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Sumo Logic

Collect Varnish Logs and Metrics for Kubernetes environments

In a Kubernetes environment, we use the Telegraf Operator, which is packaged with our Kubernetes collection. You can learn more about it here. The diagram below illustrates how data is collected from Varnish in a Kubernetes environment. In the architecture shown below, there are four services that make up the metric collection pipeline: Telegraf, Prometheus, Fluentd, and FluentBit.

The first service in the pipeline is Telegraf. Telegraf collects metrics from Varnish. Note that we’re running Telegraf in each pod we want to collect metrics from as a sidecar deployment, for example, Telegraf runs in the same pod as the containers it monitors. Telegraf uses the Varnish input plugin to obtain metrics. (For simplicity, the diagram doesn’t show the input plugins.) The injection of the Telegraf sidecar container is done by the Telegraf Operator. We also have Fluentbit that collects logs written to standard out and forwards them to FluentD, which in turn sends all the logs and metrics data to a Sumo Logic HTTP Source.

clipboard_e32d2136e47a431a6095f20948eefdcb1.png

Follow the below instructions to set up the metric collection:

  1. Configure Metrics Collection
    1. Setup Kubernetes Collection with the Telegraf operator
    2. Add annotations on your Varnish pods
  2. Configure Logs Collection
    1. Configure logging in Varnish.
    2. Add labels on your Varnish pods to capture logs from standard output.
    3. Collecting Varnish Logs from a Log file.

Prerequisites

It’s assumed that you are using the latest helm chart version. If not, upgrade using the instructions here.

Step 1 Configure Metrics Collection

This section explains the steps to collect Varnish metrics from a Kubernetes environment.

In a Kubernetes environment, we use the Telegraf Operator, which is packaged with our Kubernetes collection. You can learn more on this here. Follow the steps listed below to collect metrics from a Kubernetes environment:

  1. Setup Kubernetes Collection with the Telegraf Operator.

  2. Add annotations on your Varnish pods

On your Varnish Pods, add the following annotations:

 annotations:
    telegraf.influxdata.com/class: sumologic-prometheus
    prometheus.io/scrape: "true"
    prometheus.io/port: "9273"
    telegraf.influxdata.com/inputs: |+
    [[inputs.varnish]]
   use_sudo = true
   binary = "/usr/bin/varnishstat"
   stats = ["*"]
   [inputs.varnish.tags]
    component="cache"
    environment="dev_CHANGME"
    cache_system="varnish"
    cache_cluster="varnish_on_k8s_CHANGEME”

Please enter in values for the following parameters (marked in bold above):

  • telegraf.influxdata.com/inputs - This contains the required configuration for the Telegraf varnish Input plugin. Please refer to this doc for more information on configuring the Varnish input plugin for Telegraf. Note: As telegraf will be run as a sidecar, the host should always be localhost.

    • In the input plugins section, which is [[inputs.varnish]]

      • binary -  The default location of the varnish stat binary. Please override as per your configuration.

      • use_sudo - If running as a restricted user, prepend sudo for additional access.

      • stats - Stats may also be set to ["*"], which will collect all stats. Please see this doc for more information on additional parameters for configuring the Varnish input plugin for Telegraf.

    • In the tags section, which is [inputs.varnish.tags]

      • environment - This is the deployment environment where the Varnish cluster identified by the value of servers resides. For example: dev, prod or qa. While this value is optional we highly recommend setting it. 

      • cache_cluster - Enter a name to identify this Varnish cluster. This cluster name will be shown in the Sumo Logic dashboards. 

Here’s an explanation for additional values set by this configuration that we request you please do not modify as they will cause the Sumo Logic apps to not function correctly.

  • telegraf.influxdata.com/class: sumologic-prometheus - This instructs the Telegraf operator what output to use. This should not be changed.

  • prometheus.io/scrape: "true" - This ensures our Prometheus will scrape the metrics.

  • prometheus.io/port: "9273" - This tells prometheus what ports to scrape on. This should not be changed.

  • telegraf.influxdata.com/inputs

    • In the tags section i.e.  [inputs.varnish.tags]

      • component: “cache” - This value is used by Sumo Logic apps to identify application components. 

      • cache_system: “varnish” - This value identifies the web server system.

For all other parameters please see this doc for more properties that can be configured in the Telegraf agent globally.

  1. Sumo Logic Kubernetes collection will automatically start collecting metrics from the pods having the labels and annotations defined in the previous step. 

  2. Verify metrics in Sumo Logic.

Step 2 Configure Logs Collection

This section explains the steps to collect Varnish logs from a Kubernetes environment.

  1. (Recommended Method) Add labels on your Varnish pods to capture logs from standard output.

Follow the instructions below to capture Varnish logs from stdout on Kubernetes.

  1. Apply following labels to the Varnish pods:

 labels:

environment: "prod_CHANGEME"
component: "cache"
cache_system: "varnish"
cache_cluster: "varnish_on_k8s_CHANGEME

Please enter in values for the following parameters (marked in bold above):

  • environment - This is the deployment environment where the Varnish cluster identified by the value of servers resides. For example: dev, prod or qa. While this value is optional we highly recommend setting it.

  • cache_cluster - Enter a name to identify this Varnish cluster. This cluster name will be shown in the Sumo Logic dashboards.

Here’s an explanation for additional values set by this configuration that we request you please do not modify as they will cause the Sumo Logic apps to not function correctly.

  • component: “cache” - This value is used by Sumo Logic apps to identify application components. 

  • cache_system: “varnish” - This value identifies the cache system.

For all other parameters please see this doc for more properties that can be configured in the Telegraf agent globally.

  1. (Optional) Collecting Varnish Logs from a Log File

Follow the  steps below to capture Varnish logs from a log file on Kubernetes.

  1. Install the Sumo Logic tailing sidecar operator.

  2. Add the following annotation in addition to the existing annotations.

annotations:
  tailing-sidecar: sidecarconfig;<mount>:<path_of_Varnish_log_file>/<Varnish_log_file_name>

Example:

annotations:
  tailing-sidecar: sidecarconfig;data: /var/log/varnish/varnishncsa.log
  1. Make sure that the Varnish pods are running and annotations are applied by using the command: kubectl describe pod <Varnish_pod_name>

  2. Sumo Logic Kubernetes collection will automatically start collecting logs from the pods having the annotations defined above. 

  3. Verify logs in Sumo Logic.

3. Add an FER to normalize the fields in Kubernetes environments.

Labels created in Kubernetes environments automatically are prefixed with pod_labels. To normalize these for our app to work, we need to create a Field Extraction Rule if not already created for WebServer Application Components. To do so:

  1. Go to Manage Data > Logs > Field Extraction Rules.

  2. Click the + Add button on the top right of the table.

  3. The following form appears:

  1. Enter the following options:

  • Rule Name. Enter the name as App Observability - Cache.
  • Applied At. Choose Ingest Time
  • Scope. Select Specific Data
  • Scope: Enter the following keyword search expression: 

pod_labels_environment=* pod_labels_component=cache pod_labels_cache_cluster=* pod_labels_cache_cluster=*

  • Parse Expression.Enter the following parse expression:

if (!isEmpty(pod_labels_environment), pod_labels_environment, "") as environment
| pod_labels_component as component
| pod_labels_cache_system as cache_system
| pod_labels_cache_cluster as cache_cluster

  1. Click Save to create the rule.