Deliverables

flowchart TB
  root["Organisation Root<br/><i>policy: deny unapproved regions</i>"]

  subgraph plat["Platform"]
    direction TB
    ident["Identity<br/><i>directory, privileged access</i>"]
    conn["Connectivity<br/><i>hub VNet/VPC, firewall, DNS, VPN</i>"]
    mgmt["Management<br/><i>logs, backup, monitoring</i>"]
  end

  subgraph land["Landing Zones"]
    direction TB
    subgraph corp["Corporate"]
      p1["Prod A<br/><i>spoke</i>"]
      n1["Non-Prod A<br/><i>spoke</i>"]
    end
    subgraph online["Internet-Facing"]
      p2["Prod B<br/><i>spoke</i>"]
      n2["Non-Prod B<br/><i>spoke</i>"]
    end
  end

  sandbox["Sandbox<br/><i>spend cap, no connectivity, auto-expire</i>"]
  decom["Decommissioned<br/><i>deny all</i>"]

  root --> plat
  root --> land
  root --> sandbox
  root --> decom
  conn --- p1
  conn --- n1
  conn --- p2
  conn --- n2
  mgmt -.->|"diagnostics forwarded"| land
  ident -.->|"roles and groups"| land

flowchart TB
  users(["Users"]) --> dns["Global DNS<br/><i>latency routing + health checks</i>"]

  subgraph r1["Region: primary"]
    direction TB
    lb1["Load Balancer<br/><i>public</i>"]
    subgraph az1["Zone A"]
      n1["Node Pool<br/><i>api ×3, worker ×2</i>"]
    end
    subgraph az2["Zone B"]
      n2["Node Pool<br/><i>api ×3, worker ×2</i>"]
    end
    subgraph az3["Zone C"]
      n3["Node Pool<br/><i>api ×2, worker ×1</i>"]
    end
    db1[("Primary DB<br/><i>synchronous replica in Zone B</i>")]
    lb1 --> n1
    lb1 --> n2
    lb1 --> n3
    n1 --> db1
    n2 --> db1
    n3 --> db1
  end

  subgraph r2["Region: secondary"]
    direction TB
    lb2["Load Balancer<br/><i>warm</i>"]
    n4["Node Pool<br/><i>api ×2, scaled down</i>"]
    db2[("Read Replica<br/><i>asynchronous — RPO 30s</i>")]
    lb2 --> n4 --> db2
  end

  dns --> lb1
  dns -.->|"failover only"| lb2
  db1 -.->|"async replication"| db2

flowchart TB
  subgraph pri["Primary site"]
    direction TB
    p1["Application tier"]
    p2[("Transactional DB")]
    p3[("Object storage")]
    p4["Secrets + config"]
  end
  subgraph dr["Recovery site — warm"]
    direction TB
    d1["Application tier<br/><i>scaled to 0 · IaC ready</i>"]
    d2[("DB replica<br/><i>async · lag &lt; 30s</i>")]
    d3[("Storage replica<br/><i>cross-region · 15 min</i>")]
    d4["Secrets replicated"]
  end

  p2 ==>|"async"| d2
  p3 ==>|"async"| d3
  p4 ==>|"sync"| d4

  subgraph run["Recovery sequence — tested 2026-05-18"]
    direction TB
    s1["1. Declare · 5 min"]
    s2["2. Promote replica · 8 min"]
    s3["3. Scale app tier · 6 min"]
    s4["4. Repoint DNS · 5 min<br/><i>TTL 60s</i>"]
    s5["5. Verify + reconcile · 12 min"]
    s1 --> s2 --> s3 --> s4 --> s5
  end
  dr --> run
  run --> res(["Restored — measured RTO 36 min"])

flowchart LR
  subgraph e1["Ephemeral / PR"]
    direction TB
    a1["scaled to 1<br/>mocked externals<br/>synthetic data<br/><i>proves: it builds and unit-passes</i><br/>auto-destroy 24h"]
  end
  subgraph e2["Dev"]
    direction TB
    a2["shared<br/>real internal deps<br/>synthetic data<br/><i>proves: integration wiring</i><br/>anyone deploys"]
  end
  subgraph e3["Staging"]
    direction TB
    a3["prod-shaped topology<br/>real deps · sandbox externals<br/>masked prod-like data<br/><i>proves: contracts + performance</i><br/>pipeline only"]
  end
  subgraph e4["Production"]
    direction TB
    a4["full scale · multi-AZ<br/>real data<br/><i>proves: nothing — it serves</i><br/>pipeline + gate"]
  end
  e1 --> e2 --> e3 --> e4
  note["Same artifact promoted throughout.<br/>Config differs; the image digest does not."]

