# Configuration Reference

This is the live configuration reference for the OtOpcUa Host (`src/Server/ZB.MOM.WW.OtOpcUa.Host/`). It enumerates the `appsettings*.json` sections, the bound Options classes, and the `OTOPCUA_*` / sim-endpoint environment variables — every entry grounded in source.

Two related concerns get their own dedicated pages and are **only summarised + linked** here, not duplicated:

- **Transport security, OPC UA authentication, LDAP, data-/control-plane authorization** → [`security.md`](security.md)
- **Redundancy + the `Cluster` section** → [`Redundancy.md`](Redundancy.md)

## How configuration is layered

The Host (`Program.cs`) loads `appsettings.json`, then overlays a **per-role** file chosen from the cluster roles:

- A single role → `appsettings.{role}.json` (e.g. `appsettings.driver.json`, `appsettings.admin.json`).
- Both roles → `appsettings.admin-driver.json` (roles joined with `-`, ordinal-sorted).
- `appsettings.{ASPNETCORE_ENVIRONMENT}.json` (e.g. `appsettings.Development.json`) is layered on by the host builder.

All role overlays are **optional** — the base `appsettings.json` plus the Options-class C# defaults are enough to boot. The roles themselves come from the `OTOPCUA_ROLES` env var (see [`ServiceHosting.md`](ServiceHosting.md) and the table below).

The checked-in `appsettings*.json` files are deliberately thin: they carry only `Serilog` and the `Security:Ldap` overlay. Everything else (`OpcUa`, `Cluster`, `ConnectionStrings`/`ConfigDb`) binds from the Options-class defaults documented below unless an operator adds the section explicitly or supplies the corresponding environment variable.

---

## `appsettings` sections

### `Serilog`

- **Purpose:** logging. Console + rolling daily file sink, layered with the shared `ZB.MOM.WW.Telemetry` enrichers (`AddZbSerilog` in `Program.cs`).
- **Where bound:** `builder.AddZbSerilog(...)` reads `Serilog` from configuration (`ReadFrom.Configuration`).
- **Checked-in shape** (`appsettings.json`): `Using` = `[ "Serilog.Sinks.Console", "Serilog.Sinks.File" ]`, `WriteTo` = a `Console` sink and a `File` sink (`path: logs/otopcua-.log`, `rollingInterval: Day`). Role overlays add `MinimumLevel` / `Override` blocks (e.g. `Opc.Ua: Debug`, `Akka: Information`).

### `OpcUa`

- **Purpose:** the OPC UA server endpoint identity, listening port, PKI, transport-security profiles, and redundancy peer advertising.
- **Options class:** `OpcUaApplicationHostOptions` — `src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OpcUaApplicationHost.cs`.
- **Bound by:** `AddValidatedOptions<OpcUaApplicationHostOptions, OpcUaApplicationHostOptionsValidator>(config, "OpcUa")` in `Program.cs` (driver-role only). Validated fail-fast at startup by `OpcUaApplicationHostOptionsValidator` (`src/Server/ZB.MOM.WW.OtOpcUa.Host/Configuration/OpcUaApplicationHostOptionsValidator.cs`).

| Key | Type | Default | Meaning |
|---|---|---|---|
| `ApplicationName` | string | `OtOpcUa` | Server application name. Required (validated). |
| `ApplicationUri` | string | `urn:OtOpcUa` | Server application URI. Must be unique per redundancy node. Required. |
| `ProductUri` | string | `https://zb.com/otopcua` | Product URI. Not validated. |
| `OpcUaPort` | int | `4840` | Binary endpoint listen port. Validated as a port. |
| `PublicHostname` | string | `0.0.0.0` | Hostname/IP advertised in endpoint descriptions. Required. |
| `ApplicationConfigPath` | string? | `null` | Optional path to an application config XML; loaded instead of building from defaults. |
| `PkiStoreRoot` | string | `pki` | Root of the PKI hierarchy (`own`/`issuer`/`trusted`/`rejected` substores created under it). Required. See [`security.md`](security.md). |
| `EnabledSecurityProfiles` | list of `OpcUaSecurityProfile` | `[None, Basic256Sha256Sign, Basic256Sha256SignAndEncrypt]` | Transport-security profiles, one endpoint per entry. Must contain ≥1. Profile detail in [`security.md`](security.md). |
| `AutoAcceptUntrustedClientCertificates` | bool | `false` | Auto-trust unknown client certs on first connect (dev convenience). Not validated. See [`security.md`](security.md). |
| `PeerApplicationUris` | list of string | `[]` (empty) | Partner node `ApplicationUri`s published in `Server.ServerArray` for redundancy discovery. See [`Redundancy.md`](Redundancy.md). |

> **Transport security profiles** (the values in `EnabledSecurityProfiles` — `None`, `Basic256Sha256Sign`, `Basic256Sha256SignAndEncrypt`) and the PKI trust flow are documented in full in [`security.md`](security.md). This page does not duplicate them.

