>Critical</th>
+                      <th>Hysteresis</th>
+                      <th>Count</th>
+                    </tr>
+                  </thead>
+                  <tbody>
+                    {% for m in tc.metrics %}
+                    <tr {% if not m.enabled %} style="opacity:0.45"{% endif %}>
+                      <td class="metric-path">{{ m.metric }}</td>
+                      <td>{{ m.operator or '>' }}</td>
+                      <td class="warn">{{ m.warning if m.warning is not none else '—' }}</td>
+                      <td class="crit">{{ m.critical if m.critical is not none else '—' }}</td>
+                      <td class="dim">{{ '%.0f%%' % (m.hysteresis * 100) if m.hysteresis else '—' }}</td>
+                      <td class="dim">{{ m.count }}</td>
+                    </tr>
+                    {% endfor %}
+                  </tbody>
+                </table>
+              </div>
+              {% else %}
+              <span class="val-empty">No thresholds defined.</span>
+              {% endif %}
+            </div>
+            {% endfor %}
+            {% else %}
+            <div class="field-row"><span class="val-empty">No threshold configurations defined.</span></div>
+            {% endif %}
+            {% endif %}
+
             {# ---- Hosts section ---- #}
             {% if section.id == "hosts" %}
             {% if section.hosts %}

hbd/server/threshold.py

@@ -9,10 +9,11 @@ This module provides a flexible threshold checking system that:
 - Supports multiple comparison operators
 """
 
+import asyncio
 import logging
 import time
 from enum import Enum
-from typing import Dict, Any, Optional, Tuple, Callable
+from typing import Dict, List, Any, Optional, Tuple, Callable
 from . import notify as notify_mod
 from .config import THRESHOLD_DEFAULTS
 
@@ -328,14 +329,17 @@ class ThresholdChecker:
             renotify_interval: Seconds between repeat notifications (default: 1 hour)
             journal: Optional MessageJournal instance for logging threshold events
         """
-        # Named threshold configurations: {config_name: {metric_path: ThresholdConfig}}
+        # Named threshold configurations (pre-merged: defaults + overrides): {config_name: {metric_path: ThresholdConfig}}
         self.threshold_configs = {}
 
+        # Raw overrides only for each named config (no defaults baked in): {config_name: {metric_path: ThresholdConfig}}
+        self.threshold_raw_configs: Dict[str, Dict[str, ThresholdConfig]] = {}
+
         # Single threshold set for backward compatibility: {metric_path: ThresholdConfig}
         self.thresholds = {}
 
-        # Host to config name mapping: {host_name: config_name}
-        self.host_config_mapping = {}
+        # Host to ordered list of config names: {host_name: [config_name, ...]}
+        self.host_config_mapping: Dict[str, List[str]] = {}
 
         # Default config name to use when no mapping exists
         self.default_config = "default"
@@ -372,6 +376,7 @@ class ThresholdChecker:
         
         # Clear old configuration
         self.threshold_configs.clear()
+        self.threshold_raw_configs.clear()
         self.thresholds.clear()
         self.host_config_mapping.clear()
         self.grace_seconds = float(config.get("grace", 2))
@@ -424,9 +429,10 @@ class ThresholdChecker:
                         self._parse_plugin_thresholds(plugin_name, plugin_thresholds, target_dict=effective_defaults)
 
         self.threshold_configs["default"] = dict(effective_defaults)
+        self.threshold_raw_configs["default"] = {}
         logger.info("Registered 'default' threshold config with %d metrics", len(effective_defaults))
 
-        # Parse each named configuration, seeding it with effective_defaults first
+        # Parse each named configuration
         for config_name, config_data in threshold_configs.items():
             if config_name == "default":
                 continue  # already handled above
@@ -440,33 +446,41 @@ class ThresholdChecker:
                 continue
 
             logger.info("Parsing threshold configuration: %s", config_name)
-            self.threshold_configs[config_name] = dict(effective_defaults)
 
