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Y0lan/gist:0a84a1d2af1a92ad19a2a2b28d06723d

Created April 10, 2026 04:55
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gistfile1.txt
<!DOCTYPE html>
<html lang="fr">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>GKE Balloon Pods: du niveau 5 ans au niveau expert</title>
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link href="https://fonts.googleapis.com/css2?family=Fraunces:opsz,wght@9..144,400;9..144,700;9..144,900&family=DM+Sans:ital,wght@0,400;0,500;0,600;0,700;1,400&family=JetBrains+Mono:wght@400;500&display=swap" rel="stylesheet">
<style>
:root {
--bg-1: #f5efe2;
--bg-2: #fffaf0;
--paper: rgba(255, 252, 246, 0.92);
--ink: #1e2f2f;
--muted: #4a6262;
--subtle: #7a9494;
--line: rgba(30, 47, 47, 0.10);
--line-strong: rgba(30, 47, 47, 0.18);
--gold: #f4bd43;
--gold-2: #ffe3a0;
--gold-bg: rgba(244, 189, 67, 0.12);
--red: #e1634e;
--red-2: #ffb2a0;
--red-bg: rgba(225, 99, 78, 0.10);
--green: #1b8c6f;
--green-2: #b7eddc;
--green-bg: rgba(27, 140, 111, 0.08);
--blue: #1d5ae8;
--blue-2: #d8e5ff;
--blue-bg: rgba(29, 90, 232, 0.06);
--node: #fff5de;
--node-edge: #e7c269;
--shadow: 0 20px 60px rgba(34, 44, 50, 0.10);
--shadow-sm: 0 4px 16px rgba(34, 44, 50, 0.08);
--radius-xl: 28px;
--radius-lg: 20px;
--radius-md: 14px;
--radius-sm: 10px;
--font-display: "Fraunces", "Georgia", serif;
--font-body: "DM Sans", "Avenir Next", "Segoe UI", sans-serif;
--font-mono: "JetBrains Mono", "SFMono-Regular", "Consolas", monospace;
}
* { box-sizing: border-box; margin: 0; }
body {
font-family: var(--font-body);
color: var(--ink);
background:
radial-gradient(ellipse at 8% 6%, rgba(255, 231, 179, 0.55), transparent 22rem),
radial-gradient(ellipse at 92% 8%, rgba(183, 237, 220, 0.6), transparent 24rem),
radial-gradient(ellipse at 50% 80%, rgba(216, 229, 255, 0.3), transparent 30rem),
linear-gradient(180deg, var(--bg-1), var(--bg-2));
min-height: 100vh;
}
.wrap {
width: min(1200px, calc(100% - 2rem));
margin: 0 auto;
padding: 2rem 0 5rem;
display: grid;
gap: 1.25rem;
}
/* --- Cards --- */
.card {
background: var(--paper);
border: 1px solid var(--line);
border-radius: var(--radius-xl);
box-shadow: var(--shadow);
backdrop-filter: blur(12px);
padding: 2rem;
}
/* --- Typography --- */
h1 {
font-family: var(--font-display);
font-size: clamp(2.4rem, 5vw, 4rem);
line-height: 1.0;
font-weight: 900;
letter-spacing: -0.02em;
max-width: 14ch;
margin-bottom: 1.2rem;
}
h2 {
font-family: var(--font-display);
font-size: 1.55rem;
font-weight: 700;
margin-bottom: 1rem;
line-height: 1.2;
}
h3 {
font-size: 1.05rem;
font-weight: 700;
margin-bottom: 0.5rem;
}
p { margin-top: 0; }
.mono { font-family: var(--font-mono); font-size: 0.9em; }
a { color: var(--blue); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }
/* --- Hero --- */
.hero {
position: relative;
overflow: hidden;
}
.hero::before, .hero::after {
content: "";
position: absolute;
border-radius: 999px;
pointer-events: none;
}
.hero::before {
width: 16rem; height: 16rem;
right: -5rem; top: -5rem;
background: radial-gradient(circle, rgba(255, 217, 128, 0.5), transparent 65%);
}
.hero::after {
width: 20rem; height: 20rem;
left: -7rem; bottom: -9rem;
background: radial-gradient(circle, rgba(183, 237, 220, 0.6), transparent 60%);
}
.eyebrow {
display: inline-flex;
align-items: center;
gap: 0.5rem;
padding: 0.45rem 0.85rem;
border-radius: 999px;
background: rgba(255, 255, 255, 0.7);
border: 1px solid var(--line);
font-size: 0.85rem;
font-weight: 600;
letter-spacing: 0.02em;
color: var(--muted);
margin-bottom: 1.2rem;
}
.hero-grid {
display: grid;
grid-template-columns: 1.2fr 0.8fr;
gap: 1.5rem;
align-items: start;
}
.lede {
max-width: 60ch;
color: var(--muted);
font-size: 1.05rem;
line-height: 1.7;
margin-bottom: 1.2rem;
}
.badge-row { display: flex; gap: 0.6rem; flex-wrap: wrap; }
.badge {
display: inline-flex;
padding: 0.6rem 0.85rem;
border-radius: 999px;
border: 1px solid var(--line);
background: rgba(255, 255, 255, 0.6);
font-size: 0.85rem;
font-weight: 600;
color: var(--muted);
}
.hero-note {
padding: 1.25rem;
border-radius: var(--radius-lg);
background: linear-gradient(180deg, var(--blue-bg), rgba(29, 90, 232, 0.02));
border: 1px solid rgba(29, 90, 232, 0.12);
}
.hero-note h3 { color: var(--blue); font-size: 0.95rem; letter-spacing: 0.02em; text-transform: uppercase; }
.hero-note p { color: var(--muted); line-height: 1.65; margin-bottom: 0; font-size: 0.95rem; }
/* --- Concept Diagram --- */
.concept-section { text-align: center; }
.concept-section h2 { margin-bottom: 0.5rem; }
.concept-subtitle { color: var(--muted); font-size: 0.95rem; margin-bottom: 1.5rem; }
.concept-svg {
width: 100%;
max-width: 860px;
margin: 0 auto;
display: block;
}
.concept-svg text { font-family: var(--font-body); }
.concept-svg .stage-title { font-weight: 700; font-size: 13px; fill: var(--ink); }
.concept-svg .stage-desc { font-size: 11px; fill: var(--muted); }
.concept-svg .arrow-label { font-size: 10.5px; font-weight: 600; }
.concept-svg .cycle-label { font-size: 10px; fill: var(--subtle); font-style: italic; }
.concept-svg .pod-label { font-size: 9.5px; font-weight: 600; }
@keyframes placeholderPulse {
0%, 100% { opacity: 1; }
50% { opacity: 0.75; }
}
.concept-svg .pulse { animation: placeholderPulse 3s ease-in-out infinite; }
/* --- Legend --- */
.legend {
display: flex;
gap: 1.25rem;
flex-wrap: wrap;
padding: 0.75rem 1.1rem;