### `Security`

- **Purpose:** Admin-UI and OPC UA authentication. Three subsections, each its own Options class:

| Subsection | Options class (`SectionName`) | Purpose |
|---|---|---|
| `Security:Ldap` | `LdapOptions` — `src/Server/ZB.MOM.WW.OtOpcUa.Security/Ldap/LdapOptions.cs` | LDAP bind for Admin cookie login + OPC UA UserName tokens. Bound by `AddValidatedOptions<LdapOptions, LdapOptionsValidator>` in `Program.cs`. |
| `Security:Jwt` | `JwtOptions` — `src/Server/ZB.MOM.WW.OtOpcUa.Security/Jwt/JwtOptions.cs` | Signing config for the JWT minted at `/auth/token` for **external** consumers (OPC UA clients / automation). |
| `Security:Cookie` | `OtOpcUaCookieOptions` — `src/Server/ZB.MOM.WW.OtOpcUa.Security/CookieOptions.cs` | The Admin-UI auth cookie (`AddOtOpcUaAuth` copies these onto `CookieAuthenticationOptions`). |

**`Security:Ldap` — see [`security.md`](security.md) for the full field-by-field reference and bind-flow.** The checked-in role overlays set only `DevStubMode` and `Transport`; the remaining `LdapOptions` fields (`Enabled`, `Server`, `Port`, `AllowInsecure`, `SearchBase`, `ServiceAccountDn`, `ServiceAccountPassword`, `GroupAttribute`, `DisplayNameAttribute`, `UserNameAttribute`, `GroupToRole`) are covered there.

**`Security:Jwt`** key fields (`JwtOptions`):

| Key | Type | Default | Meaning |
|---|---|---|---|
| `SigningKey` | string | `""` | HS256 signing key; must be ≥32 bytes UTF-8. Set from your secret store — never commit a value. |
| `Issuer` | string | `otopcua` | JWT issuer. |
| `Audience` | string | `otopcua` | JWT audience. |
| `ExpiryMinutes` | int | `15` | Token lifetime. |

**`Security:Cookie`** key fields (`OtOpcUaCookieOptions`):

| Key | Type | Default | Meaning |
|---|---|---|---|
| `Name` | string | `ZB.MOM.WW.OtOpcUa.Auth` | Auth cookie name. Changing it invalidates existing sessions on next deploy. |
| `ExpiryMinutes` | int | `30` | Idle sliding-window length. |
| `RequireHttpsCookie` | bool | `true` | `SecurePolicy = Always`. Set `false` only for plain-HTTP local dev (emits a startup Warning). |

> Authentication, data-plane authorization (`NodeAcl` / `PermissionTrie`), and control-plane Admin roles are all in [`security.md`](security.md).

### `Cluster`

- **Purpose:** Akka.NET cluster identity, transport, and roles — the backbone of redundancy.
- **Options class:** `AkkaClusterOptions` (`SectionName = "Cluster"`) — `src/Core/ZB.MOM.WW.OtOpcUa.Cluster/AkkaClusterOptions.cs`. Bound by `AddOtOpcUaCluster(config)` in `Program.cs`.

| Key | Type | Default | Meaning |
|---|---|---|---|
| `SystemName` | string | `otopcua` | Akka actor-system name. |
| `Hostname` | string | `0.0.0.0` | Bind hostname. |
| `Port` | int | `4053` | Cluster transport port. |
| `PublicHostname` | string | `127.0.0.1` | Hostname advertised in cluster gossip; must be reachable by peers. |
| `SeedNodes` | string[] | `[]` | Seed nodes for bootstrapping. |
| `Roles` | string[] | `[]` | Cluster roles for this node. When empty, falls back to `OTOPCUA_ROLES`. Allowed values: `admin`, `driver`, `dev`. |

> The full redundancy model (ServiceLevel tiers, split-brain, peer discovery) is in [`Redundancy.md`](Redundancy.md). The OPC UA peer-URI advertising lives in the `OpcUa:PeerApplicationUris` key above.

### `ConnectionStrings` → `ConfigDb`

- **Purpose:** the central Config DB connection string. **Required for every role** — `Program.cs` calls `AddOtOpcUaConfigDb` unconditionally.
- **Bound by:** `AddOtOpcUaConfigDb(config)` (`src/Core/ZB.MOM.WW.OtOpcUa.Configuration/ServiceCollectionExtensions.cs`). The connection-string name constant is `ConnectionStringName = "ConfigDb"`, read via `configuration.GetConnectionString("ConfigDb")`. If absent, startup throws with a message pointing to either `appsettings.json` or the `OTOPCUA_CONFIG_CONNECTION` env var.
- **Shape:** standard `ConnectionStrings:ConfigDb` SQL Server connection string. There is no checked-in default in the thin `appsettings*.json` — supply it per environment.

