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Klaus LandsdorfandMarc Schier
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# Description Follow-up to the AutoID companion (#4825). Two changes to where the AutoID server places its readers: 1. **`IAutoIdReaderBuilder.WithParent` is made conformant with OPC 10000-100 4.9.** Until now it placed a reader below another node *instead of* `DeviceSet`, and the docs suggested "a component of a machine" as the use case. A machine in the Machinery `Machines` folder is not reachable from `DeviceSet`, so such a reader could not be located from `DeviceSet`, which DI 4.9 requires for every `ComponentType` instance (every AutoID device type derives from DI `DeviceType`). Now the reader is still placed below the parent (`HasComponent`, unchanged), and: - when `DeviceSet` already reaches the parent through hierarchical references (for example another reader, or any device it organizes), nothing else is added: the reader is a component of a composed device and DI 4.9 wants "only the root instance" referenced from `DeviceSet`; - otherwise `DeviceSet` also organizes the reader (`Organizes`, both directions), so it stays locatable. 2. **New opt-in `IAutoIdReaderBuilder.AsComponentOf(BaseObjectState machine)`**, available only when AutoID is composed with Machinery (`AddAutoIdToMachinery`, or a DI owner that loads the Machinery model). It makes the reader an identifiable component of the machine per OPC 40001-1 11: - the reader is placed below the machine's `Components` add-in (`HasComponent`, as `MachineComponentsType` declares for `<Component>`); - it gets the `2:Identification` add-in (`HasAddIn`) typed `MachineryComponentIdentificationType`, which holds no copies: it references the reader's own DI nameplate properties with `HasProperty` (`Manufacturer`, `SerialNumber`, and those of `Model`, `ManufacturerUri`, `ProductCode`, `HardwareRevision`, `SoftwareRevision`, `DeviceRevision`, `DeviceClass`, `ProductInstanceUri` that are set, plus `AssetId`/`ComponentName` when published; `DeviceManual` and `RevisionCounter` are left out as 40001-1 10.2 recommends); - the reader stays a device: the same `DeviceSet` rule as for `WithParent` applies with `Components` as the parent, so in the usual case (a machine in `Machines` that `DeviceSet` does not reach) `DeviceSet` organizes it directly. It is not added to `Machines`. - Checked before anything is registered, each failing with `Bad_ConfigurationError` and a message naming the way out: the server has no Machinery model (names `AddAutoIdToMachinery`), the machine is not a node of the AutoID owner, the machine has no `Components` add-in (names `WithComponents`), or the reader nameplate lacks `Manufacturer` and/or `SerialNumber` (mandatory in `MachineryItemIdentificationType`). `WithParent` and `AsComponentOf` exclude each other (`InvalidOperationException`). Default behaviour is unchanged: a reader built without `WithParent`/`AsComponentOf` is organized by `DeviceSet` and not added to `Machines`. Rollback on failure covers the new references: a failed build removes the `DeviceSet` reference, the component and its add-in, so the name can be used again. ## Specification basis | Statement | Source | | --- | --- | | "The DeviceSet Object is the starting point to locate Devices. It shall either directly or indirectly reference all instances of a subtype of ComponentType with a Hierarchical Reference. For complex Devices that are composed of various components that are also Devices, only the root instance shall be referenced from the DeviceSet Object. The components of such complex Devices shall be locatable by following Hierarchical References from the root instance." | OPC 10000-100 (DI) 1.05.0, 4.9 | | AutoID device types are "Subtype of DeviceType defined in OPC 10000-100". OPC 30010 does not mention `DeviceSet`, Machinery or `Machines`. | OPC 30010 (AutoID) 1.01, 6.1 Table 7 | | "Each Machine providing this building block provides the Components Object, which directly references all identifiable components of a Machine." / "Note: That does not preclude that a Machine is organizing its components in various other hierarchies as well." | OPC 40001-1 (Machinery) 1.04.2, 11.1 | | "The MachineComponentsType provides HasComponent References to all identifiable