border-radius: var(--radius-md);
background: rgba(255, 255, 255, 0.6);
border: 1px solid var(--line);
font-size: 0.85rem;
font-weight: 600;
color: var(--muted);
}
.legend-item {
display: flex;
align-items: center;
gap: 0.45rem;
}
.legend-dot {
width: 14px; height: 14px;
border-radius: 5px;
flex-shrink: 0;
}
.legend-dot.placeholder-dot { background: linear-gradient(180deg, var(--gold-2), var(--gold)); }
.legend-dot.real-dot { background: linear-gradient(180deg, var(--red-2), var(--red)); }
.legend-dot.system-dot { background: linear-gradient(180deg, #d9efeb, #95d6c1); }
.legend-dot.evicted-dot { background: linear-gradient(180deg, #f0f0f0, #ddd); border: 1px dashed #bbb; }
/* --- Step Timeline --- */
.timeline {
display: flex;
align-items: center;
gap: 0;
padding: 0.25rem 0;
}
.timeline-step {
display: flex;
align-items: center;
gap: 0.5rem;
padding: 0.65rem 1rem;
border-radius: 999px;
border: 2px solid var(--line);
background: rgba(255, 255, 255, 0.7);
font-weight: 700;
font-size: 0.88rem;
color: var(--muted);
cursor: pointer;
transition: all 200ms ease;
white-space: nowrap;
position: relative;
}
.timeline-step:hover { border-color: var(--blue); color: var(--ink); transform: translateY(-1px); }
.timeline-step.active {
background: var(--blue);
color: white;
border-color: var(--blue);
box-shadow: 0 4px 16px rgba(29, 90, 232, 0.25);
}
.timeline-step .step-num {
display: inline-flex;
align-items: center;
justify-content: center;
width: 22px; height: 22px;
border-radius: 50%;
background: rgba(0,0,0,0.08);
font-size: 0.78rem;
font-weight: 800;
}
.timeline-step.active .step-num { background: rgba(255,255,255,0.25); }
.timeline-connector {
width: 28px;
height: 2px;
background: var(--line);
flex-shrink: 0;
}
.timeline-connector.passed { background: var(--blue); }
/* --- Tabs --- */
.tab-row { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-bottom: 1rem; }
.tab {
font-family: var(--font-body);
font-weight: 700;
font-size: 0.85rem;
padding: 0.55rem 0.9rem;
border-radius: 999px;
border: 1.5px solid var(--line);
background: rgba(255, 255, 255, 0.7);
color: var(--muted);
cursor: pointer;
transition: all 180ms ease;
}
.tab:hover { border-color: var(--green); color: var(--ink); }
.tab.active {
background: var(--green);
color: white;
border-color: var(--green);
}
/* --- Simulator Grid --- */
.sim-grid {
display: grid;
grid-template-columns: 1.3fr 0.7fr;
gap: 1.25rem;
margin-top: 1rem;
}
/* --- Scene (cluster container) --- */
.scene {
border-radius: var(--radius-xl);
border: 1px solid var(--line);
padding: 1.25rem;
background:
radial-gradient(circle at 20% 10%, rgba(255, 255, 255, 0.85), transparent 16rem),
linear-gradient(180deg, #f7fbff, #fff7ea 65%, #eef8ef);
}
.story {
padding: 1rem 1.15rem;
border-radius: var(--radius-lg);
background: var(--green-bg);
border: 1px solid rgba(27, 140, 111, 0.12);
margin-bottom: 1rem;
line-height: 1.6;
font-size: 0.95rem;
}
.story h3 {
color: var(--green);
font-size: 0.9rem;
text-transform: uppercase;
letter-spacing: 0.03em;
margin-bottom: 0.35rem;
}
.story p { color: var(--muted); margin-bottom: 0; }
/* --- Cluster --- */
.cluster {
display: grid;
grid-template-columns: repeat(4, minmax(0, 1fr));
gap: 0.85rem;
margin-top: 1rem;
}
.node {
border-radius: 18px;
background: linear-gradient(180deg, #fffdf7, var(--node));
border: 2px solid var(--node-edge);
padding: 0.75rem;
min-height: 220px;
box-shadow: inset 0 -8px 0 rgba(231, 194, 105, 0.12);
transition: transform 250ms ease, opacity 250ms ease, box-shadow 250ms ease, border-color 250ms ease;
}
.node h3 { margin-bottom: 0.5rem; font-size: 0.88rem; color: var(--ink); }
.node.offline { opacity: 0.22; transform: scale(0.97); }
.node.highlight {
transform: translateY(-3px);
box-shadow: inset 0 -8px 0 rgba(231, 194, 105, 0.12), 0 14px 32px rgba(34, 44, 50, 0.10);
border-color: var(--gold);
}
.pod-grid {
display: grid;
grid-template-columns: repeat(2, minmax(0, 1fr));
gap: 0.5rem;
}
.pod {
min-height: 64px;
border-radius: 14px;
padding: 0.45rem;
display: grid;
place-items: center;
text-align: center;
border: 1px solid rgba(30, 47, 47, 0.08);
font-weight: 800;
font-size: 0.78rem;
line-height: 1.1;
transition: transform 300ms ease, opacity 300ms ease, background 400ms ease;
}
.pod small {
display: block;
margin-top: 0.2rem;
font-weight: 600;
font-size: 0.65rem;
opacity: 0.8;
}
.pod.placeholder { background: linear-gradient(180deg, var(--gold-2), var(--gold)); }
.pod.real { background: linear-gradient(180deg, var(--red-2), var(--red)); color: #fff9f7; }
.pod.system { background: linear-gradient(180deg, #d9efeb, #95d6c1); }
.pod.evicted {
opacity: 0.16;
transform: scale(0.92);
background: linear-gradient(180deg, #f4f4f4, #e4e4e4);
color: #999;
}
/* --- Metrics --- */
.metrics { display: grid; gap: 0.75rem; margin-top: 1rem; }
.meter-row { display: grid; gap: 0.3rem; }
.meter-head {
display: flex;
justify-content: space-between;
gap: 1rem;
font-size: 0.82rem;
color: var(--muted);
}
.meter-label { font-weight: 700; color: var(--ink); }
.meter-value { font-family: var(--font-mono); font-weight: 500; font-size: 0.8rem; }
.meter {
height: 12px;
border-radius: 999px;
background: rgba(30, 47, 47, 0.06);
overflow: hidden;
}
.fill {
height: 100%;
border-radius: inherit;
width: 0;
transition: width 400ms cubic-bezier(0.4, 0, 0.2, 1);
}
.fill.demand { background: linear-gradient(90deg, var(--red), #ff8a73); }
.fill.spare { background: linear-gradient(90deg, var(--gold), #ffd880); }
