Comment on page
The technical architecture of OpenCRVS was designed to conform to the Open Health Information Exchange (OpenHIE) architectural standard and interoperate using HL7 (Fast Healthcare Interoperability Resources) or FHIR. FHIR is a global standard application programming interface or (API) for exchanging electronic health records.
By following the OpenHIE framework, OpenCRVS seamlessly connects civil registration to health services and other systems. Firstly, by utilising the OpenHIE interoperability reference middleware OpenHIM, a FHIR standard enterprise service bus; and secondly, by using a scalable, modular, NoSQL FHIR datastore, called Hearth.
OpenCRVS business functions are designed using modular, event-driven microservices. Each micro service and every OpenCRVS component is independently scalable in private or public cloud, in large or small data centres, and easy to manage, load balance and network using included Docker Swarm configurations.
OpenCRVS builds on these sound principles by additionally providing:
- Easy country configuration via simple csv files and a configuration UI.
- Standards-based multi-language content management.
- An automated continuous integration, delivery and testing suite.
- SMS 2-Factor Authentication with well defined user role authorization privileges
Our international development teams work in an Agile way, in tandem with local development resources and human-centred designers, following the Scrum methodology, to rapidly design, build, deploy, test and maintain OpenCRVS releases.
Application services and network diagram.png
Docker Swarm was chosen by our architects in 2018 for it's lack of requirement of other essential dependencies, it's close alignment with Docker and it's simplicity in terms of installation and monitoring on a Tier 2 private data centre, on bare metal servers with headless Ubuntu OS. Why not use AWS, public cloud SaaS or serverless you might be thinking?
- Many countries may be located far from a high-quality data-centre above Tier 2.
- Many countries may not legally support international data storage of citizen data on a public cloud. Getting the legal approval for external storage of citizen data requires regulatory change which can take a considerable amount of time.
- Because some countries may not be able to maintain complex software independently, we are considering a SaaS solution, provided enough countries get regulatory approval. Over time, this situation appears to be slowly evolving and we are monitoring it closely.
Previously unskilled system administrators can quickly up-skill in the techniques of private cloud infrastructure management using Docker Swarm. We wanted to democratise containerisation benefits for all countries.
We are working on a Kubernetes migration now that Kubernetes has become a more mature, easier to use and configure solution, thanks to dependencies like Helm and other plugins increasing popularity since 2018. In the meantime, Docker Swarm makes it easy to commence containerised microservice package distribution privately, automatically configures a "round robin" load balanced cluster, and provides Service Discovery out-the-box.
Hearth MongoDB Database layer
OpenCRVS uses ElasticSearch, an industry standard, NoSQL document orientated, real-time de-duplication & search engine. Lightning fast, intelligent civil registration record returns are possible, even with imprecise “fuzzy” search parameters.
De-duplication management to ensure data integrity is essential to any civil registration system. A fast search engine lowers operational costs and improves the user experience for frontline staff.
The hyper-efficient Influx "time series database" is used in our stack for "big data" performance insights. Millisecond level query times facilitate civil registration statistical queries over years of data, disaggregated by gender, location and configurable operational and statistical parameters. \
OpenHIM enterprise service bus, interoperability Layer
The OpenHIM (Health Information Mediator) is a NodeJS enterprise service bus designed to ease interoperability between OpenCRVS and external systems such as Health & National ID. It provides external access to the system via secure APIs. OpenHIM channels and governs internal transactions, routing, orchestrating and translating requests into FHIR between services and the database layer.
The OpenCRVS microservice architecture enables continuous evolution of its business requirements.
- gateway - the GraphQL and Apollo API gateway for the OpenCRVS client. GraphQL allows OpenCRVS to perform much faster and more responsively in remote areas by drastically reducing the number of HTTP requests that are required in order to render a view in the presentation layer. The OpenCRVS GraphQL Gateway is a JWT protected Apollo server that requests and resolves FHIR resources from Hearth via OpenHIM into GraphQL, for easy consumption in the client applications.
Because the OpenCRVS Form UI is configurable to your country, the end-to-end testing scripts are located in our example country configuration server for Farajaland so you can copy this approach and customise them depending on the structure of your published form.