K8s MCP Server

K8s MCP Server

Enhanced Kubernetes access with AI-friendly port-forward management supporting headless services.

✅ Implementation Complete - All core features have been implemented.

Features

• kubectl-Inspired Output Formats: Multiple output formats (table, wide, json, yaml, custom-columns, jsonpath) for efficient token usage
• Resource Kind Discovery: Natural language queries to find Custom Resource Definitions and builtin resources by keywords
• URL-based Configuration: Share port-forward configs via GitHub Gists or local files
• Headless Service Support: Direct pod targeting via label selectors
• AI-Optimized: Clean service/target structure for intelligent fuzzy matching
• Multi-format Support: YAML, JSON, TOML configuration files
• kubectl-like Behavior: Selects first ready pod, same as kubectl port-forward
• Session Management: In-memory port-forward tracking with list and teardown capabilities
• Parameterless Discovery: Easy cluster, alias, and service discovery for AI agents

Quick Start

1. Install Dependencies

pip install -e .

2. Set Environment Variables

# Required: Kubernetes cluster configurations
export KUBECONFIG_URLS="dev=file:///path/to/dev.yaml prod=file:///path/to/prod.yaml"

# Optional: Cluster aliases
export KUBECONFIG_ALIASES="development=dev production=prod"

# Required: Port-forward configuration URL
export PORT_FORWARD_CONFIG_URL="file://$(pwd)/example-port-forward-config.yaml"
# Or use a GitHub Gist:
# export PORT_FORWARD_CONFIG_URL="https://gist.githubusercontent.com/user/abc123/raw/port-forward.yaml"

3. Run the Server

python main.py

Usage Examples

AI Agent Interactions

User: "Setup port-forward to the FRET Druid in development"
AI Agent:
1. Calls discover_port_forward_services() to understand available services
2. Maps "FRET Druid in development" → service="druid", target="fret-dev"  
3. Calls setup_port_forward_to_target("druid", "fret-dev")
4. Returns: "✅ Connected to fret-dev Druid: http://localhost:8082 → pod/druid-router-0"

Direct Tool Calls

• connect_to_service_targets("druid", ["fret-dev"]) - Connect to specific target
• connect_to_service_targets("druid", []) - Connect to all Druid environments
• list_resources("prod", "pods", labels={"app": "nginx"}) - List pods with labels
• get_resource("dev", "deployment", "my-app", "default") - Get specific resource
• discover_resource_kinds("dev", ["druid", "ingestion"]) - Find resource kinds by keywords
• list_resources("dev", "pods", output_format="custom-columns", custom_columns="NAME:.metadata.name,IP:.status.podIP") - Custom output
• list_port_forwards() - Show active port-forward sessions
• teardown_port_forward("forward-id") - Stop a port-forward session
• Supports kubectl naming variants: "pods", "pod", "po" all work

Output Format Examples

Token-Efficient Resource Listing

# Default table format (kubectl-like)
list_resources(cluster="dev", kind="pods", namespace="fret-dev")
# Returns clean table: NAME | READY | STATUS | RESTARTS | AGE

Custom Columns for Specific Data

# Extract specific fields with JSONPath
list_resources(
    cluster="dev", 
    kind="services",
    output_format="custom-columns", 
    custom_columns="NAME:.metadata.name,TYPE:.spec.type,PORTS:.spec.ports[*].port"
)

Resource Kind Discovery

# Find resource kinds by keywords
discover_resource_kinds(
    cluster="dev",
    keywords=["druid", "ingestion"],
    match_mode="OR"
)
# Returns: DruidIngestion resource kind info with all naming variants

Resource Naming Conventions

The K8s MCP server follows kubectl naming conventions:

Resource Kind Support

• Plural forms: pods, services, deployments
• Singular forms: pod, service, deployment
• Abbreviations: po, svc, deploy, sts (for StatefulSet)
• Case insensitive: Pod, POD, pod all work

Discovery vs Search

• discover_* tools find available resource kinds/types
• search_* and list_* tools find specific instances

Example Workflow

# 1. Discover what kinds are available
discover_resource_kinds(cluster="dev", keywords=["druid"])
# Returns: DruidIngestion kind with variants ["druidingestions", "druidingestion"]