components of a Machine"; Table 27: `0:HasComponent Object <Component> 0:BaseObjectType OP`; Table 28: `<Component> 0:HasAddIn Object 2:Identification MachineryItemIdentificationType M`; "As all identifiable components shall contain the Identification Object". | OPC 40001-1 1.04.2, 11.2 | | `MachineryItemIdentificationType`: `2:Manufacturer` M, `2:SerialNumber` M, all other members O. | OPC 40001-1 1.04.2, 8.3 Table 16 | | `MachineryComponentIdentificationType` is the component subtype of `MachineryItemIdentificationType` (adds `2:DeviceRevision`); "It is not recommended to use the optional Properties 2:RevisionCounter and 2:DeviceManual"; a missing component `2:ProductInstanceUri` "shall be omitted". | OPC 40001-1 1.04.2, 10.2 | | "it is recommended to keep this approach and let several References lead to the same Node, rather than duplicating the Node" / Robotics example: identification Properties "are only referenced from the Identification functional group". | OPC 40001-1 1.04.2, 7.3 and Annex B.2 (informative) | | "It is expected that domain-specific companion specifications using this specification will define what assets of the domain in what usage are considered to be Machines or components of Machines." | OPC 40001-1 1.04.2, 11.1 (Note) | | Organizes "can be used to span multiple hierarchies"; more than one hierarchical path to a Node is allowed. | OPC 10000-3 1.05, 7.11, 7.5 | **SDK decisions** (not specified by OPC 30010, which predates Machinery): - A reader is never added to `Machines`: no specification classifies an AutoID device as a machine (40001-1 11.1 leaves that to the domain specifications, AutoID is silent). - A reader becomes a component of a machine only when the application asks for it (`AsComponentOf`). - `WithParent` keeps its parent and adds the `DeviceSet` reference rather than rejecting parents outside `DeviceSet` (see below). - The component `Identification` references the reader's nameplate instead of copying it. - AutoID does not add Machinery conformance units; the Machinery owner advertises them for what its builders created. ### Why `WithParent` adds a reference instead of rejecting DI 4.9 asks for reachability, not for a particular parent, and OPC 10000-3 allows several hierarchical paths to one node. Adding `Organizes` from `DeviceSet` satisfies the "shall" while keeping the parent the application asked for, and it is the same reference type `DeviceSet` already uses for every reader (and the DI node manager for every device). Rejecting such parents with `Bad_ConfigurationError` would break existing callers that hang a reader below a machine or folder. When `DeviceSet` already reaches the parent, no reference is added, so the "only the root instance" rule of 4.9 holds for composed devices. Reachability is decided once when the reader is built, by following the forward hierarchical references of the owner's nodes. ### Why `AsComponentOf` keeps the reader referenced from `DeviceSet` Machinery does not require machines to be in `DeviceSet` (the stock builders put them in `Machines` only), so a reader that is only below `Components` would again be unreachable from `DeviceSet`. The same reachability rule as for `WithParent` applies: if the machine is itself reachable from `DeviceSet` (for example a machine that is also a DI device organized by `DeviceSet`), the reader is reached through it and gets no direct reference, otherwise `DeviceSet` organizes it. ### Shape of `AsComponentOf` It takes the machine's `BaseObjectState`, like `WithParent(NodeState)` and `IMachineryBuildContext.BindMachine(TState, ...)`; with the stock builders that is `IMachineHandle<TState>.State`. It requires the machine's `Components` add-in to exist (`IMachineBuilder.WithComponents`, or a companion-declared one bound with `WithComponents(components, ...)