+            # Raw overrides only (used for multi-config layering)
+            raw_overrides: Dict[str, ThresholdConfig] = {}
             thresholds_config = config_data["thresholds"]
             for plugin_name, plugin_thresholds in thresholds_config.items():
-                if not isinstance(plugin_thresholds, dict):
-                    continue
+                if isinstance(plugin_thresholds, dict):
+                    self._parse_plugin_thresholds(plugin_name, plugin_thresholds, target_dict=raw_overrides)
+            self.threshold_raw_configs[config_name] = raw_overrides
 
-                self._parse_plugin_thresholds(
-                    plugin_name,
-                    plugin_thresholds,
-                    target_dict=self.threshold_configs[config_name]
-                )
+            # Pre-merged version (defaults + overrides) for single-config fast path
+            self.threshold_configs[config_name] = dict(effective_defaults)
+            self.threshold_configs[config_name].update(raw_overrides)
 
-        # Parse host to config mapping from two possible sources
-        # 1. New format: hosts section with threshold_config attribute
+        # Parse host → config list mapping from two possible sources
+
+        def _normalise(value) -> List[str]:
+            """Accept a string or list; always return a list."""
+            if isinstance(value, list):
+                return [str(v) for v in value]
+            return [str(value)]
+
+        # 1. hosts section with threshold_config attribute (string or list)
         if "hosts" in config:
             hosts_config = config["hosts"]
             if isinstance(hosts_config, dict):
                 for host_name, host_attrs in hosts_config.items():
                     if isinstance(host_attrs, dict) and "threshold_config" in host_attrs:
-                        self.host_config_mapping[host_name] = host_attrs["threshold_config"]
+                        self.host_config_mapping[host_name] = _normalise(host_attrs["threshold_config"])
 
-        # 2. Legacy format: host_threshold_mapping section (for backward compatibility)
+        # 2. Legacy host_threshold_mapping section (string values only)
         if "host_threshold_mapping" in config:
             legacy_mapping = config.get("host_threshold_mapping", {})
             if isinstance(legacy_mapping, dict):
-                self.host_config_mapping.update(legacy_mapping)
+                for host_name, value in legacy_mapping.items():
+                    self.host_config_mapping[host_name] = _normalise(value)
         
         # Set default config (first one alphabetically or explicitly set)
         self.default_config = config.get("default_threshold_config", "default")
@@ -664,7 +678,10 @@ class ThresholdChecker:
         )
     
     def get_thresholds_for_host(self, host_name: str) -> Dict[str, ThresholdConfig]:
-        """Get the appropriate threshold configuration for a host.
+        """Get the effective threshold configuration for a host.
+
+        When threshold_config is a list, configs are applied left-to-right on top
+        of the default thresholds so earlier entries can be overridden by later ones.
 
         Args:
             host_name: Name of the host
@@ -676,23 +693,40 @@ class ThresholdChecker:
         if self.thresholds and not self.threshold_configs:
             return self.thresholds
 
-        # Multi-config mode: look up host-specific configuration
-        if self.threshold_configs:
-            config_name = self.host_config_mapping.get(host_name, self.default_config)
+        if not self.threshold_configs:
+            return {}
 
-            if config_name in self.threshold_configs:
-                return self.threshold_configs[config_name]
-            else:
+        config_names = self.host_config_mapping.get(host_name)
+
+        # No host-specific mapping → return pre-merged default
+        if not config_names:
+            return self.threshold_configs.get(self.default_config, {})
+
+        # Single config → fast path using pre-merged copy
+        if len(config_names) == 1:
+            name = config_names[0]
+            if name in self.threshold_configs:
+                return self.threshold_configs[name]
             logger.warning(
                 "Threshold config '%s' not found for host '%s', using default '%s'",
-                    config_name,
-                    host_name,
-                    self.default_config
+                name, host_name, self.default_config,
             )
             return self.threshold_configs.get(self.default_config, {})
 
