Adding Additional Features

A developer may want to provide additional features for their application, such as sending logs to an external endpoint.

Developers can write these features directly into an application’s container, or they can create a “sidecar” container that does some of this work.

Example with FluentBit

One common example of a sidecar feature may be to include a FluentBit container in your pod that sends log data to an Elastic Search database. This can be used for customizable metrics monitoring, or system debugging.

Workflow for including FluentBit sidecar container:

  1. Download and customize the Frontier Squid FluentBit ConfigMap for your deployment.
    • Change template name to your chart in the metadata
    • Update Input Path to your container’s log directory
    • Include the SLATE specific values in your values.yaml, found under “Preparing a Helm chart”, and set your defaults.
    • Create a custom parser using regular expressions to characterize your logs
  2. Copy the namespace helper function into your _helpers.tpl file.

    {{- define "namespace" -}}
      {{- .Release.Namespace | trimPrefix "slate-vo-" | printf " %s" -}}
    {{- end -}}
  3. Include the FluentBit container in your deployment, and mount a shared volume around the log files in your host container, and mount your ConfigMap. For example:

      - name: fluent-bit
        image: fluent/fluent-bit:0.13.4
        imagePullPolicy: IfNotPresent
        - name: {{ template "[chart].fullname" . }}-fluent-bit-config
          mountPath: /fluent-bit/etc/
        - name: varlog
          mountPath: /var/log
      - name: {{ template "[chart].fullname" . }}-fluent-bit-config
          name: {{ template "[chart].fullname" . }}-fluent-bit-config
      - name: varlog
        emptyDir: {}

    where varlog is mounted to FluentBit and to your container’s log directory.