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Sumo Logic

Collect Elasticsearch Logs and Metrics for Kubernetes environments

This page assists to collect 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 Elasticsearch in a Kubernetes environment. Four services in the architecture shown below make up the metric collection pipeline: Telegraf, Prometheus, Fluentd, and FluentBit.

The first service in the pipeline is Telegraf. Telegraf collects metrics from Elasticsearch. 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 Elasticsearch 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.

 

Follow the below instructions to set up the logs and  metric collection:

  1. Configure Metrics Collection

    1. Setup Kubernetes Collection with the Telegraf operator
    2. Add annotations on your Elasticsearch pods
  2. Configure Logs Collection

    1. Configure logging in Elasticsearch.
    2. Add labels on your Elasticsearch pods to capture logs from standard output.
    3. Collecting Elasticsearch Logs from a Log file.

Step 1 Configure Metrics Collection

This section explains the steps to collect Elasticsearch 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 about this here. Follow the steps listed below to collect metrics from a Kubernetes environment:

  1. Set up Kubernetes Collection with the Telegraf Operator.

  2. Add annotations on your Elasticsearch pods
    On your Elasticsearch Pods, add the following annotations:

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

  • telegraf.influxdata.com/inputs - This contains the required configuration for the Telegraf Elasticsearch Input plugin. Please refer to this doc for more information on configuring the Elasticsearch input plugin for Telegraf. Note: As telegraf will be run as a sidecar the host should always be localhost.
  • In the input plugins section i.e. [[inputs.elasticsearch]]: 
    • servers - The URL to the Elasticsearch server. This can be a comma-separated list to connect to multiple Elasticsearch servers. Please see this doc for more information on additional parameters for configuring the Elasticsearch input plugin for Telegraf.
  • In the tags section i.e.  [inputs.elasticsearch]
    • environment - This is the deployment environment where the Elasticsearch cluster identified by the value of servers resides. For example dev, prod, or QA. While this value is optional we highly recommend setting it. 
    • db_cluster - Enter a name to identify this Elasticsearch 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.elasticsearch.tags]
      • component: “database” - This value is used by Sumo Logic apps to identify application components. 
      • db_system: “elasticsearch” - This value identifies the database 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 Elasticsearch logs from a Kubernetes environment.

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

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

  1. Apply the following labels to the Elasticsearch pods:

     labels:
        environment: "dev_CHANGE_ME>"
        component: "database"
        db_system: "elasticsearch"
        db_cluster: "elasticsearch_on_k8s_CHANGE_ME>”

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

  • environment - This is the deployment environment where the Elasticsearch cluster identified by the value of servers resides. For example dev, prod, or QA. While this value is optional we highly recommend setting it.
  • db_cluster - Enter a name to identify this Elasticsearch 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: “database” - This value is used by Sumo Logic apps to identify application components. 
  • db_system: “elasticsearch” - This value identifies the database system.

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

  1. The Sumologic-Kubernetes-Collection will automatically capture the logs from stdout and will send the logs to Sumologic. For more information on deploying Sumologic-Kubernetes-Collection, visit here.

  2. Verify logs in Sumo Logic.

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

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

  1. Determine the location of the Elasticsearch log file on Kubernetes. This can be determined from the log4j.properties for your Elasticsearch cluster along with the mounts on the Elasticsearch pods.
  2. Install the Sumo Logic tailing sidecar operator.
  3. Add the following annotation in addition to the existing annotations.
annotations:
  tailing-sidecar: sidecarconfig;<mount>:<path_of_Elasticsearch_log_file>/<Elasticsearch_log_file_name>

Example:

annotations:
  tailing-sidecar: sidecarconfig;data:/usr/share/elasticsearch/logs/gc.log
  1. Make sure that the Elasticsearch pods are running and annotations are applied by using the command: kubectl describe pod <Elasticsearch_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 a 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 Database 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 - Database.
  • Applied At. Choose Ingest Time
  • Scope. Select Specific Data
  • Scope: Enter the following keyword search expression: pod_labels_environment=* pod_labels_component=database pod_labels_db_system=* pod_labels_db_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_db_system as db_system
    | pod_labels_db_cluster as db_cluster
  1. Click Save to create the rule.