`) instead of creating one, so the Machinery builders stay the only place that creates Machinery building blocks (`MachineryBuildingBlocks` organization, facets). The reader's NodeState parent is the `Components` object, so the DI node manager attaches it with `HasComponent` and the existing registration and rollback code applies unchanged. ## Behaviour change for existing callers - `WithParent(parent)` with a parent that `DeviceSet` does not reach (for example a machine in `Machines`, or an application folder): the reader is now *also* browsable from `DeviceSet` (one extra `Organizes` reference, both directions), and an `AutoIdClient.EnumerateReadersAsync()` (which browses `DeviceSet`) now finds it. Its parent, NodeId and `HasComponent` reference are unchanged. - `WithParent(parent)` with a parent `DeviceSet` reaches (for example another reader): unchanged. - Default placement: unchanged. - `IAutoIdReaderBuilder` gains a member. The interface is implemented only inside the package (instances come from `AutoIdRuntime.Reader`), and the package is new in 2.0. ## Changes - `src/Opc.Ua.AutoID.Server/AutoIdReaderPlacement.cs` (new, internal): `DeviceSet` lookup, the reachability check, the `Organizes` reference and its removal, `Components` resolution and validation, the nameplate check, and the `Identification` add-in. - `src/Opc.Ua.AutoID.Server/AutoIdRuntime.cs`: the builder's nameplate delegate runs once (validated before anything is registered, then copied into the DI builder); `AsComponentOf` resolves `Components` as the parent before the device is created; after registration the add-in is added and the `DeviceSet` reference kept; rollback removes the reference. - `src/Opc.Ua.AutoID.Server/Builders/IAutoIdReaderBuilder.cs`, `AutoIdReaderBuilder.cs`: `AsComponentOf`, mutual exclusion with `WithParent`, XML docs stating the exact behaviour. - `docs/AutoID.md`: new "Placement" subsection under "Hosting readers" (what DI 4.9 and Machinery 11 require, what is an SDK decision, a table per builder call, an example), the composition table rows for readers and `Machines`, the test fixture table. `src/Opc.Ua.AutoID.Server/NugetREADME.md`: a short paragraph. - Tests (below). ## Tests - `AutoIdReaderLifecycleTests` (stand-alone owner): `ReadersCanHangBelowAnExplicitParentAsync` now also asserts that `DeviceSet` does not organize a reader below another reader; `AReaderBelowAParentOutsideTheDeviceSetIsStillOrganizedByItAsync`; `AFailedCreationBelowAnOutsideParentLeavesNoDeviceSetReferenceAsync` (rollback); `AStandaloneReaderCannotBeAComponentOfAMachineAsync` (`Bad_ConfigurationError` naming `AddAutoIdToMachinery`); argument checks for `AsComponentOf(null)` and both call orders of `WithParent`/`AsComponentOf`. - `AutoIdCompositionTests` (Machinery owner, in process): `AReaderBecomesAComponentOfAMachineAndStaysADeviceAsync` (parent is `Components`, `HasComponent`, `DeviceSet` organizes it, `Machines` does not, `Identification` with `HasAddIn` and the component type, `HasProperty` to the reader's own `Manufacturer`/`SerialNumber`/`Model` nodes, no `DeviceManual`, owned subtree); `AComponentNeedsAMachineWithComponentsAndRegistersNothingOtherwiseAsync`; `AComponentNeedsTheMandatoryIdentificationAsync`; `AComponentNeedsAMachineOfTheOwnerAsync`; `AFailedComponentCreationIsRolledBackAsync`. - `AutoIdPlacementEndToEndTests` (new, hosted Machinery + AutoID over a real session): a default reader, a reader below that reader, a reader `AsComponentOf` a machine and a reader `WithParent` the machine. Browsing `DeviceSet` finds the three roots and not the nested reader, the outer reader reaches the nested one; `MachineryClient.DiscoverMachinesAsync` returns only the machine and `Machines` contains no reader; `MachineryClient.EnumerateComponentsAsync` lists only the component reader, `ReadIdentificationAsync` reads `Manufacturer`, `SerialNumber`, `ProductCode` through the add-in, which is `HasAddIn`-referenced and typed `MachineryComponentIdentificationType` and whose `HasProperty` targets are the reader's own nameplate nodes; `AutoIdClient.EnumerateReadersAsync` finds the three roots. - The existing default assertions (`TheReadersShareTheDeviceSetWithThePumpAndStayOutOfTheMachinesFolderAsync`, `TheMachineryAndPumpsClientsStillFindTheirInstancesAsync`, `ComposedReadersLiveBelowTheSharedDeviceSetAsync`) are unchanged. - Fail-without: with the runtime wiring reverted to master (builder surface kept so the tests compile), 10 of the new tests fail: all `AsComponentOf` cases, both `WithParent` cases outside `DeviceSet` and the three session tests that look for the component or the extra `DeviceSet` reference. Removing only the rollback of the `DeviceSet` reference makes both rollback tests fail. `NoReaderBecomesAMachineAsync` and