This document explains how to get started with log aggregation for Scalar products on Kubernetes using Grafana Loki (with Promtail).

We assume that you have already read the getting-started with monitoring for Scalar products and installed kube-prometheus-stack.

What we create

We will deploy the following components on a Kubernetes cluster as follows.

+--------------------------------------------------------------------------------------------------+
| +------------------------------------+                                                           |
| |             loki-stack             |                                                           |
| |                                    |                                       +-----------------+ |
| | +--------------+  +--------------+ | <-----------------(Log)-------------- | Scalar Products | |
| | |     Loki     |  |   Promtail   | |                                       |                 | |
| | +--------------+  +--------------+ |                                       |  +-----------+  | |
| +------------------------------------+                                       |  | ScalarDB  |  | |
|                                                                              |  +-----------+  | |
| +------------------------------------------------------+                     |                 | |
| |                kube-prometheus-stack                 |                     |  +-----------+  | |
| |                                                      |                     |  | ScalarDL  |  | |
| | +--------------+  +--------------+  +--------------+ | -----(Monitor)----> |  +-----------+  | |
| | |  Prometheus  |  | Alertmanager |  |   Grafana    | |                     +-----------------+ |
| | +-------+------+  +------+-------+  +------+-------+ |                                         |
| |         |                |                 |         |                                         |
| |         +----------------+-----------------+         |                                         |
| |                          |                           |                                         |
| +--------------------------+---------------------------+                                         |
|                            |                                                                     |
|                            |         Kubernetes                                                  |
+----------------------------+---------------------------------------------------------------------+
                             | <- expose to localhost (127.0.0.1) or use load balancer etc to access
                             |
              (Access Dashboard through HTTP)
                             |
                        +----+----+
                        | Browser |
                        +---------+

Step 1. Prepare a custom values file

  1. Get the sample file scalar-loki-stack-custom-values.yaml for the loki-stack helm chart.

Step 2. Deploy loki-stack

  1. Add the grafana helm repository. 
    helm repo add grafana https://grafana.github.io/helm-charts
  2. Deploy the loki-stack helm chart. 
    helm install scalar-logging-loki grafana/loki-stack -n monitoring -f scalar-loki-stack-custom-values.yaml

Step 3. Add a Loki data source in the Grafana configuration

  1. Add a configuration of the Loki data source in the scalar-prometheus-custom-values.yaml file. ```yaml grafana: additionalDataSources:
    • name: Loki type: loki uid: loki url: http://scalar-logging-loki:3100/ access: proxy editable: false isDefault: false ```
  2. Apply the configuration (upgrade the deployment of kube-prometheus-stack). 
    helm upgrade scalar-monitoring prometheus-community/kube-prometheus-stack -n monitoring -f scalar-prometheus-custom-values.yaml

Step 4. Access the Grafana dashboard

  1. Add Loki as a data source
    • Go to Grafana http://localhost:3000 (If you use minikube)
    • Go to Explore to find the added Loki
    • You can see the collected logs in the Explore page

Step 5. Delete the loki-stack helm chart

  1. Uninstall loki-stack. 
    helm uninstall scalar-logging-loki -n monitoring