Track Costs with OpenCost

Objectives

This tutorial introduces OpenCost, the cost monitoring and optimization tool integrated into your Managed Kubernetes cluster. By the end of this guide, you will be able to:

• Access the OpenCost interface.
• Understand the interface structure and available views.
• Analyze the cost distribution of your applications and infrastructure.

What is OpenCost?

OpenCost is an open-source, CNCF (Cloud Native Computing Foundation) standard solution that provides real-time visibility into the costs of your Kubernetes environments. It helps you precisely understand what is consuming resources within your cluster and how this translates into cost.

In the Managed Kubernetes offering, OpenCost is pre-installed and pre-configured to give you a clear view of your expenses. It is directly configured with the actual infrastructure costs from Temple Cloud.

Access the OpenCost Interface

The OpenCost interface is exposed on a secure URL specific to your cluster. To access it, use the following URL, replacing identifiant with your cluster's identifier (for example, ctodev):

https://opencost.external-secured.identifiant.mk.ms-cloud-temple.com

info

Access to this URL is restricted to the IP addresses you have declared with Cloud Temple support. If you are unable to access it, please contact support to verify your firewall rules.

Explore Cost Allocation

The main and most detailed view in OpenCost is the Allocations dashboard. This is where you can visualize your resource consumption in real time.

This view allows you to break down costs by native Kubernetes concepts. The "Aggregate by" dropdown is your primary analytical tool, enabling you to group costs by:

• Namespace: To get a view by environment or team.
• Deployment, StatefulSet, etc.: To analyze the cost of a specific application.
• Controller: For a more technical perspective.

Cost Aggregation by Labels

For even more granular financial analysis, OpenCost can aggregate costs based on Kubernetes labels. There isn't a direct "Label" option in the menu, but OpenCost ingests your labels and enables you to create custom aggregations. For this, a consistent labeling strategy is essential. For example, using labels such as team: backend or product: api-gateway allows you to analyze costs precisely aligned with your organizational structure.
For this type of analysis, you must use OpenCost's AI integration.

Grafana Dashboard

A Grafana dashboard is also available to visualize OpenCost data. This dashboard provides an alternative and complementary view to the OpenCost interface, and it retains the complete history of cost metrics, enabling you to analyze long-term trends.

Advanced Usage: Integration with an AI (MCP Server)

For advanced users, OpenCost can be directly queried from the Cline conversational assistant (or others) through the MCP (Multi-purpose Co-processor) servers system. This enables you to script queries and retrieve cost data directly within your conversations.

1. Configuring OpenCost MCP in Cline

To connect Cline to your OpenCost instance, add the following configuration to your cline_mcp_settings.json file. This file is typically located in the Cline configuration directory.

We recommend creating an MCP server named "opencost-xxxxx", where xxxxx is the name of your managed Kubernetes cluster.
The MCP server URL is in the format: https://opencost-mcp.external-secured.identifiant.mk.ms-cloud-temple.com

For example, for the cluster "bestie":

{
  "mcpServers": {
    "opencost-bestie": {
      "disabled": false,
      "timeout": 60,
      "type": "streamableHttp",
      "url": "https://opencost-mcp.external-secured.bestie.mk.ms-cloud-temple.com",
      "headers": {
        "Authorization": "Basic <TOKEN>"
      }
    }
  }
}

To generate the <TOKEN> value from your credentials, use one of the following commands:

For Linux/macOS:

echo -n 'finopsadm:VOTRE_MOT_DE_PASSE' | base64

For Windows (PowerShell):

$credentials = [System.Text.Encoding]::UTF8.GetBytes("finopsadm:VOTRE_MOT_DE_PASSE")
[System.Convert]::ToBase64String($credentials)

Once this file is saved, Cline will automatically load the opencost-xxxxx MCP at startup.

2. Query OpenCost with MCP

Prerequisites

To interact with MCP using natural language, the underlying AI must have access to language models (LLMs), either locally (e.g., LMStudio) or via connections to public services such as GPT-5 or Gemini, or by using our sovereign LLM-as-a-Service offering.

After setup, you can use LLM tools to perform natural language queries against this MCP server.

Example:

"Use the MCP 'opencost-bestie', and tell me what percentage of the cluster's costs are not allocated to resources" You will get this:

Example 2:

"Use the MCP 'opencost-bestie', and list me the costs associated with persistent volumes for yesterday"

Example 3:

"Use the OpenCost MCP opencost-bestie, and tell me what percentage of the cluster costs are allocated to the application with the label 'nginx' (filter of the form filter: 'label:app:frontend')."

Conclusion

OpenCost provides you with powerful tools for fine-grained, real-time analysis of your Kubernetes cluster costs. By primarily using the Allocations view and combining it with a solid labeling strategy, you can gain a clear understanding of your spending, aligned both with your technical deployments and internal organizational structure. Leveraging LLMs and the OpenCost MCP server enables you to take data exploitation even further.