Egeria Planning Guide - How to deploy Egeria into your organization
The planning guide provides information to help you plan the deployment of Egeria in your organization.
Egeria is highly flexible and configurable and so the first piece of advice is to start small and simple and then expand as your experience and understanding of your workloads grows.
Platforms and Servers
Figure 1 shows the diagram from Egeria’s home page showing Egeria exchanging metadata between many types of tools distributed across different data centers and cloud platforms.
Figure 1: Egeria integrating different tools distributed over many locations
The green clouds represent each of the deployment locations. The different technologies are shown as grey boxes and Egeria itself is shown in blue and orange.
The blue rounded boxes are Egeria’s Open Metadata and Governance (OMAG) Server Platform. This platform is the heart of Egeria’s implementation. Typically you would expect to have at least one OMAG Server Platform deployed in each location. However, when you are experimenting with Egeria, it is often sufficient to start with one OMAG Server Platform and expand the number of platforms as you expand the technologies being integrated.
The OMAG Server Platform is capable of hosting one or more Open Metadata and Governance (OMAG) Servers. The OMAG Servers are the orange circles in Figure 1. They manage the connectors to third party technology as well as the frameworks and intelligence that Egeria brings to distributed metadata management.
It is a simple command to move an OMAG Server from one platform instance to another. This means you can start experimenting with a single platform and then add more as your deployment grows. The platform can also run as a node in container technologies such as Docker and Kubernetes.
Figure 2: OMAG Server deployment choices
Different types of technology need different types of integration and Egeria has OMAG Servers to match. Each type of OMAG Server is focused on the integration of a specific type of tool, engine or platform. Figure 3 shows the OMAG Servers implemented today and how they are classified. This picture will expand as Egeria embraces new types of technology.
Figure 3: Types of OMAG Servers
The way to understand the diagram is that the arrows should be read as IS A. For example, the Repository Proxy IS A Cohort Member and the Cohort Member IS A OMAG Server. This means that everything documented about a particular type of server is also true for all server types that point to it through the IS A arrow, all of the way down the hierarchy.
Object-oriented software engineers would know of this type of relationship as behavior inheritance.
The cohort members communicate with one another via an open metadata repository cohort. This means that they exchange metadata through a low level, fine-grained API supported by the Open Metadata Repository Services (OMRS). Click here to see details of the protocol.
The Open Metadata Access Services (OMASs) are built on top of the repository services. They live in the metadata access point/metadata servers. They offer more course-grained interfaces, specialized for particular types of technology. Click here to see the full list.
The governance servers are again specialized for particular types of metadata integration or additional governance activity. They connect to a metadata access point / metadata server.
Finally the view servers support the services for the solution user interfaces. They also connect to a metadata access point / metadata server.
Figure 4 shows how the servers connect together.
Figure 4: How the OMAG Servers interact
Figure 5 shows that the servers’ integration can be viewed as a series of nested spheres. The inner sphere involves the cohort members and provides metadata exchange between metadata repositories (and conformance test the integrations). The next level out adds the governance servers to automate the exchange of metadata between the metadata repositories and third party tools, engines and platforms. Finally, adding the view server and user interfaces delivers a governance solution to an organization.
Figure 5: Spheres of interaction between OMAG Servers
This architecture means that you can incrementally add function to your deployment. Here is a suggested approach:
Start with creating an Egeria graph metadata server. This will provide a metadata repository that can store any type of open metadata.
Decide on a name for an open metadata repository cohort and add configure your graph metadata repository to join it.
If you want to have other third party metadata repositories that you want to share metadata with, configure repository proxies for each including registering them to the same cohort as the metadata server.
If you then want to add in metadata synchronization with other types of technology beyond metadata repositories, work out which integration daemons you need and configure them to connect to the metadata server. Make sure the appropriate access services for these integration daemons are enabled in the metadata server.
If you want to use the discovery server or stewardship server then these can be connected to the metadata server via the Discovery Engine and Stewardship Action access services respectively.
Finally if you want to deploy the user interfaces, make sure you have at least one view server for the presentation server that hosts the UI application.
Working through this exercise gives you an understanding of the Egeria technology that you need for your deployment and how it connects together.
If you discover that there is a third party technology that is not currently supported by Egeria then you need to build a connector to translate between the APIs and events of that technology and the open metadata APIs and event. This is described in the Developer Guide.
Thinking about the scope of the metadata integration
Another useful planning exercise is to identify the community of users and the tools that they use that need to share metadata. This gives you a view of the technology that needs to be integrated. If each community is fairly self-contained with their own tools deployment then you may want to consider deploying an OMAG Server platform for this community and deploying the servers they need onto it. This means they can control their access to open metadata along with the delivery of open metadata to the rest of the organization.
More importantly, it helps with the definition of the organization’s governance zones.
This is a checklist of planning tasks for the deployment of your OMAG Server Platforms and OMAG Servers.
Use an encrypted configuration document store for your platforms since configuration documents can have certificates and passwords in them more information.
Implement the metadata security connectors for your organization to ensure only authorized users access metadata more information.
Choose and configure the audit log destinations for your OMAG servers more information.
Ensure you have at least one Egeria metadata server in each of your open metadata repository cohorts more information.
Assign a separate user id for each of your servers and ensure they are defined in your user directory and are authorized users according to the metadata security connectors. more information
Consider where you need to have multiple versions of the same server running to give continuous availability more information.
Plan your use of the event bus - which technology to use (Apache Kafka is the default) and the names of the topics that your OMAG Servers will use more information.
Design the governance zones that you want to use to control the visibility of assets to different communities of users - or processes more information.
More detail to follow …
The text above is a very high level overview of the planning process. More detail will be added to this guide as time permits.
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License: CC BY 4.0, Copyright Contributors to the ODPi Egeria project.