OpenMemory Pod Silent Failure: Diagnosis & Fix

by Alex Johnson 47 views

In the realm of Kubernetes deployments, a silent failure can be one of the most insidious issues to tackle. Unlike crashes that are immediately apparent, a silent failure occurs when a container within a pod unexpectedly terminates, yet the pod itself remains in a 'Running' state due to the presence of sidecar containers. This can lead to applications behaving erratically or becoming completely unresponsive without any immediate indication of the underlying problem. This article delves into a specific instance of a silent failure observed in the openmemory pod, exploring the root causes, affected files, and actionable remediation steps. Let's get started!

Understanding the Silent Failure: openmemory-6979d5546-945ns

Alert Details

  • Alert Type: A2 (Silent Agent Failure)
  • Pod: openmemory-6979d5546-945ns
  • Namespace: cto
  • Phase: Running
  • Agent: unknown
  • Task ID: unknown

Summary

The core issue revolves around a container crash within the openmemory-6979d5546-945ns pod. What makes this particularly challenging is that the pod appeared healthy because sidecar containers were still operational, maintaining the pod's 'Running' status. This masked the underlying failure, preventing immediate detection and resolution. Further complicating matters, the affected pod has since been replaced, indicating that it belonged to a previous ReplicaSet that has been rotated out. This rotation pattern suggests a recurring problem within the OpenMemory deployment, warranting a thorough investigation.

The inability to fetch logs directly from the crashed pod (openmemory-6979d5546-945ns) due to its replacement necessitates an analysis of similar recent issues to identify common patterns and potential root causes. This proactive approach is crucial for addressing the underlying instability and preventing future silent failures.

Crash Point

The attempt to retrieve logs from the failed pod resulted in the following error:

[Failed to fetch logs: error: error from server (NotFound): pods "openmemory-6979d5546-945ns" not found in namespace "cto"]

Drawing upon the analysis of a similar recent incident (issue #2557) involving the openmemory-7f65549868-d9qkh pod, a typical crash pattern emerges. This pattern provides valuable clues regarding the potential causes of the silent failure:

[AUTH] No API key configured
[MCP] Incoming request: {"id":1,"jsonrpc":"2.0","method":"initialize","params":{"capabilities":{},"clientInfo":{"name":"tools","version":"1.0.0"},"protocolVersion":"2024-11-05"}}
[MCP] Incoming request: {"id":2,"jsonrpc":"2.0","method":"tools/list","params":{}}
[AUTH] No API key configured

This log snippet suggests potential issues related to authentication and the handling of MCP (Microservice Communication Protocol) requests. The absence of an API key configuration and the subsequent failure to process MCP requests point towards misconfigurations or unhandled exceptions within the OpenMemory service.

Decoding the Root Cause Analysis

Primary Cause: Diving into Missing Environment Configuration

The primary suspect in this silent failure mystery is a combination of missing environment configurations. The OpenMemory service seems to be stumbling due to:

  1. The Missing OM_TIER Environment Variable: The warning message [OpenMemory] OM_TIER not set! is a critical indicator. This environment variable is likely essential for the OpenMemory service to function correctly, and its absence can lead to unpredictable behavior and eventual failure.
  2. Authentication Misconfiguration: The recurring [AUTH] No API key configured warnings strongly suggest an authentication mode mismatch. The service might be expecting an API key for authentication, but either the key is not being provided or the authentication mechanism is not properly configured. This can prevent the service from accessing necessary resources or performing critical operations.

These missing environment variables and authentication issues can disrupt the normal operation of the OpenMemory service, leading to crashes and the observed silent failures. Addressing these configuration gaps is paramount to restoring stability and preventing future incidents.

Secondary Cause: Unraveling Unhandled Exceptions in the MCP Protocol Handler

Beyond the configuration issues, a secondary contributor to the silent failures appears to be unhandled exceptions within the MCP (Microservice Communication Protocol) handler. The observed pattern suggests that:

  • MCP requests are being received: The logs indicate that the service is indeed receiving MCP requests, suggesting that the communication channel itself is functional.
  • No response logs are generated: However, the absence of any corresponding response logs strongly implies that the requests are not being processed successfully.
  • Potential unhandled exception during tools/list method handling: A likely scenario is that an unhandled exception is occurring during the processing of the tools/list method. This exception could be caused by a variety of factors, such as invalid input data, unexpected errors from external dependencies, or simply a bug in the code.
  • Node.js process crashes without proper error boundaries: The fact that the Node.js process crashes without proper error boundaries further exacerbates the problem. Without proper error handling, the exception propagates up the call stack, eventually causing the entire process to terminate abruptly. This abrupt termination is what leads to the silent failure, as the container crashes without any clear indication of the root cause.

Improving error handling within the MCP request handlers is crucial for preventing these unhandled exceptions from causing the service to crash. Implementing proper error boundaries and logging mechanisms can provide valuable insights into the nature of the errors and facilitate faster debugging and resolution.

