Hello Hassnan,
For a standalone alerting service you don't need to install the full Hawkular Services. Installing the Hawkular Alerting component could be enough.
Also, the master branch hosts the version 2.x that doesn't depend on cassandra, so, installation should be easy.
There are some docker images for hawkular alerting, but those are just for pure demo purposes, so I would recommend to build the project, getting familiar with the examples and personalize with your scenario.
Note that this component is not under active development but if it is interesting to you, feel free to send your PRs or suggestions.
Lucas Ponce