The Config DB itself (the EF Core `OtOpcUaConfigDbContext`, entities, draft/publish generations, `NodeAcl`, `LdapGroupRoleMapping`, migrations) is the durable home for the fleet's drivers, UNS hierarchy, ACLs, and audit log. For the **full schema** see [`docs/v2/config-db-schema.md`](v2/config-db-schema.md). This page does not duplicate it.

### Galaxy / MxAccess driver config (`DriverConfig` JSON, not `appsettings`)

The Galaxy/MxAccess connection settings are **not an `appsettings` section.** They are driver-instance options stored in the `DriverConfig` JSON column of the Config DB (edited via the Admin UI), bound to `GalaxyDriverOptions` (`src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Contracts/GalaxyDriverOptions.cs`, namespace `...Driver.Galaxy.Config`). It decomposes into nested records:

| Record | Key fields (default) | Meaning |
|---|---|---|
| `GalaxyGatewayOptions` (`Gateway`) | `Endpoint`; `ApiKeySecretRef`; `UseTls` (`true`); `CaCertificatePath` (`null`); `ConnectTimeoutSeconds` (`10`); `DefaultCallTimeoutSeconds` (`30`); `StreamTimeoutSeconds` (`0` = unlimited) | mxaccessgw gateway connection. `ApiKeySecretRef` supports `env:NAME` / `file:PATH` / `dev:KEY` / literal forms (resolved at `InitializeAsync`); prefer `env:`/`file:` in production. Never store a cleartext key. |
| `GalaxyMxAccessOptions` (`MxAccess`) | `ClientName`; `PublishingIntervalMs` (`1000`); `WriteUserId` (`0` = anonymous); `EventPumpChannelCapacity` (`50000`) | MXAccess client identity + tuning. `ClientName` **must be unique per OtOpcUa instance** (redundancy pairs enforce this). |
| `GalaxyRepositoryOptions` (`Repository`) | `DiscoverPageSize` (`5000`); `WatchDeployEvents` (`true`) | Galaxy Repository browse paging + deploy-event watching. |
| `GalaxyReconnectOptions` (`Reconnect`) | `InitialBackoffMs` (`500`); `MaxBackoffMs` (`30000`); `ReplayOnSessionLost` (`true`) | In-driver reconnect-supervisor backoff. |
| (top-level) | `ProbeTimeoutSeconds` (`30`, range 1–60) | AdminUI Test-Connect probe timeout. |

> The `OTOPCUA_GALAXY_*` environment variables that v1's in-process `Galaxy.Host` consumed **no longer live in this repo** — they moved into the separately-installed mxaccessgw gateway's own config (see the v1 archive pointer in `docs/README.md` and the Galaxy overview at [`docs/drivers/Galaxy.md`](drivers/Galaxy.md)). The only Galaxy connection secret this repo touches is the gateway API key via `ApiKeySecretRef` above.

### Historian config (env-driven sidecar)

The Wonderware Historian runs as a supervised sidecar process whose configuration arrives **entirely through environment variables**, not an `appsettings` section. The sidecar entry point (`src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware/Program.cs`) reads them at spawn time. See the `OTOPCUA_HISTORIAN_*` rows in the environment-variable table below. The in-process client-side options POCO is `WonderwareHistorianClientOptions` (`src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware.Client.Contracts/WonderwareHistorianClientOptions.cs`): `PipeName`, `SharedSecret`, `PeerName` (`OtOpcUa`), `ConnectTimeout` (default 10s), `CallTimeout` (default 30s), `ProbeTimeoutSeconds` (`15`).

---

## Environment variables

All names are read in this repo's source via `Environment.GetEnvironmentVariable(...)` unless noted otherwise. Defaults shown are the in-source fallbacks.

### Host / cluster / Config DB

| Variable | Read by | Effect / default |
|---|---|---|
| `OTOPCUA_ROLES` | `src/Server/ZB.MOM.WW.OtOpcUa.Host/Program.cs` (`RoleParser.Parse`) | Comma-separated cluster roles for the node (`admin`, `driver`, `dev`). Drives the conditional wiring and the per-role appsettings overlay. Used when `Cluster:Roles` is empty. |
| `OTOPCUA_CONFIG_CONNECTION` | `src/Core/ZB.MOM.WW.OtOpcUa.Configuration/DesignTimeDbContextFactory.cs` (design-time / `dotnet ef` only) | Read at **design time** by `DesignTimeDbContextFactory.cs` for `dotnet ef` migrations. At **runtime** the server resolves the connection string from `ConnectionStrings:ConfigDb` (env form: `ConnectionStrings__ConfigDb`) via `configuration.GetConnectionString("ConfigDb")` in `ServiceCollectionExtensions.cs` — `OTOPCUA_CONFIG_CONNECTION` appears there only as a hint in an error message, not via `GetEnvironmentVariable`. No credential is embedded in source. |
| `OTOPCUA_ALLOWED_SID` | `src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware/Program.cs` | SID of the server principal allowed to connect to the historian sidecar's named pipe (passed by the supervisor at spawn). Required — sidecar throws if unset. |
| `ASPNETCORE_ENVIRONMENT` | ASP.NET host builder (framework) | Selects `appsettings.{Environment}.json` (e.g. `Development`). |

