Overview Templates

An overview template is a JSON file describing a war-room / cross-cutting dashboard composed from MQE-driven widgets on a 12-column grid. Overviews are independent of any single layer and are designed for the operator’s “is everything OK?” pane.

Horizon ships bundled overview templates, and an administrator customizes them in the Overview Templates admin page (/admin/overview-templates, under Dashboard setup) — a visual editor that saves a local draft and publishes to OAP with Check diff & push. You don’t hand-edit JSON on the page; the shape documented below is the stored format the editor reads and writes. Bundled examples:

  • Service Health — cross-layer service health + Kubernetes capacity summary.
  • Mesh — Istio data-plane services + pilot activity + Kubernetes.

Template shape (reference)

{
  "id": "services",
  "title": "Service Health",
  "description": "Cross-layer service traffic, latency, errors, and capacity.",
  "visibility": "public",
  "icon": "services",
  "order": 1,
  "layers": ["GENERAL", "MESH", "K8S_SERVICE"],
  "widgets": [
    { "type": "section-break", "title": "Service traffic", "cols": 12 },
    { ... metric widget ... },
    { ... kpi-tile ... },
    { "type": "section-break", "title": "Cluster capacity", "cols": 6 },
    { ... metric-composite ... }
  ]
}

Top-level fields

Field Type Default Notes
id string required Stable id, used in the route /overview/:id.
title string required Display title in the sidebar and page header.
description string — One-line description shown under the title.
visibility public | operate public Sidebar placement. operate puts the overview under the Operate group (admin-only by convention).
icon string — Sidebar icon name (from Horizon’s icon set).
order number — Sort order within the visibility bucket (lower = earlier).
layers string[] — Layer enums this overview aggregates. Optional — Horizon also unions in every widget’s layer field, so a dashboard created via “+ New” (no layers[]) gates correctly off its widgets alone. See Sidebar visibility below.
widgets array required Ordered widget list. The renderer iterates and lays out per the grid model.

Widget types

Six supported type values:

Type Renders
metric Single MQE scalar with optional unit.
topology Service-map snapshot for the configured layer.
section-break Visual row header; carries cols to override the grid column count for following widgets.
kpi-tile Compound tile: optional service count + N KPI rows.
alarms Active-alarm rail (60 min window).
metric-composite Mixed KPI grid — number tiles + progress-bar rows.

See Components → Overview Widgets for the per-widget detail.

Grid model

The overview renders on a CSS grid:

  • Per-section column count, default 12, set by the most recent section-break.cols.
  • Fixed row height 72 px.
  • Per-widget span (column width, 1–12) and rowSpan (row height, 1–8).
  • Gap 12 px between widgets.
  • Single-column responsive collapse below 1100 px viewport.

The 72 px row height is tuned for KPI tile content; widgets that need more vertical space (a small chart, a multi-row composite) use rowSpan: 2 or rowSpan: 3.

Widget shape (common fields)

Field Notes
id Unique within the dashboard.
title Card title (not used by section-break — uses title as the section header).
tip Optional one-line hover hint next to the title.
layer Layer key (UPPER_SNAKE). Used to scope MQE evaluation. Optional for section-break and alarms (alarms can scope server-side if the layer is set).
type One of metric, topology, section-break, kpi-tile, alarms, or metric-composite.
span Column span. Defaults vary per widget type.
rowSpan Row span. Defaults vary per widget type.
mqe, unit, aggregation Metric-specific fields.
cols Section-break column count for following widgets.
kpis, showCount, limit Type-specific fields described below.

OverviewKpi

Used by kpi-tile and metric-composite:

Field Notes
label Row label.
mqe Required when source === 'mqe' (the default).
unit Unit suffix.
aggregation sum for throughput / count; avg for ratios and rates.
style number (default) or progress-bar.
max Required when style === 'progress-bar' — the 100% value.
source mqe (default) or service-count — the latter reads the layer’s service count from the menu response instead of evaluating MQE.

Worked examples

metric widget

{
  "id": "total_rpm",
  "title": "Total RPM",
  "type": "metric",
  "layer": "GENERAL",
  "mqe": "sum(service_cpm)",
  "unit": "rpm",
  "aggregation": "sum",
  "span": 3,
  "rowSpan": 1
}

Single scalar tile. The MQE collapses to one number (here, sum over the time window).

kpi-tile with service count + two KPIs

{
  "id": "general_summary",
  "title": "General services",
  "type": "kpi-tile",
  "layer": "GENERAL",
  "showCount": true,
  "span": 4,
  "rowSpan": 3,
  "kpis": [
    {
      "label": "Apdex",
      "mqe": "avg(service_apdex/10000)",
      "aggregation": "avg",
      "style": "progress-bar",
      "max": 1
    },
    {
      "label": "P95",
      "mqe": "avg(service_percentile{p='95'})",
      "unit": "ms",
      "aggregation": "avg"
    }
  ]
}

showCount: true adds a service-count header row above the KPIs.

metric-composite — mixed number + bar grid

{
  "id": "k8s_summary",
  "title": "Cluster capacity & utilisation",
  "type": "metric-composite",
  "layer": "K8S",
  "span": 12,
  "rowSpan": 3,
  "kpis": [
    { "label": "Nodes", "mqe": "latest(k8s_cluster_node_total)", "aggregation": "avg" },
    { "label": "Pods",  "mqe": "latest(k8s_cluster_pod_total)",  "aggregation": "avg" },
    { "label": "CPU",
      "mqe": "k8s_cluster_cpu_cores_requests / k8s_cluster_cpu_cores * 100",
      "unit": "%", "aggregation": "avg",
      "style": "progress-bar", "max": 100 },
    { "label": "Memory",
      "mqe": "k8s_cluster_memory_requests / k8s_cluster_memory * 100",
      "unit": "%", "aggregation": "avg",
      "style": "progress-bar", "max": 100 }
  ]
}

The widget auto-splits KPIs:

  • number-style KPIs (Nodes, Pods) go into the count-tile row (auto-fit, min 100 px).
  • progress-bar-style or unit === '%' KPIs go into the bar grid (auto-fit, min 180 px).