the existing default tests pass with and without the change, as intended. Local results (macOS arm64, SDK 10.0.402, head `238ed9b69` on master `9bfc780e1`; the same three commits are now based on master `ac24123dd` as `c6d70909b`, no AutoID file changed in between): `Opc.Ua.AutoID.Tests` net10.0 318/318 passed; `Opc.Ua.AutoID.Server` all TFMs and the test project with `CustomTestTarget=net48` build with 0 warnings, 0 errors (net48 tests run on Windows CI; there is no mono host here). `dotnet format whitespace/style/analyzers --verify-no-changes` on the changed files: no new findings beyond the conventions of the surrounding test files. ## Commits 1. `fix(autoid): keep every reader reachable from DeviceSet` 2. `feat(autoid): make a reader a component of a machine` 3. `docs(autoid): document where readers are placed` The branch is based on OPCFoundation/master `ac24123dd` (#4852, the last master commit with a green build). Fork CI was not repeated on this head: earlier fork runs of this branch failed only in test projects outside this PR (the master build was broken by the NUnit 5 migration #4840 and fixed in #4852; master is currently broken again in `Opc.Ua.Core.Tests` by #4849). The upstream checks of this PR test it against the current master. ## Related Issues - Follow-up to #4825 (tracking issue #4824). - #4823 (open) edits prose in other paragraphs of `docs/AutoID.md` (table of contents, the DI-owner paragraph, providers). This PR adds a subsection and changes two rows of the composition table and one row of the test table; no hunk overlaps. The table of contents is deliberately not touched here because #4823 adds the subsection entries for "Hosting readers"; the "Placement" entry can be added there or after both are merged. ## Checklist - [x] I have signed the [CLA](https://opcfoundation.org/license/cla/ContributorLicenseAgreementv1.0.pdf) and read the [CONTRIBUTING](https://github.com/OPCFoundation/UA-.NETStandard/blob/master/CONTRIBUTING.md) doc. - [x] I have added tests that prove my fix is effective or that my feature works and increased code coverage. - [x] I have added all necessary documentation. - [x] I have verified that my changes do not introduce (new) build or analyzer warnings. (Local build of the changed projects: 0 warnings, 0 errors.) - [ ] I ran **all** tests locally using the **UA.slnx** solution against at least .net **framework** and .net **10**, and all passed. (Locally the AutoID test project on net10.0; net48 is built but runs only on Windows CI.) - [ ] I fixed **all** failing and flaky tests in the CI pipelines and **all** CodeQL warnings. (Pending the upstream checks; see the CI note above.) - [x] I have addressed **all** PR feedback received. --------- Co-authored-by: Marc Schier <marcschier@users.noreply.github.com>
OPC UA .NET Standard stack documentation
These guides lead from a first working application to advanced and experimental capabilities. Follow the numbered stages when you are learning. Choose only the paths that match your application, or use the contents list to find a feature.
- New to the SDK? Start with Getting started, read OPC UA concepts, then build your first information model.
- Upgrading from 1.5.x? Read What's New in 2.0, then follow the Migration Guide.
- Contributing to this repository? See Contributing and maintaining the SDK.
Contents
- How to use this index
- 1. Get started
- 2. Build your application
- 3. Add data types and application services
- 4. Use companion models
- 5. Prepare for production
- 6. Advanced integration, reliability, and scale
- 7. Draft and experimental capabilities
- Reference and upgrade
- Contributing and maintaining the SDK
How to use this index
Each stage builds on the earlier ones, but you do not need to read every guide. After stage 1, choose the client, server, or PubSub path. Stages 3 to 7 are optional; use the guides your application needs. A stage or group names the knowledge it assumes.
Labels describe the maturity of a package or model:
- Preview package: the package family keeps a
-previewversion, even when the core packages are stable. See Versioning. - Draft model: the guide implements a working-group draft specification. Its namespace URIs and NodeIds are provisional.
- Experimental: the guide marks the feature as experimental.