-        # No thresholds configured
-        return {}
+        # Multiple configs → start from defaults, layer raw overrides in order
+        result = dict(self.threshold_configs.get(self.default_config, {}))
+        for name in config_names:
+            if name == self.default_config:
+                continue  # defaults already the base
+            raw = self.threshold_raw_configs.get(name)
+            if raw is None:
+                logger.warning(
+                    "Threshold config '%s' not found for host '%s', skipping",
+                    name, host_name,
+                )
+            else:
+                result.update(raw)
+        return result
     
     def check_value(
         self,
@@ -769,6 +803,29 @@ class ThresholdChecker:
             self._check_pending_or_renotify(host_name, alert_state, metric_path, value, threshold, None)
 
         return None
+    def _find_threshold(
+        self, thresholds: Dict[str, "ThresholdConfig"], metric_path: str
+    ) -> Optional["ThresholdConfig"]:
+        """Return the threshold for *metric_path*, falling back to suffix matches.
+
+        Allows generic thresholds like ``ping_monitor.rtt_avg`` to match
+        fully-qualified paths like ``ping_monitor.8_8_8_8_rtt_avg``.
+        The exact match is always tried first; then successive leading
+        underscore-delimited segments are stripped from the field name until
+        a match is found or no segments remain.
+        """
+        if metric_path in thresholds:
+            return thresholds[metric_path]
+        plugin, sep, field = metric_path.partition(".")
+        if not sep:
+            return None
+        parts = field.split("_")
+        for i in range(1, len(parts)):
+            candidate = plugin + "." + "_".join(parts[i:])
+            if candidate in thresholds:
+                return thresholds[candidate]
+        return None
+
     def check_plugin_data(
         self,
         host_name: str,
@@ -797,11 +854,10 @@ class ThresholdChecker:
         for metric_name, value in data.items():
             metric_path = f"{plugin_name}.{metric_name}"
             
-            if metric_path not in thresholds:
+            threshold = self._find_threshold(thresholds, metric_path)
+            if threshold is None:
                 continue
             
-            threshold = thresholds[metric_path]
-            
             # Get or create alert state
             if metric_path not in alert_states:
                 alert_states[metric_path] = AlertState(metric_path)
@@ -987,6 +1043,11 @@ class ThresholdChecker:
         value: Any,
     ):
         """Send notification and log to journal/eventlog."""
+        from . import hbdclass
+        host = hbdclass.Host.hosts.get(host_name)
+        if host is not None and not host.watched:
+            eventlog(host_name, lvl, message, service="threshold")
+            return
         asyncio.get_event_loop().create_task(notify_mod.send_notification(
             host_name,
             notify_mod.Notification(
@@ -999,7 +1060,6 @@ class ThresholdChecker:
         # Log to journal
         if self.journal is not None:
             try:
-                import asyncio
                 loop = asyncio.get_event_loop()
                 loop.create_task(self.journal.log_threshold_event(
                     host_name=host_name,
@@ -1076,7 +1136,9 @@ class ThresholdChecker:
     ) -> None:
         """Handle a state-change transition with grace-period logic.
 
-        Transitioning INTO alert: defers the notification for grace_seconds.
+        Transitioning INTO alert (worsening): defers the notification for grace_seconds.
+        De-escalation within alert states (e.g. CRITICAL→WARNING): no new notification;
+          the metric is still alerting so no RECOVER was sent.
         Transitioning TO OK:
           - Still in grace window (pending_since set): suppresses both the alert
             and the recovery — the spike never warranted a page.
@@ -1096,12 +1158,20 @@ class ThresholdChecker:
                 alert_state.pending_since = None
             else:
                 self._send_notification(host_name, lvl, message, metric_path, old_level, new_level, value)
-        else:
+        elif new_level.value > old_level.value:
+            # Worsening (OK→WARNING, OK→CRITICAL, WARNING→CRITICAL): schedule notification.
             alert_state.pending_since = time.time()
             logger.debug(
                 "Alert deferred (%.0fs grace): %s on %s = %s",
                 self.grace_seconds, metric_path, host_name, value,
             )
+        else:
+            # De-escalation within alert states (e.g. CRITICAL→WARNING): metric is still
+            # alerting but did not recover, so no new notification.
+            logger.debug(
+                "De-escalation %s→%s for %s on %s, no notification",
+                old_level.name, new_level.name, metric_path, host_name,
+            )
 
     def _check_pending_or_renotify(
         self,
@@ -1191,6 +1261,9 @@ class ThresholdChecker:
             else:
                 message = f"REMINDER ({alert_state.level.name}): {host_name} - {metric_path} = {value} (ongoing for {int(now - alert_state.since)}s)"
             