.fill.ready { background: linear-gradient(90deg, var(--green), #53c5a2); }
/* --- Explain Panel --- */
.explain-panel h2 { font-size: 1.25rem; margin-bottom: 0.75rem; }
.explain-panel h2:not(:first-of-type) { margin-top: 1.5rem; }
.insight-list, .warning-list { display: grid; gap: 0.6rem; }
.insight {
padding: 0.85rem 1rem;
border-radius: var(--radius-sm);
border: 1px solid var(--line);
background: rgba(255, 255, 255, 0.65);
color: var(--muted);
line-height: 1.6;
font-size: 0.9rem;
display: flex;
gap: 0.6rem;
align-items: flex-start;
}
.insight-icon {
flex-shrink: 0;
width: 22px; height: 22px;
border-radius: 6px;
display: grid;
place-items: center;
font-size: 0.7rem;
font-weight: 800;
background: var(--green-bg);
color: var(--green);
border: 1px solid rgba(27, 140, 111, 0.15);
}
.warning {
padding: 0.85rem 1rem;
border-radius: var(--radius-sm);
border-left: 3px solid var(--gold);
background: var(--gold-bg);
line-height: 1.6;
font-size: 0.9rem;
}
.warning strong { color: var(--ink); font-size: 0.88rem; }
.warning p { color: var(--muted); margin-bottom: 0; margin-top: 0.2rem; font-size: 0.88rem; }
/* --- Fact / Ops / YAML grids --- */
.grid-3 {
display: grid;
grid-template-columns: repeat(3, minmax(0, 1fr));
gap: 1rem;
}
.grid-item {
padding: 1.15rem;
border-radius: var(--radius-lg);
border: 1px solid var(--line);
background: rgba(255, 255, 255, 0.65);
}
.grid-item h3 { display: flex; align-items: center; gap: 0.5rem; }
.grid-item .num {
display: inline-flex;
align-items: center;
justify-content: center;
width: 26px; height: 26px;
border-radius: 8px;
background: var(--blue-bg);
color: var(--blue);
font-size: 0.8rem;
font-weight: 800;
flex-shrink: 0;
}
.grid-item p { color: var(--muted); font-size: 0.9rem; line-height: 1.65; margin-bottom: 0; }
/* --- YAML --- */
.yaml-block {
padding: 1.15rem;
border-radius: var(--radius-lg);
border: 1px solid var(--line);
background: rgba(255, 255, 255, 0.65);
}
.yaml-block h3 { margin-bottom: 0.65rem; }
.yaml-block pre {
margin: 0;
padding: 1rem;
border-radius: var(--radius-md);
background: #0f1f24;
color: #e2f4ee;
overflow-x: auto;
font-family: var(--font-mono);
font-size: 0.82rem;
line-height: 1.5;
tab-size: 2;
}
.yaml-block pre .kw { color: #7ec8e3; }
.yaml-block pre .str { color: #a8d8a8; }
.yaml-block pre .num { color: #f4bd43; }
.yaml-block pre .cmt { color: #667; font-style: italic; }
/* --- Sources --- */
.sources { color: var(--muted); font-size: 0.9rem; line-height: 1.65; }
.sources h2 { font-size: 1.2rem; }
.sources p { margin-bottom: 0.75rem; }
.sources p:last-child { margin-bottom: 0; }
/* --- Keyboard hint --- */
.kbd-hint {
text-align: center;
font-size: 0.78rem;
color: var(--subtle);
margin-top: 0.5rem;
}
.kbd-hint kbd {
display: inline-block;
padding: 0.15rem 0.45rem;
border-radius: 4px;
border: 1px solid var(--line-strong);
background: rgba(255,255,255,0.6);
font-family: var(--font-mono);
font-size: 0.72rem;
}
/* --- Responsive --- */
@media (max-width: 1020px) {
.hero-grid, .sim-grid { grid-template-columns: 1fr; }
.cluster { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-3 { grid-template-columns: 1fr; }
h1 { max-width: none; }
.timeline { flex-wrap: wrap; gap: 0.5rem; }
.timeline-connector { display: none; }
}
@media (max-width: 600px) {
.cluster { grid-template-columns: 1fr 1fr; }
.wrap { padding: 1rem 0 3rem; }
.card { padding: 1.25rem; }
.concept-svg { padding: 0 0.5rem; }
}
</style>
</head>
<body>
<main class="wrap">
<!-- ============================================ -->
<!-- HERO -->
<!-- ============================================ -->
<section class="card hero">
<div class="eyebrow">GKE &middot; Placeholder Pods &middot; Spare Capacity Provisioning</div>
<div class="hero-grid">
<div>
<h1>Le "ballon" GKE, expliqu&eacute; de 5&nbsp;ans &agrave; expert.</h1>
<p class="lede">
Le principe est simple&nbsp;: on fait expr&egrave;s d'occuper un peu de capacit&eacute; avec des Pods jetables
et tr&egrave;s peu prioritaires, pour que le cluster garde des n&oelig;uds d&eacute;j&agrave; pr&ecirc;ts.
Quand un vrai pic arrive, les Pods m&eacute;tiers plus prioritaires prennent cette place
imm&eacute;diatement, sans attendre qu'un nouveau n&oelig;ud d&eacute;marre.
C'est une strat&eacute;gie de <strong>surprovisionnement contr&ocirc;l&eacute;</strong>, pas un gadget.
</p>
<div class="badge-row">
<span class="badge">Version enfant&nbsp;: "des faux passagers gardent les si&egrave;ges"</span>
<span class="badge">Version archi&nbsp;: capacit&eacute; tampon pr&eacute;chauff&eacute;e</span>
<span class="badge">Version ops&nbsp;: priorit&eacute;, pr&eacute;emption, coût</span>
</div>
</div>
<aside class="hero-note">
<h3>R&eacute;sum&eacute; expert</h3>
<p>
Un placeholder Pod d&eacute;clare de vraies <span class="mono">requests</span> CPU/m&eacute;moire,
mais n'ex&eacute;cute qu'un conteneur <span class="mono">pause</span>.
Il force le Cluster Autoscaler &agrave; garder ou cr&eacute;er des n&oelig;uds.
Lorsqu'un Pod de production avec une <span class="mono">PriorityClass</span> sup&eacute;rieure
a besoin de place et que le scheduler ne trouve pas de capacit&eacute; libre,
il pr&eacute;empte les placeholders.
Port&eacute;s par un <span class="mono">Deployment</span>, ils se recr&eacute;ent et
red&eacute;clenchent du spare capacity.
Port&eacute;s par un <span class="mono">Job</span>, ils servent plut&ocirc;t &agrave; un besoin ponctuel.