These labels are independent of difficulty. An advanced guide can describe a stable feature, and a released specification can ship in a preview package.
1. Get started
Run a client and server, then learn the terms that the other guides use.
- Getting started — run the minimal samples, or build a client and server from NuGet packages.
- OPC UA concepts — applications, endpoints, sessions, the address space, values, subscriptions, and PubSub.
- Your first information model — add a model to the Getting started server, then read, write, and call it from the client.
- Sample catalogue — minimal, reference, PubSub, and companion-model applications.
- Packages and supported platforms — choose packages and target frameworks.
2. Build your application
Choose the path for your application. The paths are independent: for example, a PubSub application needs neither a client nor a server.
Client path
Assumes Getting started.
- Dependency injection: client feature — configure a client in the .NET Generic Host.
- Managed sessions — connect, recover from connection loss, and close. To compare the managed and classic session APIs, see choosing a session API.
- Read, write, and call methods — resolve namespace URIs and browse paths, check the status of each operation, and call methods through a client generated from the model.
- Subscriptions — callback subscriptions for long-lived monitoring and streams for short observations.
- Generation-bound requests — retain remote file handles, history cursors and target classifications without following a replacement connection.
Server path
Assumes Getting started.
- Dependency injection: server feature — host a server and configure its endpoints, security, and node managers.
- Node managers: start with a model — generate a node manager from your model and attach callbacks. Complete method invocation results covers ordered output values and resolved operation/input diagnostics. Your first information model is a complete example.
- Runtime NodeSets — load NodeSet2 models without generated code when models change independently of your application.
- Asynchronous server support — implement service and node-manager callbacks asynchronously.
PubSub path
A PubSub application needs neither a client nor a server, so the Getting started exercise and the other two paths are optional here.
- Concepts: client/server and PubSub — publishers, subscribers, and datasets.
- Run a first publisher and subscriber — exchange signed and encrypted messages on one computer with the reference PubSub sample.
- PubSub guide — the fluent builder, hosting, configuration, encodings, and security.
- Transport selection — UDP, Ethernet, MQTT, and Kafka.
3. Add data types and application services
Assumes the client or server path. Choose the capabilities your application needs.
Data types and models
- Source-generated data types — generate encodeable implementations for your own structures.
- Complex types — decode server-defined structures and enumerations at run time.
- Model dependencies — compose models that depend on other models.
- NodeId assignment — control the identifiers of nodes created at run time.
- Schema generation — produce XSD, BSD, and JSON schemas for data types.
Application services
- State machines — define, drive, and observe state transitions.
- Programs — host and control Part 10 invocations, monitor captured transition results, and manage diagnostics and lifetime.
- Alarms and conditions — raise, acknowledge, and stream alarms. Alarm conditions use state machines, for example for shelving.
- Historical access — store and read value and event history.
- Aggregates — calculate processed history; read historical access first.
- File system client — transfer files through the standard file objects.
- Alias names — find nodes through named aliases.
- Node management — let clients add and delete nodes and references.
- Final-value publication — await terminal Value notifications in real Publish responses before removing dynamic subtrees.
- Model change tracking — keep client caches current when the address space changes.
- NodeSet export — export a server's address space to NodeSet2 XML.
4. Use companion models
Companion specifications define models for particular industries and device types; Concepts explains how they relate to the base model. These libraries assume the server path and, for typed client access, the client path. The packages load the models that each model depends on.
- Device Integration (OPC 10000-100) — devices, topology, and locking.
- Asset Management Basics (OPC 10000-110) — make devices, machines, pumps or scales manageable assets: discovery, identification, health alarms, maintenance, documentation links and locations. Read Device Integration first.
- Software update (OPC 10000-100) — software package storage, installation, and confirmation. Read Device Integration first.
- ISA-95 (OPC 10030 and OPC 10031-4) — the common model and job control.
- Positioning (OPC 10000-210 and OPC 10000-211; preview package) — relative frames and geographic positions.
- Machinery (OPC 40001-1, -2, -3, -4 and -101) — machines with identification, server-driven state machines, process values, job management, energy and result transfer, based on the Industrial Automation, Device Integration, PA-DIM, ECM and ISA-95 models.
