Added Documentation

Author: jmanuelcorral

elk/Readme.md

@@ -0,0 +1,28 @@
+This article contains a brief introduction to centralized structured logging with [Serilog](https://serilog.net/) and event viewing with [ELK](https://www.elastic.co/elk-stack) in eShopOnContainers. ELK is an acronym of ElasticSearch, LogStash and Kibana. This is one of the most used tools in the industry standards.
+
+![](img/elk/kibana-working.png)
+
+## Wiring eshopOnContainers with ELK
+
+eshopOnContainers is ready for work with ELK, you only need to setup the configuration parameter **LogstashgUrl**, in **Serilog** Section, for achieve this, you can do it modifing this parameter in every appsettings.json in every service, or via Environment Variable **Serilog:LogstashUrl**.
+
+There is another option, a zero-configuration environment for testing the integration launching via ```docker-compose``` command, on the root directory of eshopOnContainers:
+
+```sh
+docker-compose -f docker-compose.yml -f docker-compose.override.yml -f docker-compose.elk.yml
+```
+
+### Configuring Logstash index on Kibana
+
+Once time you have started and configured your application, you only need to configure the logstash index on kibana.
+You can address to Kibana, with docker-compose setup is at [http://localhost:5601](http://localhost:5601)
+
+If you have accessed to kibana too early, you can see this error. It's normal, depending of your machine the kibana stack needs a bit of time to startup.
+![](img/elk/kibana_startup.png)
+
+You can wait a bit and refresh the page, the first time you enter, you need to configure and index pattern, in the ```docker-compose``` configuration, the index pattern name is **eshops-\***.
+![](img/elk/kibana_eshops_index.png)
+
+With the index pattern configured, you can enter in the discover section and start viewing how the tool is recollecting the logging information.
+
+![](img/elk/kibana_result.png)