</p>
</aside>
</div>
</section>
<!-- ============================================ -->
<!-- CONCEPT DIAGRAM (visual summary) -->
<!-- ============================================ -->
<section class="card concept-section">
<h2>Le concept en un coup d'&oelig;il</h2>
<p class="concept-subtitle">Le cycle complet du pattern "balloon", en trois &eacute;tapes.</p>
<svg class="concept-svg" viewBox="0 0 860 290" fill="none" xmlns="http://www.w3.org/2000/svg">
<defs>
<marker id="arr" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto">
<path d="M 0 1 L 9 5 L 0 9 z" fill="#4a6262"/>
</marker>
<linearGradient id="gP" x1="0" y1="0" x2="0" y2="1"><stop offset="0%" stop-color="#ffe3a0"/><stop offset="100%" stop-color="#f4bd43"/></linearGradient>
<linearGradient id="gR" x1="0" y1="0" x2="0" y2="1"><stop offset="0%" stop-color="#ffb2a0"/><stop offset="100%" stop-color="#e1634e"/></linearGradient>
<linearGradient id="gS" x1="0" y1="0" x2="0" y2="1"><stop offset="0%" stop-color="#d9efeb"/><stop offset="100%" stop-color="#95d6c1"/></linearGradient>
<linearGradient id="gE" x1="0" y1="0" x2="0" y2="1"><stop offset="0%" stop-color="#f2f2f2"/><stop offset="100%" stop-color="#ddd"/></linearGradient>
</defs>
<!-- STAGE 1: Reserve -->
<g transform="translate(20, 50)">
<text x="95" y="-14" text-anchor="middle" class="stage-title">1. R&eacute;serve active</text>
<rect x="0" y="0" width="190" height="140" rx="14" fill="#fffdf7" stroke="#e7c269" stroke-width="2" stroke-dasharray="6 4"/>
<!-- Pod grid 2x2 -->
<rect class="pulse" x="10" y="10" width="80" height="54" rx="10" fill="url(#gS)"/>
<text x="50" y="42" text-anchor="middle" class="pod-label" fill="#1e2f2f">System</text>
<rect x="100" y="10" width="80" height="54" rx="10" fill="url(#gR)"/>
<text x="140" y="42" text-anchor="middle" class="pod-label" fill="white">API</text>
<rect class="pulse" x="10" y="74" width="80" height="54" rx="10" fill="url(#gP)"/>
<text x="50" y="106" text-anchor="middle" class="pod-label" fill="#5a4400">Placeholder</text>
<rect class="pulse" x="100" y="74" width="80" height="54" rx="10" fill="url(#gP)"/>
<text x="140" y="106" text-anchor="middle" class="pod-label" fill="#5a4400">Placeholder</text>
<!-- Description -->
<text x="95" y="162" text-anchor="middle" class="stage-desc">Les placeholders r&eacute;servent</text>
<text x="95" y="176" text-anchor="middle" class="stage-desc">de la capacit&eacute; sur le n&oelig;ud</text>
</g>
<!-- ARROW 1 -->
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<text x="263" y="108" text-anchor="middle" class="arrow-label" fill="#e1634e">Pic !</text>
<!-- STAGE 2: Absorption -->
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<text x="95" y="-14" text-anchor="middle" class="stage-title">2. Absorption imm&eacute;diate</text>
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<text x="50" y="42" text-anchor="middle" class="pod-label" fill="#1e2f2f">System</text>
<rect x="100" y="10" width="80" height="54" rx="10" fill="url(#gR)"/>
<text x="140" y="42" text-anchor="middle" class="pod-label" fill="white">API</text>
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<rect x="100" y="74" width="80" height="54" rx="10" fill="url(#gR)"/>
<text x="140" y="106" text-anchor="middle" class="pod-label" fill="white">Queue</text>
<!-- Eviction markers -->
<text x="50" y="90" text-anchor="middle" font-size="8" fill="rgba(255,255,255,0.7)">&#x2190; &eacute;vinc&eacute;</text>
<text x="140" y="90" text-anchor="middle" font-size="8" fill="rgba(255,255,255,0.7)">&#x2190; &eacute;vinc&eacute;</text>
<text x="95" y="162" text-anchor="middle" class="stage-desc">Les vrais workloads</text>
<text x="95" y="176" text-anchor="middle" class="stage-desc">prennent la place (0s d'attente)</text>
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<!-- ARROW 2 -->
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<text x="558" y="108" text-anchor="middle" class="arrow-label" fill="#1b8c6f">Reprise</text>
<!-- STAGE 3: Restoration -->
<g transform="translate(610, 50)">
<text x="115" y="-14" text-anchor="middle" class="stage-title">3. Tampon restaur&eacute;</text>
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<text x="37" y="42" text-anchor="middle" class="pod-label" fill="#1e2f2f">Sys</text>
<rect x="73" y="10" width="55" height="54" rx="8" fill="url(#gR)"/>
<text x="100" y="42" text-anchor="middle" class="pod-label" fill="white">API</text>
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<text x="37" y="106" text-anchor="middle" font-size="8" font-weight="600" fill="#5a4400">Recr&eacute;&eacute;</text>
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<text x="100" y="106" text-anchor="middle" font-size="8" font-weight="600" fill="#5a4400">Recr&eacute;&eacute;</text>
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<rect x="140" y="10" width="80" height="118" rx="10" fill="#fffdf7" stroke="#e7c269" stroke-width="1.5" stroke-dasharray="4 3"/>
<text x="180" y="55" text-anchor="middle" font-size="9" font-weight="600" fill="#e7c269">Nouveau</text>
<text x="180" y="68" text-anchor="middle" font-size="9" font-weight="600" fill="#e7c269">n&oelig;ud</text>
<text x="180" y="100" text-anchor="middle" font-size="20">&#x2795;</text>
<text x="115" y="162" text-anchor="middle" class="stage-desc">Le Deployment recr&eacute;e les placeholders,</text>
<text x="115" y="176" text-anchor="middle" class="stage-desc">l'autoscaler ajoute un n&oelig;ud si n&eacute;cessaire</text>
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<text x="440" y="277" text-anchor="middle" class="cycle-label">Cycle continu (si Deployment)</text>
</svg>
</section>
<!-- ============================================ -->
<!-- INTERACTIVE SIMULATOR -->
<!-- ============================================ -->
<section class="card">
<h2>Simulation interactive</h2>
<!-- Step Timeline -->
<div class="timeline" role="tablist" aria-label="&Eacute;tapes de la simulation">
<button class="timeline-step active" data-step="calme" role="tab" aria-selected="true">
<span class="step-num">1</span> Calme
</button>
<div class="timeline-connector"></div>
<button class="timeline-step" data-step="pic" role="tab" aria-selected="false">
<span class="step-num">2</span> Pic soudain
</button>
<div class="timeline-connector"></div>
<button class="timeline-step" data-step="reconstitution" role="tab" aria-selected="false">
<span class="step-num">3</span> Reconstitution
</button>
<div class="timeline-connector"></div>
<button class="timeline-step" data-step="ponctuel" role="tab" aria-selected="false">
<span class="step-num">4</span> R&eacute;serve ponctuelle
</button>
</div>
<p class="kbd-hint">Naviguez avec <kbd>&larr;</kbd> <kbd>&rarr;</kbd> ou cliquez</p>
<!-- Legend -->
<div class="legend" style="margin-top: 0.75rem;">
<div class="legend-item"><div class="legend-dot placeholder-dot"></div> Placeholder (priorit&eacute; basse, pr&eacute;emptable)</div>
<div class="legend-item"><div class="legend-dot real-dot"></div> Workload r&eacute;el (priorit&eacute; haute)</div>
<div class="legend-item"><div class="legend-dot system-dot"></div> Pod syst&egrave;me (kube-system)</div>
