Reference Application for workload monitoring

Unsupported and removed in 2.28.3 (16.3.3) Available since 2.21.0 (11.5.0) for non-MOSK managed clusters

Note

For the feature support on MOSK deployments, refer to MOSK documentation: Deploy your first cloud application using automation.

Reference Application is a small microservice application that enables workload monitoring on non-MOSK managed clusters. It mimics a classical microservice application and provides metrics that describe the likely behavior of user workloads.

The application consists of the following API and database services that allow putting simple records into the database through the API and retrieving them:

Reference Application API

Runs on StackLight nodes and provides API access to the database. Runs three API instances for high availability.

PostgreSQL Since Container Cloud 2.22.0

Runs on worker nodes and stores the data on an attached PersistentVolumeClaim (PVC). Runs three database instances for high availability.

Note

Before version 2.22.0, Container Cloud used MariaDB as the database management system instead of PostgreSQL.

StackLight queries the API measuring response times for each query. No caching is being done, so each API request must go to the database, allowing to verify the availability of a stateful workload on the cluster.

Reference Application requires the following resources on top of the main product requirements:

  • Up to 1 GiB of RAM per cluster

  • Up to 3 GiB of storage per cluster

The feature is disabled by default and can be enabled using the StackLight configuration manifest and the following parameters:

Key

Description

Example values

refapp.enabled (bool)

Enables or disables Reference Application that is a small microservice application that enables workload monitoring on non-MOSK managed clusters. Disabled by default.

true or false

refapp.workload.persistentVolumeEnabled (bool)
Available since Container Cloud 2.23.0.
Enables or disables persistent volumes for Reference Application. Enabled by default. Disabling is not recommended for production clusters. Once set, the value cannot be changed.

true or false

refapp.workload.storageClassName (string)

Defines StorageClass to use for Reference Application persistent volumes. Empty by default. If empty, uses the default storage class. Once set, the value cannot be changed. Takes effect only if persistent volumes are enabled.

 
refapp:
  workload:
    storageClassName: kubernetes-ssd

refapp.workload.persistentVolumeSize (string)
Available since Container Cloud 2.23.0.
Defines the size of persistent volumes for the Reference Application. Default is 1Gi. Applies only if persistent volumes are enabled.
 
refapp:
  workload:
    persistentVolumeSize: 1Gi