- Pumps (OPC 40223) — pumps and vacuum pumps, published both as Device Integration devices and as Machinery machines.
- AutoID Devices (OPC 30010) — RFID, OCR, optical, optical verifier and RTLS readers: model, server hosting with a provider contract for the reader hardware, typed client, MCP tools and a simulated RFID reader sample, based on the Device Integration model.
- Machine Vision (OPC 40100-1 and OPC 40100-2) — released control, recipes, configurations, results, assets, and condition monitoring, with Vision/Perception composition and Machinery hosting.
- MachineTool and wireless peripherals (OPC 40501-1 and OPC 40505) — machine monitoring, tools, production/jobs/files and independently hosted wireless measurements, configuration and records in one package family.
- Geometric Measurement Systems (OPC 40210) — native measurement equipment, qualification/calibration, production observations and results. The guide documents the upstream undefined Production-statistics CU exception.
- Cranes and Hoists (OPC 40020-1; preview packages) — Robotics-derived crane systems, equipment observations and explicitly authorized speed-limit requests.
- Scales (OPC 40200 and OPC 30050) — weighing technology with every scale kind, scale systems, recipes and PackML state machines, based on the Machinery model.
- Plastics and rubber capabilities (OPC 40083 and OPC 40082-6) — shared machine configuration, control and monitoring, with production dataset transfer and granulate drying.
- Extrusion (OPC 40084-1 through -12) — the extrusion line and its device families, optional capabilities, typed clients and composition.
- Robotics (OPC 40010-1; preview package) — motion-device systems, based on the Industrial Automation and Device Integration models. The guide's draft Robot Intent model is listed in stage 7.
- WoT connectivity (OPC 10100-1; preview package) — connect Web of Things assets. Its registry extension is listed in stage 7.
For more examples, including the Pumps and Machinery models, see the companion-model samples. The generic recycling simulation combines a causal production model with separately hosted process views; its guide identifies the remaining companion integration limits. The optional recycling operator console adds a local ASP.NET Core 10 browser schematic, strict UA trust and role-limited commands; its guide covers standalone and Compose setup, image publication and the synthetic sample's operational/security limits.
To expose these typed client interfaces to an agent, use the industrial companion MCP tools. Select one family or compose several profiles without enabling the entire tool catalog. The WoT and xRegistry profiles cover asset/registry management and document conversion; the document profile does not require a UA connection.
5. Prepare for production
Builds on the certificate trust you used in Getting started. Before you deploy a client or server, work through the production readiness checklist. It links to these guides for the details:
- Certificates — certificate stores, trust, and chain validation.
- Identity providers — authenticate users on clients and servers.
- Role-based user management — map identities to roles and permissions.
- Certificate manager — certificate lifecycle, rotation, and remote updates.
- Diagnostics — logging, metrics, tracing, auditing, and packet capture.
- Rate limiting — admission limits and busy signals during connection storms.
- Server resource isolation — per-caller limits and reserved capacity for startup and recovery.
- Profiles and facets — implemented profiles and platform boundaries.
- Container reference server — run the reference server in a container.
6. Advanced integration, reliability, and scale
Each group names the stages it assumes.
Transports and integration
Assumes the client or server path.
- Transports — UA-TCP, HTTPS, and WebSocket transports.
- REST binding — OpenAPI mapping, encoding negotiation, and HTTP authentication.
- OPC UA over OpenAPI — serve the OpenAPI document the stack generates from its REST routes and call the server from generated REST clients.
- Reverse Connect — server-initiated connections.
- Session-less invocation — let clients call Read, Browse, Call and the other §6.3 Services without a Session.
- PubSub external-server adapter — bind PubSub to an OPC UA server through a managed client session. Assumes the client and PubSub paths.
- PubSub transcoding — convert encodings, values, and metadata between PubSub messages.
- MCP server — let AI agents browse, read, write, and diagnose OPC UA servers. Stack workflow profiles add GDS/credential issuance, roles/users, files, alarms, history, schemas, policy-controlled PubSub and live WoT execution.