<div class="legend-item"><div class="legend-dot evicted-dot"></div> &Eacute;vinc&eacute; / vide</div>
</div>
<div class="sim-grid">
<!-- LEFT: Cluster + Metrics -->
<div>
<!-- Tabs -->
<div class="tab-row" aria-label="Niveau d'explication" style="margin-top: 1rem;">
<button class="tab active" data-tab="kid">Comme &agrave; 5 ans</button>
<button class="tab" data-tab="tech">Ing&eacute;nieur</button>
<button class="tab" data-tab="ops">Ops / design</button>
</div>
<div class="scene">
<div class="story" id="story"></div>
<div class="metrics">
<div class="meter-row">
<div class="meter-head">
<span class="meter-label">Demande m&eacute;tier</span>
<span class="meter-value" id="demand-label">6 vCPU</span>
</div>
<div class="meter"><div class="fill demand" id="demand-fill"></div></div>
</div>
<div class="meter-row">
<div class="meter-head">
<span class="meter-label">Capacit&eacute; r&eacute;serv&eacute;e (placeholders)</span>
<span class="meter-value" id="spare-label">4 vCPU</span>
</div>
<div class="meter"><div class="fill spare" id="spare-fill"></div></div>
</div>
<div class="meter-row">
<div class="meter-head">
<span class="meter-label">Capacit&eacute; imm&eacute;diatement exploitable</span>
<span class="meter-value" id="ready-label">10 vCPU</span>
</div>
<div class="meter"><div class="fill ready" id="ready-fill"></div></div>
</div>
</div>
<div class="cluster">
<article class="node highlight" id="node-a">
<h3>N&oelig;ud A</h3>
<div class="pod-grid">
<div class="pod system">System<small>DNS / kube-system</small></div>
<div class="pod real" data-slot="a2">API<small>prio haute</small></div>
<div class="pod placeholder" data-slot="a3">Placeholder<small>prio basse</small></div>
<div class="pod placeholder" data-slot="a4">Placeholder<small>prio basse</small></div>
</div>
</article>
<article class="node" id="node-b">
<h3>N&oelig;ud B</h3>
<div class="pod-grid">
<div class="pod system">System<small>observabilit&eacute;</small></div>
<div class="pod real" data-slot="b2">Worker<small>prio haute</small></div>
<div class="pod placeholder" data-slot="b3">Placeholder<small>prio basse</small></div>
<div class="pod placeholder" data-slot="b4">Placeholder<small>prio basse</small></div>
</div>
</article>
<article class="node" id="node-c">
<h3>N&oelig;ud C</h3>
<div class="pod-grid">
<div class="pod placeholder" data-slot="c1">Placeholder<small>prio basse</small></div>
<div class="pod placeholder" data-slot="c2">Placeholder<small>prio basse</small></div>
<div class="pod placeholder" data-slot="c3">Placeholder<small>prio basse</small></div>
<div class="pod placeholder" data-slot="c4">Placeholder<small>prio basse</small></div>
</div>
</article>
<article class="node offline" id="node-d">
<h3>N&oelig;ud D</h3>
<div class="pod-grid">
<div class="pod evicted" data-slot="d1">En attente<small>pas encore cr&eacute;&eacute;</small></div>
<div class="pod evicted" data-slot="d2">En attente<small>pas encore cr&eacute;&eacute;</small></div>
<div class="pod evicted" data-slot="d3">En attente<small>pas encore cr&eacute;&eacute;</small></div>
<div class="pod evicted" data-slot="d4">En attente<small>pas encore cr&eacute;&eacute;</small></div>
</div>
</article>
</div>
</div>
</div>
<!-- RIGHT: Explanation panel -->
<aside class="explain-panel">
<h2>Ce qu'il faut comprendre</h2>
<div class="insight-list" id="explain-panel"></div>
<h2>Pi&egrave;ges classiques</h2>
<div class="warning-list">
<div class="warning">
<strong>Ce n'est pas de la capacit&eacute; gratuite.</strong>
<p>Les placeholders d&eacute;clarent de vraies <span class="mono">requests</span> CPU/m&eacute;moire. Le Cluster Autoscaler dimensionne les n&oelig;uds pour les h&eacute;berger, donc ils influencent directement le co&ucirc;t du cluster.</p>
</div>
<div class="warning">
<strong>Ce n'est pas un remplacement du HPA, VPA ou Cluster Autoscaler.</strong>
<p>C'est une couche tampon compl&eacute;mentaire pour r&eacute;duire le d&eacute;lai d'absorption du premier pic. Les m&eacute;canismes classiques d'autoscaling restent indispensables.</p>
</div>
<div class="warning">
<strong>Le tampon doit &ecirc;tre bien dimensionn&eacute;.</strong>
<p>Trop petit, les pics d&eacute;bordent et vos Pods restent <span class="mono">Pending</span>. Trop grand, vous payez pour du vide durable. Calibrez selon votre burst typique et la dur&eacute;e acceptable de Pending.</p>
</div>
<div class="warning">
<strong>La priorit&eacute; doit &ecirc;tre nette et explicite.</strong>
<p>Les placeholders doivent avoir une <span class="mono">PriorityClass</span> clairement inf&eacute;rieure &agrave; tous les workloads &agrave; prot&eacute;ger. Oubliez une PriorityClass et le scheduler ne pourra pas les pr&eacute;empter.</p>
</div>
</div>
</aside>
</div>
</section>
<!-- ============================================ -->
<!-- DEEP DIVE -->
<!-- ============================================ -->
<section class="card">
<h2>De l'image mentale &agrave; la m&eacute;canique r&eacute;elle</h2>
<div class="grid-3">
<article class="grid-item">
<h3><span class="num">1</span> Ce que c'est</h3>
<p>
Un placeholder Pod est un Pod volontairement "inutile"&nbsp;: il ex&eacute;cute le conteneur
<span class="mono">registry.k8s.io/pause</span> (qui ne fait rien) mais d&eacute;clare de vraies
<span class="mono">requests</span>. Son r&ocirc;le est de mat&eacute;rialiser une r&eacute;serve
de CPU/m&eacute;moire dans le scheduling, for&ccedil;ant l'autoscaling &agrave; maintenir des n&oelig;uds pr&ecirc;ts.
</p>
</article>
<article class="grid-item">
<h3><span class="num">2</span> Pourquoi &ccedil;a existe</h3>
<p>
Sans r&eacute;serve, lors d'un pic soudain, les Pods applicatifs restent
<span class="mono">Pending</span> le temps que le Cluster Autoscaler d&eacute;clenche
la cr&eacute;ation d'un nouveau n&oelig;ud. La documentation GKE indique qu'un n&oelig;ud
prend typiquement <strong>environ 80 &agrave; 120&nbsp;secondes</strong> &agrave; d&eacute;marrer.
Le tampon &eacute;limine cette attente pour le premier burst.
</p>
</article>
<article class="grid-item">
<h3><span class="num">3</span> Comment &ccedil;a marche</h3>
<p>
Les placeholders re&ccedil;oivent une <span class="mono">PriorityClass</span> &agrave; valeur faible
(souvent n&eacute;gative). Lorsqu'un Pod plus prioritaire arrive et que le scheduler
ne trouve pas de capacit&eacute; libre, il pr&eacute;empte les placeholders.
Si un <span class="mono">Deployment</span> les g&egrave;re, le contr&ocirc;leur les recr&eacute;e,
ce qui pousse l'autoscaler &agrave; reconstituer la r&eacute;serve.
</p>
</article>
</div>
</section>
<!-- ============================================ -->
<!-- ARCHITECTURE CHOICES -->
<!-- ============================================ -->
<section class="card">
<h2>Choix d'architecture et d'exploitation</h2>
<div class="grid-3">
<article class="grid-item">
<h3>R&eacute;serve continue</h3>
<p>
Utilisez un <span class="mono">Deployment</span> de placeholders pour un tampon permanent.
Les Pods &eacute;vinc&eacute;s seront recr&eacute;&eacute;s automatiquement par le contr&ocirc;leur,
poussant le cluster &agrave; rester "chaud" en permanence.
C'est le pattern standard pour les services avec des pics impr&eacute;visibles.