Tertiary Cause: Examining the Pod Rotation Pattern

A tertiary factor contributing to the complexity of this issue is the observed pod rotation pattern. The analysis reveals that:

  • Pod name indicates ReplicaSet openmemory-6979d5546: The pod name suggests that it belongs to a specific ReplicaSet, namely openmemory-6979d5546. ReplicaSets are Kubernetes controllers that ensure a specified number of pod replicas are running at any given time.
  • Different from current openmemory-7f65549868: The fact that this ReplicaSet is different from the current one (openmemory-7f65549868) indicates that a deployment rollout has occurred.
  • Deployment rollouts are occurring, possibly due to failed health checks: This suggests that the OpenMemory deployment is undergoing frequent rollouts, possibly triggered by failed health checks. Health checks are used by Kubernetes to monitor the health and readiness of pods. If a pod fails a health check, it is considered unhealthy and may be automatically restarted or replaced.
  • The Recreate deployment strategy combined with liveness probe failures could cause pod churn: The combination of the Recreate deployment strategy and liveness probe failures can lead to a phenomenon known as pod churn. The Recreate strategy terminates all existing pods before creating new ones. If liveness probes are too aggressive, they may prematurely mark pods as unhealthy, triggering unnecessary restarts and rollouts. This constant churn can mask underlying issues and make it more difficult to diagnose the root cause of the silent failures.

Carefully reviewing and adjusting the health check configuration and deployment strategy can help to reduce pod churn and improve the overall stability of the OpenMemory deployment.

Pinpointing the Affected Files

To effectively address the silent failure, it's crucial to identify the specific files that require modification or review. These files span across Helm chart configurations, application code, and Kubernetes resources.

Helm Chart Configuration

  • infra/charts/openmemory/values.yaml - This file is the central hub for configuring environment variables and other deployment parameters. It's essential to ensure that all required environment variables are correctly defined and that their values are appropriate for the target environment.
  • infra/charts/openmemory/templates/deployment.yaml - This file defines the deployment specification for the OpenMemory service. It specifies the number of replicas, resource limits, and other deployment-related settings. Reviewing this file can help identify potential issues with resource allocation or deployment strategies.
  • infra/charts/openmemory/templates/configmap.yaml - This file defines the ConfigMap used to store environment variables and other configuration data. Ensuring that all required environment variables are included in the ConfigMap is crucial for the proper functioning of the OpenMemory service.

Application Code (upstream openmemory repo)

  • MCP server request handlers - The code responsible for handling MCP requests needs to be thoroughly reviewed for potential error handling gaps. Implementing robust error handling mechanisms can prevent unhandled exceptions from causing the service to crash.
  • Authentication middleware - The authentication middleware should be designed to gracefully degrade when an API key is not available. This can prevent authentication failures from disrupting the normal operation of the service.

Kubernetes Resources

  • Liveness/readiness probe configuration may be too aggressive - The liveness and readiness probes should be carefully configured to accurately reflect the health and readiness of the OpenMemory service. Avoid overly aggressive probes that can lead to unnecessary restarts and rollouts.
  • Resource limits may need adjustment for stability - The resource limits for the OpenMemory service should be carefully tuned to ensure that the service has sufficient resources to operate stably. Insufficient resources can lead to performance degradation and even crashes.

Charting a Course for Remediation

To effectively address the silent failure and prevent future occurrences, a multi-pronged approach is required. This involves adding missing environment variables, improving error handling in OpenMemory, adjusting health check configurations, and reviewing resource limits.

  1. Add Missing Environment Variables
    • Add OM_TIER=hybrid to the ConfigMap or deployment env vars
    • Verify all required environment variables are set in values.yaml
  2. Improve Error Handling in OpenMemory
    • Add global try-catch for MCP request handlers
    • Implement graceful error responses instead of process crash
    • Add uncaughtException/unhandledRejection handlers
  3. Adjust Health Check Configuration
    • Increase initialDelaySeconds on liveness probe to allow startup time
    • Add more retries before marking unhealthy
    • Consider adding a separate endpoint for deep health vs shallow health
  4. Review Resource Limits
    • Current: CPU 2000m/500m, Memory 4Gi/1Gi
    • Verify these are sufficient for embedding model loading
    • Check for OOM events in cluster metrics
  5. Test Locally with Docker
    docker pull ghcr.io/5dlabs/openmemory:latest
docker run --rm -e OM_TIER=hybrid -p 8080:8080 ghcr.io/5dlabs/openmemory:latest
  6. Verify Fix in Staging
    • Deploy configuration changes
    • Monitor for 24 hours for silent failures
    • Check Heal system for no new A2 alerts

Defining Acceptance Criteria - Issue #2586

To ensure that the remediation efforts are successful, it's essential to define clear acceptance criteria. These criteria should cover code fixes, deployment procedures, and verification steps.

Definition of Done

Code Fix

  • [ ] Root cause of silent failure identified
  • [ ] Fix implemented to prevent crash/unhandled error
  • [ ] Error handling improved if applicable
  • [ ] Code passes cargo fmt --all --check
  • [ ] Code passes cargo clippy --all-targets -- -D warnings
  • [ ] All tests pass: cargo test --workspace

Deployment

  • [ ] PR created and linked to issue #2586
  • [ ] CI checks pass
  • [ ] PR merged to main
  • [ ] ArgoCD sync successful

Verification

  • [ ] Agent completes successfully with exit code 0
  • [ ] No silent failures in subsequent runs
  • [ ] Heal monitoring shows no new A2 alerts for similar failures

By adhering to these acceptance criteria, we can confidently verify that the silent failure has been effectively addressed and that the OpenMemory deployment is operating stably.

To enhance your understanding of Kubernetes deployments and troubleshooting, consider exploring resources like the official Kubernetes Documentation.