# 2. List instances using any variant
list_resources(cluster="dev", kind="druidingestions")
# or
list_resources(cluster="dev", kind="DruidIngestion")

Configuration

Port-Forward Config Format

druid:
  fret-dev:
    k8s_cluster: "dev-us-east"
    namespace: "druid"
    labels:
      app.kubernetes.io/component: "router"
    local_port: 8082
    remote_port: 8888

grafana:
  dev:
    k8s_cluster: "dev-us-east"
    namespace: "monitoring"
    labels:
      app.kubernetes.io/name: "grafana"
    local_port: 3000
    remote_port: 3000

Common Workflows

These workflow examples demonstrate how AI agents can combine multiple tools to accomplish complex Kubernetes tasks:

1. Cluster Overview Workflow

User: "Show me the status of all my clusters"
AI Agent Flow:
1. discover_clusters() → Get available clusters ["dev", "staging", "prod"]
2. For each cluster:
   - cluster_health() → Check API server connectivity
   - list_resources("cluster", "nodes") → Get node count and status
   - list_resources("cluster", "namespaces") → Get namespace overview
3. Summarize: "3 clusters online, 12 total nodes, 8 namespaces"

2. Application Debugging Workflow

User: "My app isn't working in staging"
AI Agent Flow:
1. list_resources("staging", "pods", labels={"app": "user-app"}) → Find app pods
2. For each pod:
   - describe_resource("staging", "pod", pod_name) → Get detailed status
   - get_logs("staging", pod_name, lines=50) → Check recent logs
   - list_resources("staging", "events", field_selector=f"involvedObject.name={pod_name}") → Get events
3. Analyze patterns: "Found 2 pods crash-looping due to missing config map 'app-config'"

3. Safe Deployment Update Workflow

User: "Update nginx deployment to version 1.21"
AI Agent Flow:
1. get_resource("prod", "deployment", "nginx") → Get current deployment
2. Modify image version in manifest
3. Present proposed changes: "Will update image from nginx:1.20 to nginx:1.21"
4. User confirms: "Apply it"
5. update_resource("prod", "deployment", "nginx", new_manifest) → Apply update
6. Monitor rollout status with deployment_status()

4. Resource Cleanup Workflow

User: "Clean up all test resources from last week"
AI Agent Flow:
1. list_resources("dev", "all", labels={"purpose": "test", "created": "2024-01-15"}) → Find test resources
2. Group by type: "Found 5 pods, 3 services, 2 configmaps"
3. For each resource:
   - Show resource details and age
4. Present deletion plan with resource details
5. User confirms: "Yes, delete them"
6. Execute deletions with proper cascade handling

5. Enhanced Port-Forward Workflow

User: "Setup port-forward to the FRET Druid in development"
AI Agent Flow:
1. discover_port_forward_services() → Get available services/targets
2. AI reasoning: "FRET Druid in development" → service="druid", target="fret-dev"
3. connect_to_service_targets("druid", ["fret-dev"]) → Setup to specific target
4. Return: "✅ Connected to fret-dev Druid: http://localhost:8082 → pod/druid-router-0"

6. Troubleshooting Performance Workflow

User: "Why is my app slow in production?"
AI Agent Flow:
1. list_resources("prod", "pods", labels={"app": "slow-app"}) → Find app pods
2. For each pod:
   - describe_resource() → Check resource limits/requests
   - get_logs(since="1h") → Check for performance-related logs
   - execute_in_pod(["top", "-b", "-n", "1"]) → Get resource usage
3. list_resources("prod", "nodes") → Check node capacity
4. query_by_labels("prod", "hpa", "app=slow-app") → Check auto-scaling
5. Analyze: "App is CPU-throttled, increase CPU requests from 100m to 250m"

7. Security Audit Workflow

User: "Audit RBAC permissions for the finance team"
AI Agent Flow:
1. list_resources("prod", "rolebindings") → Get all role bindings
2. list_resources("prod", "clusterrolebindings") → Get cluster-wide bindings
3. Filter by subjects containing "finance"
4. For each binding:
   - get_resource("prod", "role", role_name) → Get role permissions
5. Summarize: "Finance team has read access to secrets in finance namespace"

