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Logging Stack

This chapter describes how to setup the Kubermatic Kubernetes Platform (KKP) logging stack. It’s highly recommended to install this stack on the master and all seed clusters.

The logging stack consists of Promtail and Grafana Loki. Customers with more elaborate requirements can also choose to install an ELK stack (either via Helm or using the Elastic Cloud on Kubernetes operator).

Requirements

The exact requirements for the stack depend highly on the expected cluster load; the following are the minimum viable resources:

  • 2 GB RAM
  • 2 CPU cores
  • 50 GB disk storage

This guide assumes the following tools are available:

  • Helm 3.x
  • kubectl 1.16+

It is also assumed that the monitoring stack is installed, as its Grafana deployment is used to inspect the aggregated logs from Loki.

Installation

As with KKP itself, it’s recommended to use a single values.yaml to configure all Helm charts. There are a few important options you might want to override for your setup:

  • loki.persistence.size (default: 10Gi) controls the volume size for the Loki pods.
  • promtail.scrapeConfigs controls for which pods the logs are collected. The default configuration should be sufficient for most cases, but adjustment can be made.
  • promtail.tolerations might need to be extended to deploy a Promtail pod on every node in the cluster. By default, master-node NoSchedule taints are ignored.

An example values.yaml could look like this if all options mentioned above are customized:

loki:
  persistence:
    size: '100Gi'

promtail:
  scrapeConfigs:
  - ...

With this file prepared, we can now install all required charts:

Helm 3

helm --namespace logging upgrade --install --wait --values /path/to/your/helm-values.yaml promtail charts/logging/promtail/
helm --namespace logging upgrade --install --wait --values /path/to/your/helm-values.yaml loki charts/logging/loki/

Helm 2

helm --tiller-namespace kubermatic upgrade --install --values /path/to/your/helm-values.yaml --namespace logging promtail charts/logging/promtail/
helm --tiller-namespace kubermatic upgrade --install --values /path/to/your/helm-values.yaml --namespace logging loki charts/logging/loki/