</p>
</article>
<article class="grid-item">
<h3>R&eacute;serve ponctuelle</h3>
<p>
Utilisez un <span class="mono">Job</span> pour provisionner de la capacit&eacute; en pr&eacute;vision
d'un &eacute;v&eacute;nement planifi&eacute; (vente flash, campagne marketing).
R&eacute;servez suffisamment t&ocirc;t pour absorber le d&eacute;lai de boot des n&oelig;uds,
puis supprimez le Job apr&egrave;s l'&eacute;v&eacute;nement pour arr&ecirc;ter de payer le surplus.
</p>
</article>
<article class="grid-item">
<h3>Sizing</h3>
<p>
Dimensionnez le tampon selon la formule&nbsp;:
<span class="mono">replicas &times; requests_par_pod</span>.
Param&egrave;tres cl&eacute;s&nbsp;: nombre de Pods &agrave; absorber au burst,
requests par Pod, marge de s&eacute;curit&eacute;, et dur&eacute;e acceptable de
<span class="mono">Pending</span> avant le scale-out complet.
</p>
</article>
</div>
</section>
<!-- ============================================ -->
<!-- YAML EXAMPLES -->
<!-- ============================================ -->
<section class="card">
<h2>Exemple de mise en &oelig;uvre minimale</h2>
<div class="grid-3">
<article class="yaml-block">
<h3>PriorityClass faible</h3>
<pre><span class="kw">apiVersion</span>: scheduling.k8s.io/v1
<span class="kw">kind</span>: PriorityClass
<span class="kw">metadata</span>:
<span class="kw">name</span>: <span class="str">placeholder</span>
<span class="kw">value</span>: <span class="num">-1000</span>
<span class="kw">globalDefault</span>: <span class="num">false</span>
<span class="cmt"># preemptionPolicy: PreemptLowerPriority</span>
<span class="cmt"># (valeur par d&eacute;faut, pas besoin de le sp&eacute;cifier)</span>
<span class="kw">description</span>: <span class="str">"Placeholder pods pour surprovisionnement"</span></pre>
</article>
<article class="yaml-block">
<h3>Deployment continu</h3>
<pre><span class="kw">apiVersion</span>: apps/v1
<span class="kw">kind</span>: Deployment
<span class="kw">metadata</span>:
<span class="kw">name</span>: <span class="str">spare-capacity</span>
<span class="kw">spec</span>:
<span class="kw">replicas</span>: <span class="num">6</span>
<span class="kw">selector</span>:
<span class="kw">matchLabels</span>:
<span class="kw">app</span>: <span class="str">spare-capacity</span>
<span class="kw">template</span>:
<span class="kw">metadata</span>:
<span class="kw">labels</span>:
<span class="kw">app</span>: <span class="str">spare-capacity</span>
<span class="kw">spec</span>:
<span class="kw">priorityClassName</span>: <span class="str">placeholder</span>
<span class="kw">containers</span>:
- <span class="kw">name</span>: <span class="str">pause</span>
<span class="kw">image</span>: <span class="str">registry.k8s.io/pause</span>
<span class="kw">resources</span>:
<span class="kw">requests</span>:
<span class="kw">cpu</span>: <span class="str">"500m"</span>
<span class="kw">memory</span>: <span class="str">"512Mi"</span></pre>
</article>
<article class="yaml-block">
<h3>Lecture op&eacute;rationnelle</h3>
<pre><span class="cmt"># Tampon total = replicas &times; requests</span>
<span class="kw">Exemple avec ce Deployment</span>:
<span class="num">6</span> placeholders &times; <span class="str">500m</span> = <span class="num">3 vCPU</span>
<span class="num">6</span> placeholders &times; <span class="str">512Mi</span> = <span class="num">3 GiB</span>
<span class="cmt"># Cette r&eacute;serve est :</span>
<span class="cmt"># - pr&eacute;emptable par les Pods plus prioritaires</span>
<span class="cmt"># - visible du scheduler (requests, pas limits)</span>
<span class="cmt"># - prise en compte par le Cluster Autoscaler</span>
<span class="cmt"># - payante tant qu'elle existe</span></pre>
</article>
</div>
</section>
<!-- ============================================ -->
<!-- SOURCES -->
<!-- ============================================ -->
<section class="card sources">
<h2>Sources et cadrage</h2>
<p>
V&eacute;rifi&eacute; le 10&nbsp;avril&nbsp;2026 &agrave; partir des documentations officielles&nbsp;:
<a href="https://cloud.google.com/kubernetes-engine/docs/how-to/capacity-provisioning" target="_blank" rel="noreferrer">GKE&nbsp;: Provision extra compute capacity for rapid Pod scaling</a>,
<a href="https://kubernetes.io/docs/tasks/administer-cluster/node-overprovisioning/" target="_blank" rel="noreferrer">Kubernetes&nbsp;: Overprovision Node Capacity For A Cluster</a>,
et la doc GKE sur le bursting
<a href="https://cloud.google.com/kubernetes-engine/docs/how-to/pod-bursting-gke" target="_blank" rel="noreferrer">Configure Pod bursting in GKE</a>.
</p>
<p>
Les points repris ici viennent de ces sources&nbsp;: placeholders &agrave; faible priorit&eacute;,
pr&eacute;emption par des Pods plus prioritaires, usage d'un <span class="mono">Deployment</span>
pour une r&eacute;serve continue, usage d'un <span class="mono">Job</span> pour une r&eacute;serve ponctuelle,
et ordre de grandeur du d&eacute;marrage d'un nouveau n&oelig;ud autour de 80 &agrave; 120&nbsp;secondes.
</p>
<p>
<strong>Note&nbsp;:</strong> GKE propose aussi l'API
<a href="https://cloud.google.com/kubernetes-engine/docs/how-to/provisioningrequest" target="_blank" rel="noreferrer">ProvisioningRequest</a>
(Capacity Provisioning) qui automatise ce pattern de mani&egrave;re native.
Le pattern "balloon" d&eacute;crit ici reste pertinent pour les clusters non-GKE
ou pour un contr&ocirc;le plus fin de la strat&eacute;gie de surprovisionnement.
</p>
</section>
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metrics: { demand: 45, spare: 30, ready: 75, demandLabel: "6 vCPU", spareLabel: "4 vCPU", readyLabel: "10 vCPU" },
story: {
kid: "Le cluster garde des si\u00e8ges occup\u00e9s par des faux voyageurs. Ils ne servent pas \u00e0 travailler, ils servent \u00e0 garder la place chaude pour les vrais passagers qui arriveront d'un coup.",
tech: "Des placeholders avec de vraies requests CPU/m\u00e9moire tournent d\u00e9j\u00e0. Le scheduler voit cette consommation et le Cluster Autoscaler maintient assez de n\u0153uds pour les h\u00e9berger. Aucun workload r\u00e9el n'est impact\u00e9.",
ops: "Vous payez volontairement une r\u00e9serve pr\u00e9emptable. Le b\u00e9n\u00e9fice attendu\u00a0: une meilleure absorption du burst initial, sans attendre un scale-out complet des n\u0153uds (~80-120s)."
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kid: [
"Les placeholders sont des faux passagers qui gardent des si\u00e8ges libres.",
"Quand les vrais passagers arrivent d'un coup, les faux descendent en premier.",
"C'est comme r\u00e9server des places au cin\u00e9ma pour ses amis."