+            from . import hbdclass
+            host = hbdclass.Host.hosts.get(host_name)
+            if host is None or host.watched:
                 asyncio.get_event_loop().create_task(notify_mod.send_notification(
                     host_name,
                     notify_mod.Notification(
@@ -1199,9 +1272,9 @@ class ThresholdChecker:
                         level=alert_state.level.name,
                     ),
                 ))
+                logger.info("Re-notification sent: %s", message)
             alert_state.last_notification = now
             alert_state.notification_count += 1
-            logger.info("Re-notification sent: %s", message)
     
     def get_active_alerts(self, alert_states: Dict[str, AlertState]) -> list:
         """

hbd/server/udp.py

@@ -211,6 +211,7 @@ def _make_timer_callbacks(uname, host, ctx):
         connection.newstate(connection.__class__.OVERDUE, now, cfg.get("grace", 2))
         msg = f"{connection.afam} overdue"
         eventlog(uname, "CRITICAL", msg)
+        if host.watched:
             asyncio.create_task(notify_mod.send_notification(
                 uname,
                 notify_mod.Notification(title=f"[CRITICAL] {uname}", body=msg, level="CRITICAL"),
@@ -407,6 +408,7 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
 
     if res:
         eventlog(uname, "WARNING", res)
+        if host.watched:
             asyncio.create_task(notify_mod.send_notification(
                 uname,
                 notify_mod.Notification(title=f"[WARNING] {uname}", body=res, level="WARNING"),
@@ -420,6 +422,7 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
 
     if boot:
         eventlog(uname, "INFO", "booted")
+        if host.watched:
             asyncio.create_task(notify_mod.send_notification(
                 uname,
                 notify_mod.Notification(title=f"[INFO] {uname}", body=f"{host.name} booted", level="INFO"),
@@ -437,9 +440,14 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
         if not newh:
             if d == 0 or lasts == "unknown":
                 m = "%s is up" % (conn.afam)
+            elif d < 4:
+                # Transient blip (likely client restart) — skip log and notification
+                m = None
             else:
                 m = "%s back after being %s for %s" % (conn.afam, lasts, dur(d))
+            if m:
                 eventlog(uname, "RECOVER", m)
+                if host.watched:
                     asyncio.create_task(notify_mod.send_notification(
                         uname,
                         notify_mod.Notification(title=f"[RECOVER] {uname}", body=m, level="RECOVER"),
@@ -453,6 +461,7 @@ def handle_datagram(msg: dict, addr, transport, ctx: dict):
     if shutdown:
         m = "%s shutdown" % conn.afam
         eventlog(uname, "INFO", m)
+        if host.watched:
             asyncio.create_task(notify_mod.send_notification(
                 uname,
                 notify_mod.Notification(title=f"[INFO] {uname}", body=m, level="INFO"),

hbd/server/ws.py

@@ -13,7 +13,8 @@ from . import data
 
 logger = logging.getLogger(__name__)
 
-_connections: set = set()
+# Map of WebSocket → User object (or None when auth is disabled)
+_connections: dict = {}
 _loop: Optional[asyncio.AbstractEventLoop] = None
 _get_hosts: Optional[Callable[[], Iterable]] = None
 _verbose: bool = False
@@ -34,22 +35,52 @@ def setup(
     _verbose = verbose
 