- WoT / NodeSet conversion and WoT protocol bindings — convert Thing Descriptions and add protocol bindings. Read WoT connectivity first.
Session recovery and performance
The subscription guides assume the client path; the sizing guides assume Diagnostics.
- TransferSubscriptions — move server subscriptions to a new session.
- Durable subscriptions — keep subscriptions and queued notifications while clients are disconnected.
- Generation-bound session clients — capture dispatch, session identity and mapping snapshots without reconnecting to a replacement peer.
- Server scalability — sizing limits and bottlenecks.
- Benchmarks — measured performance and methodology.
Security infrastructure and fleet management
Assumes stage 5.
- ECC profiles — elliptic-curve security policies and their platform requirements.
- Crypto providers — replace the platform cryptography and keep private keys in hardware.
- Provisioning mode — configure a new server securely before exposing application data.
- Global Discovery Server — application registration and central certificate management.
- GDS sample — a runnable onboarding workflow.
- AuthorizationService — issue access tokens.
- KeyCredentialService — manage credentials for services that are not OPC UA. Its issued-token bridge is listed in stage 7.
High availability and deployment
Assumes a working single server and stage 5.
- High availability (preview package) — redundancy, failover, and distributed state.
- Replica-consistent NodeIds (preview package) — keep node identifiers identical across replicas; required before replicating an address space.
- Kubernetes (preview package) — cluster deployment, discovery, readiness, and secrets. Read high availability first.
- PubSub high availability (preview package) — redundant publishers and subscribers. Assumes the PubSub path.
Native AOT publishing
Publish an application as a native executable without a JIT compiler; start with Native AOT: publish an application. Feature-specific guidance:
- Servers with generated node managers
- Applications hosted with dependency injection
- PubSub applications
7. Draft and experimental capabilities
These guides implement working-group drafts or experimental extensions. Namespace URIs, NodeIds, and APIs can change before the specifications are published, so evaluate them before you depend on them in production. Each guide describes its current limitations.
- xRegistry (draft model; preview package) — the generic registry base model, resource storage, and federation.
- AI model management (draft model; preview package) — model catalogues, deployments, inference, and learning jobs. Builds on xRegistry.
- Perception model (draft model; optional OpenUSD renderer is preview-only) — capture, media, feedback, and client workflows.
- Robot Intent (draft model; preview package) — task-level motion commands. Does not require the Robotics model.
- OpenUSD (draft models; preview package) — bind values to OpenUSD scenes and materialize scenes in the address space.
- WoT Connectivity registry (draft model; preview package) — hosting, document provisioning, and refresh.
- WoT-Con 1.02 compatibility — existing-type bindings, declarations, and original document preservation.
- WoT design and provider contracts — exact-Version dependencies and leases, prepared storage/publication, and recovery.
- KeyCredential issued-token bridge (experimental).
These samples combine several draft or preview capabilities. Read the guides for their models first:
- Bin picking cell — Robot Intent, Vision, and an OpenUSD scene.
- Visual inspection cell — Vision, AI model management, and ISA-95 job control.
- WoT aggregation sample — load Device Integration, Machinery, and Pumps models from WoT documents through the WoT Connectivity 1.1 registry, and bind them to two OPC UA source servers.
- Generator sample model (draft model) — generating-set simulation and scene composition.
Reference and upgrade
- What's New in 2.0 — a summary of new capabilities.
- Migration Guide — upgrade from 1.5.378, with topic-specific 2.0 guides and PubSub migration.
- Reference client — command-line configuration and transport profiles.
- Reference server — hosting and compliance-test setup.
- Reference PubSub client — publisher, subscriber, and external-adapter modes.
The Windows Forms reference applications are maintained in the Samples repository.
Contributing and maintaining the SDK
These documents describe building and maintaining this repository, not using the SDK in an application:
- Developer Guide — prerequisites, build, tests, and coding conventions.
- Continuous integration — pipelines and coverage gates.
- Native AOT test harness — build, run, and extend the Native AOT compatibility tests.
- Release process — release branches, versioning, backports, and recovery.
- Redundancy sample tests — process-level failover and soak validation.
- Fuzz testing — encoder, certificate, and network campaigns.