{
  "schema": "pg36-ch19-environment-requirements-v1",
  "release": "2.0-sandbox",
  "target": {
    "id": "pg36-l2-vagrant",
    "kind": "disposable-local-linux-sandbox",
    "purpose": "deployment and acceptance rehearsal, never production service",
    "pigsty_version": "v4.4.0",
    "postgresql_major": 18,
    "expected_host_count": 4
  },
  "business_context": {
    "service": "pg36_shop",
    "data_classification": "synthetic teaching data only",
    "business_owner": "pg36_shop service owner placeholder",
    "platform_owner": "database platform team placeholder",
    "production_data_permitted": false,
    "production_traffic_permitted": false
  },
  "service_units": [
    {
      "id": "pg-meta",
      "purpose": "single-node control and validation service",
      "environment": "l2-sandbox",
      "members": [
        {
          "address": "10.10.10.10",
          "declared_role": "primary",
          "offline_query": false
        }
      ],
      "production_slo_claimed": false
    },
    {
      "id": "pg-test",
      "purpose": "three-node HA topology and application-service rehearsal",
      "environment": "l2-sandbox",
      "members": [
        {
          "address": "10.10.10.11",
          "declared_role": "primary",
          "offline_query": false
        },
        {
          "address": "10.10.10.12",
          "declared_role": "replica",
          "offline_query": false
        },
        {
          "address": "10.10.10.13",
          "declared_role": "replica",
          "offline_query": true
        }
      ],
      "production_slo_claimed": false
    }
  ],
  "host_contract": {
    "kernel": "Linux",
    "os_id": "ubuntu",
    "os_version_prefix": "24.04",
    "architecture": "aarch64",
    "uniform_os_and_architecture": true,
    "distinct_machine_identity": true,
    "minimum_cpu_count": 1,
    "minimum_memory_bytes": 1932735283,
    "recommended_minimum_cpu_count": 2,
    "recommended_minimum_memory_bytes": 2147483648,
    "minimum_root_free_bytes": 8589934592,
    "timezone": "Etc/UTC",
    "ntp_synchronized": true,
    "transparent_hugepage_enabled": "never",
    "swap_bytes_max": 0
  },
  "postgresql_initialization_contract": {
    "major": 18,
    "encoding": "UTF8",
    "locale": "C.UTF-8",
    "locale_provider": "builtin",
    "data_checksums": "on",
    "block_size_bytes": 8192,
    "wal_segment_size_bytes": 16777216,
    "timezone": "Etc/UTC",
    "password_encryption": "scram-sha-256",
    "ssl": "on"
  },
  "topology_contract": {
    "pg-meta": {
      "primary": 1,
      "replica": 0,
      "offline": 0
    },
    "pg-test": {
      "primary": 1,
      "replica": 2,
      "offline": 1
    },
    "distinct_postgresql_system_identifiers": true
  },
  "required_active_services": {
    "all_hosts": [
      "haproxy"
    ],
    "postgresql_hosts": [
      "patroni",
      "pgbouncer"
    ],
    "control_host": [
      "etcd",
      "nginx"
    ]
  },
  "hard_rejections": [
    "target identity or host set differs from the declared sandbox",
    "two addresses resolve to the same machine identity",
    "host OS or architecture is heterogeneous",
    "clock is not synchronized or timezone is not UTC",
    "minimum CPU, memory, or free-space floor is missed",
    "PostgreSQL initialization contract differs across members",
    "inventory and live PostgreSQL or Patroni roles disagree",
    "a production SLO is claimed from the sandbox topology",
    "unredacted secret values appear in exported evidence"
  ],
  "accepted_sandbox_exceptions": [
    {
      "id": "EX19-SHARED-HYPERVISOR",
      "reason": "all four VMs share one physical laptop, power source, hypervisor, and storage substrate",
      "production_impact": "node count does not prove independent failure domains"
    },
    {
      "id": "EX19-SINGLE-ETCD",
      "reason": "the teaching sandbox has one etcd member",
      "production_impact": "DCS availability is not production representative"
    },
    {
      "id": "EX19-SINGLE-BACKUP-TARGET",
      "reason": "the teaching sandbox uses one local MinIO/control node",
      "production_impact": "backup repository failure-domain and disaster recovery are not proven"
    },
    {
      "id": "EX19-VIRTUAL-STORAGE",
      "reason": "Vagrant virtual disks have no production IOPS, latency, endurance, or redundancy qualification",
      "production_impact": "capacity and durability conclusions are prohibited"
    },
    {
      "id": "EX19-INVENTORY-SECRETS",
      "reason": "randomized sandbox secrets are stored in a mode-0600 temporary inventory",
      "production_impact": "a production secret authority, rotation, and audit path remain required"
    },
    {
      "id": "EX19-LAB-RESOURCE-FLOOR",
      "reason": "the three pg-test VMs have one vCPU and about 1.9 GiB RAM, below the chapter recommendation of two vCPUs and 2 GiB",
      "production_impact": "the successful deployment proves only the disposable sandbox acceptance floor; it cannot justify production sizing or concurrency claims"
    }
  ],
  "gate_interpretation": {
    "sandbox_l2": "may pass with the six named exceptions",
    "ch19_deployment_baseline": "remains pending for a real pg-ha-standard production target",
    "next_gate": "ch20-ha"
  }
}