The scrum demo application is composed of microservices and provides a example of how microservices implement common application aspects, such as data management, stateful domain objects and reporting in a distributed architecture. It is a useful starting point for a Java engineer who is interesting in understanding how microservices are built.
The application is designed to be deployed within an Openshift cluster and provides a convenient platform for demonstrating aspects such as logging, monitoring, release management and testing for microservices.
One thing to note is that each microservice has its own git repository. Separate repositories means that each service be released independently.
| Repository | Description |
|---|---|
| estafet-microservices-scrum-api-project | Microservices for managing scrum projects. |
| estafet-microservices-scrum-api-project-burndown | Microservices for aggregating and generating project burndown reports. |
| estafet-microservices-scrum-api-sprint | Microservices for managing sprints. |
| estafet-microservices-scrum-api-sprint-board | Microservices for aggregating and rendering a sprint board. |
| estafet-microservices-scrum-api-sprint-burndown | Microservices for aggregating and generating sprint burndown reports. |
| estafet-microservices-scrum-api-story | Microservices for managing stories. |
| estafet-microservices-scrum-api-task | Microservices for managing tasks. |
| estafet-microservices-scrum-api-discovery | Service Discovery for microservices. |
| estafet-microservices-scrum-api-gateway | Microservices API Gateway. |
| estafet-microservices-scrum-basic-ui | Basic User Interface that uses the scrum microservices. |
| estafet-microservices-scrum-lib | Shared Libraries |
| estafet-microservices-scrum-qa | Cross cutting Quality Assurance tests. |
There are a couple of installation options for the demo application:
Please review the prerequisites below before continuing with the deployment steps:
Ansible is installed as a linux application, but it is possible to install it on Windows 10 and Mac OS X machines.
Windows users will need to install ansible using Windows Subsytem for Linux (WSL). For instructions on how to install anisble on a Window 10 machine, please refer to this excellent article.
https://www.jeffgeerling.com/blog/2017/using-ansible-through-windows-10s-subsystem-linux
Mac users can easily install ansible provided homebrew isinstalled. For a comprehensive description, please consult this article.
https://hvops.com/articles/ansible-mac-osx/
The ansible playbook requires a python module that is not always installed with the standard ansible distributions.
sudo apt-get install python-jmespath
The ansible playbook assumes that you have installed Openshift on your local development machine. If this is not the case, you will need to amend the ansible create-local-environment-vars.yml or create-devops-environments-vars.yml file (depending on which environment you are installing) and modify the openshift: 192.168.99.100:8443 directive.
The playbook also assumes that the Openshift CLI oc is installed on the same machine that you have installed Ansible on. If this is not the case, you will need to amend the Ansible microservices-scrum.yml file and modify the hosts: localhost directive.
Windows users will need to install the Openshift CLI onto WSL for linux so that the ansible scripts can run. They will also need to copy the kuberenetes credentials from the windows to WSL. This will alllow the ansible script perform certain operations as the system administrator.
cp /mnt/c/Users/<Windows User>/.kube/config ~/.kube
Installing and configuring the scrum demo application to openshift manually is a lengthy process. There are 13 applications in total (8 microservices + db + jaeger + message broker). Fortunately this process has been automated using Ansible.
Clone the master repository to a directory of your choice.
git clone https://github.com/Estafet-LTD/estafet-microservices-scrum.git
Run the playbook. The playbook takes about 15 mins complete.
Note:- If you are using minishift, it might be advisible to tweak the resources available.
$ cd estafet-microservices-scrum/ansible
$ ansible-playbook create-local-environment-playbook.yml
You can reset the application data by executing the following playbook. This will redeploy all of database dependent microservices so it takes about a 30 seconds to complete.
ansible-playbook reset-data-playbook.yml
The local environment setup allows a developer start using the microservices application, but in order to set up a project, we'll need to create a development, test, continuous integration and project environment. These environments will need CICI pipelines, artifact repositories, code analysis and all of the automation associated with DevOps. Fortunately, this can be setup with running a single script.
Clone the master repository to a directory of your choice.
git clone https://github.com/Estafet-LTD/estafet-microservices-scrum.git
Run the playbook. The playbook takes about 30 mins complete.
Note:- If you are using minishift, it might be advisible to tweak the resources available.
$ cd estafet-microservices-scrum/ansible
$ ansible-playbook create-devops-environments-playbook.yml
Jenkins setup tbc...
tbc...
tbc...
The application consists of 9 microservices + the user interface. These are deployed to openshift as pods. The postgres pod instance contains 6 databases, each "owned" by a microservice. The A-MQ broker processes messages sent to topics and distributes these to microservices that have subscribedtothose topics.
Here's the overall business domain model.
Here's a short summary of the Opentracing and Jaeger with microservices.
This is a more detailed walkthrough of the scrum demo application and it's integration with Jaeger.