],
tech: [
"Les placeholders mat\u00e9rialisent une capacit\u00e9 tampon via leurs requests (CPU + m\u00e9moire).",
"Le Cluster Autoscaler dimensionne le cluster pour ces Pods aussi\u00a0\u2014\u00a0c'est ce qui cr\u00e9e la r\u00e9serve.",
"Leur priorit\u00e9 faible (PriorityClass n\u00e9gative) pr\u00e9pare leur \u00e9viction future par le scheduler."
],
ops: [
"Le tampon doit couvrir le burst critique, pas toute la charge maximale.",
"Cherchez l'\u00e9quilibre entre la latence d'absorption (souhait\u00e9e\u00a0: ~0s) et le co\u00fbt permanent de la r\u00e9serve.",
"Surveillez les \u00e9victions, les Pods Pending et le d\u00e9lai r\u00e9el de scale-out dans vos m\u00e9triques."
]
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setPod(slots.b3, "placeholder", "Placeholder", "prio basse");
setPod(slots.b4, "placeholder", "Placeholder", "prio basse");
setPod(slots.c1, "placeholder", "Placeholder", "prio basse");
setPod(slots.c2, "placeholder", "Placeholder", "prio basse");
setPod(slots.c3, "placeholder", "Placeholder", "prio basse");
setPod(slots.c4, "placeholder", "Placeholder", "prio basse");
setPod(slots.d1, "evicted", "En attente", "pas encore cr\u00e9\u00e9");
setPod(slots.d2, "evicted", "En attente", "pas encore cr\u00e9\u00e9");
setPod(slots.d3, "evicted", "En attente", "pas encore cr\u00e9\u00e9");
setPod(slots.d4, "evicted", "En attente", "pas encore cr\u00e9\u00e9");
}
},
pic: {
label: "2. Pic soudain",
metrics: { demand: 78, spare: 8, ready: 86, demandLabel: "10,5 vCPU", spareLabel: "1 vCPU", readyLabel: "11,5 vCPU" },
story: {
kid: "D'un coup, plein de vrais passagers arrivent\u00a0! Les faux passagers descendent imm\u00e9diatement, et les vrais s'assoient tout de suite sans attendre un nouveau bus.",
tech: "Des Pods applicatifs plus prioritaires arrivent. Le scheduler ne trouvant pas de capacit\u00e9 libre, il pr\u00e9empte les placeholders. Les ressources qu'ils r\u00e9servaient sont r\u00e9affect\u00e9es instantan\u00e9ment aux workloads m\u00e9tiers.",
ops: "C'est la phase o\u00f9 vous gagnez du temps de r\u00e9ponse. Le cluster absorbe le pic gr\u00e2ce au tampon, pendant que le Cluster Autoscaler et le HPA continuent en arri\u00e8re-plan."
},
explain: {
kid: [
"Les faux passagers perdent leur si\u00e8ge en premier\u00a0\u2014\u00a0c'est fait expr\u00e8s.",
"Les vrais peuvent entrer imm\u00e9diatement sans attendre un nouveau bus.",
"Le service est beaucoup plus rapide quand il y a un rush."
],
tech: [
"La cl\u00e9 n'est pas le Pod placeholder lui-m\u00eame, mais la capacit\u00e9 de n\u0153ud d\u00e9j\u00e0 allou\u00e9e qu'il mat\u00e9rialisait.",
"La pr\u00e9emption est d\u00e9clench\u00e9e par le scheduler quand il ne trouve pas de capacit\u00e9 libre pour un Pod plus prioritaire.",
"Le Pod m\u00e9tier \u00e9vite une attente longue en Pending (~80-120s pour un nouveau n\u0153ud)."
],
ops: [
"Cette strat\u00e9gie r\u00e9duit surtout la latence du premier burst (temps avant que les Pods soient Running).",
"Elle n'annule pas le besoin de scaler ensuite si le pic dure\u00a0\u2014\u00a0HPA + Cluster Autoscaler restent n\u00e9cessaires.",
"V\u00e9rifiez que vos workloads critiques ont bien une PriorityClass sup\u00e9rieure aux placeholders."
]
},
apply() {
nodes.a.className = "node highlight";
nodes.b.className = "node highlight";
nodes.c.className = "node highlight";
nodes.d.className = "node offline";
setPod(slots.a2, "real", "API", "prio haute");
setPod(slots.a3, "real", "API x2", "a pris la place");
setPod(slots.a4, "real", "API x3", "a pris la place");
setPod(slots.b2, "real", "Worker", "prio haute");
setPod(slots.b3, "real", "Worker x2", "a pris la place");
setPod(slots.b4, "real", "Queue", "a pris la place");
setPod(slots.c1, "real", "Checkout", "a pris la place");
setPod(slots.c2, "real", "Checkout x2", "a pris la place");
setPod(slots.c3, "evicted", "\u00c9vinc\u00e9", "lib\u00e8re de la place");
setPod(slots.c4, "evicted", "\u00c9vinc\u00e9", "lib\u00e8re de la place");
setPod(slots.d1, "evicted", "Scale-out", "en cours (~80s)");
setPod(slots.d2, "evicted", "Scale-out", "en cours (~80s)");
setPod(slots.d3, "evicted", "Scale-out", "en cours (~80s)");
setPod(slots.d4, "evicted", "Scale-out", "en cours (~80s)");
}
},
reconstitution: {
label: "3. Reconstitution",
metrics: { demand: 72, spare: 22, ready: 94, demandLabel: "9,5 vCPU", spareLabel: "3 vCPU", readyLabel: "12,5 vCPU" },
story: {
kid: "Les faux passagers reviennent plus tard sur un nouveau bus, pour \u00eatre pr\u00eats pour la prochaine bousculade. On pr\u00e9pare d\u00e9j\u00e0 la suite\u00a0!",
tech: "Comme les placeholders sont g\u00e9r\u00e9s par un Deployment, le contr\u00f4leur tente de les recr\u00e9er. L'autoscaler ajoute un n\u0153ud pour les h\u00e9berger et la r\u00e9serve se reconstitue progressivement.",
ops: "C'est le vrai int\u00e9r\u00eat du pattern continu\u00a0: non seulement absorber le pic, mais restaurer automatiquement le tampon pour le prochain burst. Mesurez le d\u00e9lai de reconstitution."
},
explain: {
kid: [
"Les si\u00e8ges de secours reviennent apr\u00e8s la bousculade.",
"On pr\u00e9pare d\u00e9j\u00e0 le prochain moment charg\u00e9.",
"Le syst\u00e8me redevient pr\u00eat, tout seul."
],
tech: [
"Le Deployment maintient le nombre voulu de replicas (placeholders).",
"Le Cluster Autoscaler voit de nouveau ces Pods \u00e0 placer et provisionne un n\u0153ud.",
"Un nouveau n\u0153ud appara\u00eet (~80-120s) pour recr\u00e9er la r\u00e9serve compl\u00e8te."
],
ops: [
"Mesurez le d\u00e9lai de reconstitution du tampon apr\u00e8s un burst.",
"Dimensionnez ce d\u00e9lai selon votre fr\u00e9quence de pics.",
"Si le burst est continu, la r\u00e9serve peut rester consomm\u00e9e longtemps\u00a0\u2014\u00a0le pattern sert surtout pour les pics ponctuels."
