Hello Everybody,

With a growing community and an increasingly large number of sub-projects, it is the perfect time to rethink the packaging of Hawkular. This email is a blueprint for changes to come to Hawkular as well as establish some patterns for futures decisions.

Motivation

So far we have created Hawkular "All-in-one" releases that contain everything, Hawkular server components, UI, the agent and also embedded versions of Cassandra and KeyCloak. It's certainly the case that for community we will still deliver a fully featured all-in-one package. We also need to consider separate distributions for other projects that integrate with Hawkular.

The recent effort to integrate with ManageIQ comes with its own set of requirements for services. Not all of the Hawkular components are needed and required components may be configured differently. For example the UI is supplied from within ManageIQ side and Hawkular is to be run headless. Other components like Cassandra will not run embedded, so there is no need to supply it in an embedded package. KeyCloak will probably not be needed  because we only have one technical user that will access Hawkular services.

Components / Services

Here a list of projects that are part of the Hawkular organization:

• Metrics - scalable, asynchronous, multi tenant, long term metrics storage engine 

• Inventory - registry of "things" that contains info about your applications, servers, etc. and also keeps track of their relationships with each other

• Alerts - alerting engine that allows trigger definitions to evaluate incoming data, generate alerts (or events), and react with flexible actions ond lifecycle management

• CommandGW - messaging framework for communicating between components

• Bus - messaging framework for communicating between components

• BTM - provide capabilities to monitor the flow of a business transaction instance and enable performance analysis of the individual components that make up an application

• Agent - used to monitor WildFly and related projects

• Accounts - is the user/organization module that provides authentication, authorization and configuration for accounts

• Data Mining - alert predictions based on time series data

• Hawkular UI

• Hawkular Charts - Angular Directives for Metrics Visualization

• Embedded Cassandra - embedded Cassandra server specifically configured for project use

There are also various clients like the Ruby Gem or the Android client and supporting infrastructure projects. Those are not part of this discussion.

Options for Packages

The distribution packages need to follow product integrations with a special distribution for community. The community package could potentially include every single package from the Hawkular organization. However, the rest of the packages need to be created along the lines of product use and include only the minimal amount of components, services and third-party libraries to satisfy integration requirements. 

The distributions should be seen as funnels, the Hawkular community creates a set of sub-projects that then get combined into few distributions that in turn get consumed. Following this analogy, the number of packaged distributions should also be kept to a minimum possible. For now we settled on 3 packages detailed below, all will be available for download on JBoss.org.

With the exception of the community distribution:

1) the QA team will be engaged in testing the package

2) the sub-components will strive to be aligned in terms of tech stack and maturity

3) an automated test suite is required for packages that combine more than one project

1. Hawkular - Community Distribution

Will include every single service listed above. The UI is a requirement because some services are very hard to understand or use without a friendly interface. The UI will be a community only effort at this point since there are no plans for productization. 

The current Hawkular repository will be adjusted to reflect this new mission; the current UI will be moved to a separate repository. This package builds on Hawkular Core Services as described next.

2. Hawkular Core Services

Geared towards MiQ integration, it will include only components needed for the MiQ provider. This package uses the Metrics Distribution as described below.

Components included: Metrics, Alerts, Inventory, CommandGW, and Bus

Reasons for some exclusions: Keycloak (different security model), Embedded Cassandra (only full C* deployments will be supported), and no Hawkular UI because it will use a special purpose UI for MiQ.

3. Metrics Distribution

Geared towards usage as a pure Time Series Database (TSDB) and will be exclusively made of Hawkular Metrics service.

Expansion and Contraction

Since its inception Hawkular has been growing by all metrics: projects, lines of code, binary downloads, contributors, etc. But uncontrolled increase in some metrics can be detrimental to the organization. This is especially true for the number of projects. We will always need new projects to experiment, but the reverse might be true for mature and established projects. As the packaging and requirements for each distribution mature we need to consider the reverse, merging separate sub-projects. 

Packaging Format

This email did not touch on the physical packaging formats (rpm, zip, war, jar) for the 3 distributions. We will follow-up with additional details in the coming weeks.

All feedback is more than welcomed so feel free to reach us (Heiko and Stefan) directly or reply to this thread.

Heiko & Stefan