This single widget replaces what used to be three separate hand-crafted widgets (k8s-service-count, pilot, service-count) — anything compound now goes through metric-composite.

section-break to start a new row

{ "type": "section-break", "title": "Cluster capacity", "cols": 6 }

Following widgets render in a 6-column grid (rather than 12) until the next section-break. Used for paired side-by-side panes.

alarms rail

{
  "id": "active_alarms",
  "title": "Active alarms (60 min)",
  "type": "alarms",
  "layer": "GENERAL",
  "limit": 10,
  "span": 4,
  "rowSpan": 4
}

Read-only — Horizon does not support acknowledge / close / silence operations. Alarm recovery is backend-automatic.

An overview entry appears in the sidebar only when at least one of its declared layers is currently reporting services. Declared layers come from two sources, unioned:

  • the explicit layers[] field on the dashboard, and
  • every widget.layer referenced by its widgets.

A dashboard with no layer reference on either side (no layers[] and no widgets with layer set — e.g. a future cross-layer “All” overview) is always shown.

This makes the sidebar honest: it stops listing a Services dashboard when nothing is reporting and lights it back up automatically when an agent / receiver does start, on the same 60-second cadence the menu refreshes. It also means a dashboard you create via “+ New” — which has no layers[] — gates correctly off its widgets without you having to maintain a separate list.

Admin Editor

Overview templates are editable at runtime via Dashboard setup → Overview templates (/admin/overview-templates, verb overview:write). Pick a dashboard from the filterable dropdown (title + id + sync status), then lay it out on a 12-column canvas: drag a widget to reorder, corner-drag to resize, click a widget to edit it in the right-hand drawer. Section breaks (“text widget” / line break) and the dashboard title are selectable too. The canvas shows sample data so you can judge layout; only the live page (Preview ▾) uses real OAP data.

Per-widget fields (the drawer shows only what the widget.type needs):

Type Fields shown
section-break title, cols
metric layer, title, tip, mqe, unit, aggregation, span, rowSpan
topology layer, title, tip, span, rowSpan
alarms layer, title, tip, limit, span, rowSpan
kpi-tile layer, title, tip, showCount, KPI rows (add / remove), span, rowSpan
metric-composite layer, title, tip, KPI rows (each a stacked card: label / source / MQE / unit / aggr / style / max), span, rowSpan

How edits flow: draft → preview → publish

Same model as layer templates: your edit lives in your browser, and the live page everyone sees stays on the published OAP version until you publish.

  1. Save (local). Stores your draft in this browser only; the dashboard is tagged local in the picker.
  2. Reset to ▾ loads the Bundled or Remote version into the canvas.
  3. Preview ▾ opens the real overview page in a new tab rendering Local / Bundled / Remote.
  4. Check diff & push shows a remote → local diff and publishes to OAP (create-or-update). Enabled only when your draft differs from remote.

A + New dashboard form (inside the picker) creates a dashboard the same way: it writes a local draft (id is the template name, must be unique) — edit and preview it, then Check diff & push publishes it to OAP. A pushed dashboard with no bundled default is remote-only; the picker, the live page, and the sidebar all show it.

A top banner summarizes state — Synced from OAP — N diverged, Y local — with Diverged / Local filters. Status chips per row: synced, diverged (OAP wins at render), remote-only, disabled (deleted), bundled.

Deleting a dashboard

OAP has no hard delete, so the Delete button next to the title soft-disables the dashboard on OAP (a disabled dashboard drops from the picker’s live state, the sidebar, and the live page). A dashboard that exists only as an unpublished local draft is removed from your browser instead. Either action is confirmed in a dialog first; deletion is irreversible from the UI, but a new dashboard can always be created with the same id.

Hot reload

Admin editor changes apply on the next overview refresh. Bundled file changes made outside Horizon require a BFF restart.

Common patterns

A war-room single-screen view

One overview, id: war-room, with layers: [ALL_YOUR_LAYERS], and:

  1. section-break “Health” + 4 × kpi-tile (one per critical layer with service-count + RPS / error-rate KPIs).
  2. section-break “Alarms” + 1 × alarms widget (span 12) showing every firing alarm.
  3. section-break “Capacity” + 1 × metric-composite (span 12) with cluster capacity.

Layout fits a 1440 px display above the fold; works on a wall projector at 1920 px.

A team-specific overview

visibility: operate, only granted to the team’s role via landingByRole:

landingByRole:
  payments-on-call: /overview/payments

The team lands directly on their own overview after login.

Replacing the old k8s / pilot / service-count widgets

Use metric-composite with one widget per cluster summary. The old per-feature widget types are no longer rendered — metric-composite is the unified shape.