### Historian sidecar (`OTOPCUA_HISTORIAN_*`)

All read in `src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Historian.Wonderware/Program.cs`.

| Variable | Effect / default |
|---|---|
| `OTOPCUA_HISTORIAN_PIPE` | Named-pipe name the sidecar listens on. Required (throws if unset). |
| `OTOPCUA_HISTORIAN_SECRET` | Per-process shared secret verified in the pipe Hello frame. Required (throws if unset). |
| `OTOPCUA_HISTORIAN_ENABLED` | `true` opens the real Wonderware SDK connection; anything else → pipe-only mode (smoke/IPC tests). Default: not-true → pipe-only. |
| `OTOPCUA_HISTORIAN_ALARM_WRITE_ENABLED` | `false` disables the alarm-event writer (sidecar rejects `WriteAlarmEvents`). Default `true` (when `ENABLED=true`). |
| `OTOPCUA_HISTORIAN_INTEGRATED` | `false` → SQL auth (use `USER`/`PASS`); any other value → integrated security. Default: integrated. |
| `OTOPCUA_HISTORIAN_SERVER` | Historian server hostname. Default `localhost`. |
| `OTOPCUA_HISTORIAN_SERVERS` | Comma-separated multi-node server list (overrides single `SERVER` when set). |
| `OTOPCUA_HISTORIAN_PORT` | Historian port. Default `32568`. |
| `OTOPCUA_HISTORIAN_USER` | SQL username (when not integrated). |
| `OTOPCUA_HISTORIAN_PASS` | SQL password (when not integrated). Never commit a value. |
| `OTOPCUA_HISTORIAN_TIMEOUT_SEC` | Command timeout (seconds). Default `30`. |
| `OTOPCUA_HISTORIAN_MAX_VALUES` | Max values returned per read. Default `10000`. |
| `OTOPCUA_HISTORIAN_COOLDOWN_SEC` | Failure cooldown (seconds). Default `60`. |

### Driver integration-test / fixture sim endpoints

These are consumed by the driver **integration-test fixtures** (under `tests/Drivers/...IntegrationTests/`), not by the production server. Each overrides the simulator endpoint a fixture TCP-probes; defaults point at the shared Docker host `10.100.0.35` (see `CLAUDE.md` Docker Workflow).

| Variable | Read by (fixture) | Default |
|---|---|---|
| `MODBUS_SIM_ENDPOINT` | `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Modbus.IntegrationTests/ModbusSimulatorFixture.cs` | `10.100.0.35:5020` |
| `AB_SERVER_ENDPOINT` | `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip.IntegrationTests/AbServerFixture.cs` | `10.100.0.35:44818` |
| `S7_SIM_ENDPOINT` | `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7.IntegrationTests/Snap7ServerFixture.cs` | `10.100.0.35:1102` (non-privileged; not S7-standard 102) |
| `OPCUA_SIM_ENDPOINT` | `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests/OpcPlcFixture.cs` | `opc.tcp://10.100.0.35:50000` |
| `OTOPCUA_FOCAS_SIM_ENDPOINT` | `tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.IntegrationTests/FocasSimFixture.cs` | `localhost:8193` |

> Additional harness/parity/soak env vars (`OTOPCUA_FOCAS_*`, `OTOPCUA_PARITY_*`, `OTOPCUA_SOAK_*`, `OTOPCUA_HARNESS_USE_SQL`) exist only in the test/parity/soak harnesses, not in production source, and are out of scope for this reference.

---

## See also

- [`security.md`](security.md) — transport security, OPC UA authentication, LDAP (`Security:Ldap`), data-plane ACLs, control-plane roles.
- [`Redundancy.md`](Redundancy.md) — the `Cluster` section in the context of warm/hot redundancy, ServiceLevel, peer discovery.
- [`ServiceHosting.md`](ServiceHosting.md) — role-based host wiring and `OTOPCUA_ROLES`.
- [`docs/drivers/Galaxy.md`](drivers/Galaxy.md) — Galaxy/MxAccess driver overview.
- [`docs/v2/config-db-schema.md`](v2/config-db-schema.md) — the full Config DB schema.