pods-graph

Relationship between the Kubernetes pods and their volumes

What does this application do, in more detail?

This application provides a detailed and interactive way to visualize Kubernetes resources and their relationships within a cluster. Here’s a more in-depth explanation of what the application does:

1. Kubernetes Cluster Interaction: The application connects to your Kubernetes cluster using a specified kubeconfig file.

2. Resource Retrieval: The application fetches four main types of Kubernetes resources:

   • Pods: The smallest deployable units that can be created and managed in Kubernetes, usually running one or more containers.

   • Persistent Volume Claims (PVCs): Requests for storage by users. PVCs abstract the storage resource requirements of applications.

   • Persistent Volumes (PVs): Actual storage resources in the cluster that can be used by PVCs.

   • Volumes: Provides detailed insights into Persistent Volumes by tracking their capacities and statuses.

3. Namespace Specification: Users can specify which namespaces to pull resources from. If no namespace is specified, the application fetches resources from all namespaces in the cluster, providing a comprehensive view.

4. Graph Creation:

   • The application constructs a directed graph using networkx, a Python package for creating and manipulating complex networks.

   • Nodes in the graph represent the resources (Pods, PVCs, PVs, and Volumes). Each node is labeled with detailed information, including the resource’s name, status, capacity, and type.

   • Edges between nodes represent relationships: for example, how Pods use PVCs, and how PVCs are bound to PVs. The edges are labeled to indicate the nature of these connections.

5. Resource Status and Capacity Visualization:

   • The graph provides a visual overview of each resource’s status, such as whether a Pod is running, pending, or failed, or whether a PVC is bound or unbound.

   • It also shows the capacity of storage resources, giving users insights into how much storage each PVC and PV is requesting or providing.

6. Namespace and Pattern Filtering:

   • Users can specify pod name patterns using wildcards to filter Pods more precisely. This feature enhances the granularity of resource visualization.

   • The application can handle both namespace-specific and global resource queries, providing flexibility in fetching data.

7. Error Handling: The application includes robust error handling to deal with issues such as failed connections, missing resources, or permission errors, and outputs helpful error messages to guide users in troubleshooting.

8. Graph Visualization:

   • The graph is rendered using matplotlib, a plotting library that displays the graph directly in a visual format.

   • This visual representation makes it easy for users to understand complex resource dependencies and quickly identify potential issues such as unbound volumes or Pods without storage.

What are the possible use cases?

1. Troubleshooting: Quickly identify Pods that are not running as expected, PVCs that are not correctly bound to PVs, or Volumes that are not properly utilized.

2. Resource Management: Gain a clear overview of how storage resources are allocated and used across different namespaces, and monitor the status and capacity of Persistent Volumes.

3. Cluster Monitoring: Continuously monitor the health and status of Kubernetes resources in a visual format that is easier to digest than raw command-line outputs.

4. Detailed Analysis: Use pod name patterns to filter and analyze specific Pods, allowing for more targeted troubleshooting and resource management.

Overall, this application simplifies the management of Kubernetes resources by transforming abstract connections into a visual map. This allows DevOps engineers, SREs, and Kubernetes administrators to quickly grasp the state of their clusters, identify potential issues, and optimize resource utilization.

Requirements:

python3 -m venv venv
source venv/bin/activate
pip3 install kubernetes networkx matplotlib
#`deactivate`is the command to use to exit the venv environment.

How to use the script:

$ python3 graph.py -h
usage: graph.py [-h] [-k KUBECONFIG] [-n [NAMESPACES ...]] [-p [PODS ...]]

Generate a graph of Kubernetes resources such as Pods, Persistent Volume Claims (PVCs), and Persistent Volumes (PVs). Fetches resources from specified
Kubernetes namespaces and visually represents their relationships.

options:
  -h, --help            show this help message and exit
  -k KUBECONFIG, --kubeconfig KUBECONFIG
                        Path to the kubeconfig file (default: ~/.kube/config).
  -n [NAMESPACES ...], --namespaces [NAMESPACES ...]
                        Kubernetes namespace(s) to use. If not specified, fetches resources from all namespaces.
  -p [PODS ...], --pods [PODS ...]
                        Pod name patterns to filter. Use wildcard patterns as needed.

Example usage: python graph.py -k ~/.kube/config -n default -p pod-name-1-hash pod-name-2-*