]
},
apply() {
nodes.a.className = "node";
nodes.b.className = "node highlight";
nodes.c.className = "node";
nodes.d.className = "node highlight";
setPod(slots.a2, "real", "API", "prio haute");
setPod(slots.a3, "real", "API x2", "toujours actif");
setPod(slots.a4, "placeholder", "Placeholder", "recr\u00e9\u00e9");
setPod(slots.b2, "real", "Worker", "prio haute");
setPod(slots.b3, "real", "Worker x2", "toujours actif");
setPod(slots.b4, "real", "Queue", "toujours actif");
setPod(slots.c1, "real", "Checkout", "toujours actif");
setPod(slots.c2, "placeholder", "Placeholder", "recr\u00e9\u00e9");
setPod(slots.c3, "placeholder", "Placeholder", "recr\u00e9\u00e9");
setPod(slots.c4, "placeholder", "Placeholder", "recr\u00e9\u00e9");
setPod(slots.d1, "placeholder", "Placeholder", "nouveau n\u0153ud");
setPod(slots.d2, "placeholder", "Placeholder", "nouveau n\u0153ud");
setPod(slots.d3, "placeholder", "Placeholder", "nouveau n\u0153ud");
setPod(slots.d4, "placeholder", "Placeholder", "nouveau n\u0153ud");
}
},
ponctuel: {
label: "4. R\u00e9serve ponctuelle",
metrics: { demand: 54, spare: 0, ready: 54, demandLabel: "7 vCPU", spareLabel: "0 vCPU", readyLabel: "7 vCPU" },
story: {
kid: "Cette fois, on avait pr\u00e9par\u00e9 des si\u00e8ges juste pour une f\u00eate. La f\u00eate est finie, on ne garde plus les faux passagers. On range tout.",
tech: "Un Job de placeholders provisionne de la capacit\u00e9 pour un \u00e9v\u00e9nement ponctuel. Apr\u00e8s usage, le Job se termine et la r\u00e9serve n'est pas reconstitu\u00e9e\u00a0\u2014\u00a0contrairement au pattern Deployment.",
ops: "Bon choix pour un besoin planifi\u00e9 et court (vente flash, campagne). Apr\u00e8s l'\u00e9v\u00e9nement, la capacit\u00e9 redescend et vous arr\u00eatez de payer le surplus. Documentez la proc\u00e9dure d'activation et d'arr\u00eat."
},
explain: {
kid: [
"On pr\u00e9pare des si\u00e8ges seulement quand on sait qu'une foule va venir.",
"Apr\u00e8s la f\u00eate, on range les si\u00e8ges de secours.",
"On \u00e9vite de garder trop de place pour rien."
],
tech: [
"Le Job sert une logique one-shot de provisioning de capacit\u00e9.",
"Il ne maintient pas une r\u00e9serve auto-r\u00e9g\u00e9n\u00e9r\u00e9e apr\u00e8s \u00e9viction.",
"Pattern adapt\u00e9 aux \u00e9v\u00e9nements pr\u00e9visibles o\u00f9 vous connaissez la date du pic."
],
ops: [
"R\u00e9servez t\u00f4t avant l'\u00e9v\u00e9nement pour absorber le d\u00e9lai de boot des n\u0153uds.",
"Supprimez le Job apr\u00e8s l'\u00e9v\u00e9nement pour r\u00e9duire le co\u00fbt.",
"Documentez clairement la proc\u00e9dure d'activation et d'arr\u00eat dans un runbook."
]
},
apply() {
nodes.a.className = "node";
nodes.b.className = "node";
nodes.c.className = "node";
nodes.d.className = "node offline";
setPod(slots.a2, "real", "API", "prio haute");
setPod(slots.a3, "real", "API x2", "apr\u00e8s \u00e9v\u00e9nement");
setPod(slots.a4, "evicted", "Vide", "plus de r\u00e9serve");
setPod(slots.b2, "real", "Worker", "prio haute");
setPod(slots.b3, "real", "Queue", "apr\u00e8s \u00e9v\u00e9nement");
setPod(slots.b4, "evicted", "Vide", "plus de r\u00e9serve");
setPod(slots.c1, "evicted", "Vide", "Job termin\u00e9");
setPod(slots.c2, "evicted", "Vide", "Job termin\u00e9");
setPod(slots.c3, "evicted", "Vide", "Job termin\u00e9");
setPod(slots.c4, "evicted", "Vide", "Job termin\u00e9");
setPod(slots.d1, "evicted", "Arr\u00eat\u00e9", "n\u0153ud retir\u00e9");
setPod(slots.d2, "evicted", "Arr\u00eat\u00e9", "n\u0153ud retir\u00e9");
setPod(slots.d3, "evicted", "Arr\u00eat\u00e9", "n\u0153ud retir\u00e9");
setPod(slots.d4, "evicted", "Arr\u00eat\u00e9", "n\u0153ud retir\u00e9");
}
}
};
/* ============================================
Render
============================================ */
function renderExplanation(stepKey, tabKey) {
const lines = steps[stepKey].explain[tabKey];
explainPanel.innerHTML = lines.map((line, i) =>
`<div class="insight"><div class="insight-icon">${i + 1}</div><span>${line}</span></div>`
).join("");
storyEl.innerHTML = `<h3>${steps[stepKey].label}</h3><p>${steps[stepKey].story[tabKey]}</p>`;
}
function renderMeters(stepKey) {
const m = steps[stepKey].metrics;
demandFill.style.width = `${m.demand}%`;
spareFill.style.width = `${m.spare}%`;
readyFill.style.width = `${m.ready}%`;
demandLabel.textContent = m.demandLabel;
spareLabel.textContent = m.spareLabel;
readyLabel.textContent = m.readyLabel;
}
function updateTimeline() {
const idx = stepOrder.indexOf(currentStep);
timelineSteps.forEach((btn, i) => {
btn.classList.toggle("active", btn.dataset.step === currentStep);
btn.setAttribute("aria-selected", btn.dataset.step === currentStep);
});
connectors.forEach((c, i) => {
c.classList.toggle("passed", i < idx);
});
}
function render() {
updateTimeline();
tabs.forEach(t => t.classList.toggle("active", t.dataset.tab === currentTab));
steps[currentStep].apply();
renderMeters(currentStep);
renderExplanation(currentStep, currentTab);
}
/* ============================================
Events
============================================ */
timelineSteps.forEach(btn => {
btn.addEventListener("click", () => {
currentStep = btn.dataset.step;
render();
});
});
tabs.forEach(tab => {
tab.addEventListener("click", () => {
currentTab = tab.dataset.tab;
render();
});
});
// Keyboard navigation
document.addEventListener("keydown", (e) => {
const idx = stepOrder.indexOf(currentStep);
if (e.key === "ArrowRight" && idx < stepOrder.length - 1) {
currentStep = stepOrder[idx + 1];
render();
e.preventDefault();
} else if (e.key === "ArrowLeft" && idx > 0) {
currentStep = stepOrder[idx - 1];
render();
e.preventDefault();
}
});
/* ============================================
Init
============================================ */
render();
</script>
</body>
</html>
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