 
+def _user_can_see_host(user, host_name: str) -> bool:
+    """Return True if *user* may see updates for *host_name* (manager or higher)."""
+    from . import hbdclass, users as users_mod
+    if user is None or not users_mod.users_enabled():
+        return True
+    if user.admin:
+        return True
+    host = hbdclass.Host.hosts.get(host_name)
+    if host is None:
+        return False
+    return host.is_manager(user.username)
+
+
+def _get_token(request) -> str:
+    """Extract session token from request (mirrors logic in http.py)."""
+    auth = request.headers.get("Authorization", "")
+    if auth.startswith("Bearer "):
+        return auth[7:].strip()
+    token = request.headers.get("X-Auth-Token", "")
+    if token:
+        return token
+    return request.cookies.get("hbd_session", "")
+
+
 async def handler(request):
     """aiohttp WebSocket upgrade handler — register as GET /ws."""
     from aiohttp import web
+    from . import users as users_mod
 
     ws = web.WebSocketResponse()
     await ws.prepare(request)
 
-    _connections.add(ws)
+    token = _get_token(request)
+    user = users_mod.get_session_user(token) if token else None
+
+    _connections[ws] = user
     remote = request.remote
     logger.info("WebSocket connected from %s", remote)
 
     try:
-        # Send current host state to the new client
+        # Send current host state, filtered to hosts this user may see
         if _get_hosts:
             try:
                 for h in list(_get_hosts()):
+                    host_name = h.get("raw_name") or h.get("name", "")
+                    if _user_can_see_host(user, host_name):
                         await ws.send_str(json.dumps({"type": "host", "data": h}))
             except Exception as e:
                 logger.error("Error sending initial hosts: %s", e)
@@ -74,7 +105,7 @@ async def handler(request):
     except Exception as e:
         logger.exception("WebSocket handler error from %s: %s", remote, e)
     finally:
-        _connections.discard(ws)
+        _connections.pop(ws, None)
         logger.info("WebSocket disconnected from %s", remote)
 
     return ws
@@ -83,25 +114,37 @@ async def handler(request):
 def broadcast(typ: str, payload) -> bool:
     """Thread-safe broadcast to all connected WebSocket clients.
 
+    For host and plugin updates, only sends to clients whose user has
+    manager-or-higher access to that host.  Other message types are
+    broadcast to all clients.
+
     Can be called from any thread; schedules sends on the event loop.
     Returns False if the loop is not running yet.
     """
     if not _loop:
         return False
+
+    # Determine the host name for access-filtered message types
+    host_name: Optional[str] = None
+    if typ in ("host", "plugin"):
+        host_name = payload.get("raw_name") or payload.get("host") or payload.get("name")
+
     jmsg = json.dumps({"type": typ, "data": payload})
 
     async def _send_all():
         dead = set()
-        for ws in list(_connections):
+        for ws, user in list(_connections.items()):
             try:
-                if not ws.closed:
-                    await ws.send_str(jmsg)
-                else:
+                if ws.closed:
                     dead.add(ws)
+                    continue
+                if host_name is not None and not _user_can_see_host(user, host_name):
+                    continue
+                await ws.send_str(jmsg)
             except Exception:
                 dead.add(ws)
         for ws in dead:
-            _connections.discard(ws)
+            _connections.pop(ws, None)
 
     asyncio.run_coroutine_threadsafe(_send_all(), _loop)
     return True

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "hbd"
-version = "5.1.12"
+version = "5.1.16"
 description = "Heartbeat monitoring system — client (hbc) and server (hbd)"
 readme = "README.md"
 requires-python = ">=3.11"

scripts/hbc_mini.py

@@ -41,7 +41,7 @@ from pathlib import Path
 from typing import Any, Dict, List, Optional, Tuple
 
 # updated by scripts/bumpminor.sh
-__version__ = "5.1.12"
+__version__ = "5.1.16"
 
 # ---------------------------------------------------------------------------
 # Protocol  (mirrors hbd/common/proto.py)
@@ -1066,6 +1066,13 @@ async def _async_main(args, cfg: Dict[str, Any]) -> int:
     for sig in (signal.SIGTERM, signal.SIGINT):
         loop.add_signal_handler(sig, _stop)
 
+    def _sighup():
+        global _dorestart
+        _dorestart = True
+        _stop()
+
+    loop.add_signal_handler(signal.SIGHUP, _sighup)
+
     for conn in connections:
         _active_tasks.append(asyncio.create_task(_heartbeat_sender(conn, interval)))