flowchart TB
  subgraph prod["Cluster: prod-eu (regional, 3 AZ)"]
    direction TB
    cp["Control plane<br/><i>managed · private endpoint</i>"]
    subgraph pools["Node pools"]
      direction LR
      np1["system<br/><i>taint: CriticalAddonsOnly</i>"]
      np2["general<br/><i>3–30 nodes · spot 40%</i>"]
      np3["memory<br/><i>taint: workload=memory</i>"]
      np4["gpu<br/><i>taint: workload=gpu</i>"]
    end
    subgraph ns["Namespaces"]
      direction LR
      n1["team-orders<br/><i>quota · NetworkPolicy<br/>default-deny</i>"]
      n2["team-pricing<br/><i>quota · NetworkPolicy</i>"]
      n3["platform<br/><i>mesh · ingress · logging</i>"]
    end
    cp --- pools
    pools --- ns
  end
  subgraph nonprod["Cluster: nonprod-eu"]
    direction TB
    x1["shared node pool<br/><i>spot 90%</i>"]
  end
  reg[("Image registry<br/><i>signed images only</i>")] --> prod
  reg --> nonprod
  gitops["GitOps reconciler"] -.->|"applies desired state"| prod

flowchart TB
  u(["Users"]) --> gslb["Global traffic manager<br/><i>health + latency routing</i>"]

  subgraph ra["Region A — write primary"]
    direction TB
    a1["Edge + API"]
    a2["Services"]
    a3[("Primary DB<br/><i>accepts writes</i>")]
    a1 --> a2 --> a3
  end

  subgraph rb["Region B — read + standby"]
    direction TB
    b1["Edge + API"]
    b2["Services"]
    b3[("Replica<br/><i>read only · lag &lt; 2s</i>")]
    b1 --> b2 --> b3
  end

  gslb -->|"reads: nearest"| a1
  gslb -->|"reads: nearest"| b1
  gslb -->|"writes: always A"| a1
  b2 -.->|"write forwarding<br/>+45ms"| a2
  a3 ==>|"async replication"| b3
  arb{{"Failover arbitration<br/><i>manual promote · documented<br/>RPO &le; 2s · RTO 15 min</i>"}}
  arb -.-> a3
  arb -.-> b3

flowchart TB
  inet(["Internet"])
  dc["Corporate Data Centre<br/><i>10.0.0.0/8</i>"]

  subgraph hub["Hub — 10.100.0.0/16"]
    direction TB
    fw["Egress Firewall<br/><i>FQDN allow-list</i>"]
    vpn["VPN / Direct Link<br/><i>BGP</i>"]
    dns["Private DNS Resolver"]
  end

  subgraph spokeA["Spoke: Prod — 10.101.0.0/16"]
    direction TB
    pub["Public Subnet<br/><i>10.101.0.0/24 — ingress LB only</i>"]
    app["App Subnet<br/><i>10.101.10.0/23 — no public IPs</i>"]
    data["Data Subnet<br/><i>10.101.20.0/24 — private endpoints</i>"]
    pub --> app --> data
  end

  subgraph spokeB["Spoke: Non-Prod — 10.102.0.0/16"]
    appn["App Subnet<br/><i>10.102.10.0/23</i>"]
  end

  inet -->|"443 only"| pub
  app -->|"all egress"| fw --> inet
  appn --> fw
  dc <-->|"BGP"| vpn
  vpn --- spokeA
  vpn --- spokeB
  spokeA x--x spokeB