8. Disaster Recovery Workflow

User: "Restore the database from backup"
AI Agent Flow:
1. list_resources("prod", "pods", labels={"app": "database"}) → Find DB pods
2. scale_resource("prod", "deployment", "database", replicas=0) → Scale down
3. Wait for pods to terminate
4. apply_manifest("prod", restore_job_manifest) → Apply restore job
5. Monitor job status until completion
6. scale_resource("prod", "deployment", "database", replicas=1) → Scale back up
7. Verify database connectivity

Best Practices for AI Agents

1. Always Preview Changes: Use diff/dry-run before modifications
2. Provide Context: Include relevant information when reporting issues
3. Batch Operations: Group related operations for efficiency
4. Handle Pagination: Be aware of large result sets
5. Respect Cluster Boundaries: Never assume operations across clusters

Tool Safety Classifications

All MCP tools are classified by their safety level for AI agent operations:

[READ-ONLY] Tools - Safe for autonomous use

These tools only read data and never modify cluster or local state:

Resource Operations:

• get_resource() - Get specific resource details
• get_resource_yaml() - Get resource as YAML
• list_resources() - List resources with formatting options
• list_resources_yaml() - List resources as YAML
• query_by_labels() - Advanced label-based queries
• query_by_labels_yaml() - Label queries as YAML

Monitoring & Analysis:

• troubleshoot_pod() - Comprehensive pod debugging
• troubleshoot_pod_yaml() - Pod debugging as YAML
• cluster_health() - Overall cluster health assessment
• deployment_status() - Deployment rollout analysis
• deployment_status_yaml() - Deployment analysis as YAML
• resource_usage() - Resource consumption analysis
• get_logs() - Retrieve pod logs
• list_port_forwards() - List active port-forward sessions

Discovery:

• discover_resource_kinds() - Find resource types by keywords
• discover_clusters() - List available clusters
• discover_cluster_aliases() - List cluster aliases
• discover_port_forward_services() - List port-forward configurations

[MODIFIES STATE] Tools - Require user approval

These tools modify cluster state or local network configuration:

Resource Management:

• create_resource() - Create new Kubernetes resources
• update_resource() - Update existing resources
• patch_resource() - Partially update resources
• scale_resource() - Change replica counts
• apply_manifest() - Apply YAML manifests

Network Operations:

• connect_to_service_targets() - Connect to configured service environments
• setup_port_forward() - Generic port-forward setup
• teardown_port_forward() - Close port-forward sessions

[DANGEROUS] Tools - Require explicit user confirmation

These tools can cause data loss or security risks:

• delete_resource() - Permanently delete resources (cannot be undone)
• execute_in_pod() - Run arbitrary commands in pods (potential security risk)

AI Agent Safety Guidelines

1. Autonomous Operations: AI agents can freely use [READ-ONLY] tools
2. State Changes: [MODIFIES STATE] tools should require user approval
3. High-Risk Operations: [DANGEROUS] tools must have explicit user confirmation
4. Error Handling: All tools return consistent error formats for safe parsing

Architecture

k8s-mcp/
├── main.py                 # MCP server entry point with tool definitions
├── config/                 # Configuration management  
│   ├── loader.py          # URL-based config loading
│   ├── manager.py         # Cluster and port-forward session management
│   └── config.py          # Environment validation and configuration
├── tools/                  # Modular tool implementations
│   ├── resources.py       # Common resource operation patterns
│   ├── formatting.py      # All resource formatting (table, YAML, JSON)
│   ├── columns.py         # Default column definitions for resources
│   ├── discovery.py       # Resource kind discovery and CRD enumeration
│   └── port_forward.py    # Port-forward specific operations
└── utils/                  # Shared utilities
    ├── helpers.py         # Common helper functions
    └── jsonpath.py        # JSONPath processing for custom columns

Code Organization Principles

• Single Responsibility: Each module has a clear, focused purpose
• DRY Compliance: No duplicate implementations across files
• Separation of Concerns: Client management, formatting, and business logic are separated
• Modular Design: Tools can be imported and reused independently