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The Software's Journey profile image Willem van Heemstra
Willem van Heemstra for The Software's Journey

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Finding Crossplane's Black Box: A Flight Data Recorder for Your Infrastructure

#crossplane #kubernetes #infrastructure #devops

Welcome back, fellow Infrastructure Aviators! 🛩️

In our previous adventures, we've learned to navigate the skies of Infrastructure-as-Code with Crossplane. But what happens when your infrastructure takes an unexpected nosedive? When your Compositions crash and burn? When your Managed Resources refuse to take off?

That's when you need to find the black box.

The Mystery of the Missing Logs

Picture this: You're a crash investigator for infrastructure incidents. Your AWS S3 bucket didn't provision. Your Azure Virtual Network is stuck in "Pending" purgatory. Your GCP compute instance has gone AWOL. The only clues? Somewhere in the wreckage lies Crossplane's flight data recorder—its logs.

Unlike aviation's orange boxes (yes, "black boxes" are actually bright orange—aviation's little joke on us), Crossplane's logs are scattered across multiple locations, each telling a different part of the story. Think of it as a distributed cockpit voice recorder, capturing every muttered complaint from your infrastructure components.

Pre-Flight Checklist: What You'll Need

Before we start excavating through log files, let's make sure you're equipped:

  • A running Kubernetes cluster (hopefully not on fire)
  • Crossplane installed (preferably still breathing)
  • kubectl access (your investigator's toolkit)
  • Coffee ☕ (the universal debugging fuel)
  • Patience (a virtue, especially in infrastructure)

The Three Black Boxes of Crossplane

Box #1: The Core Controller Logs

This is your main flight data recorder. The Crossplane core controller logs everything happening at 30,000 feet—the high-level orchestration decisions.

# The primary crash site
kubectl logs -n crossplane-system deployment/crossplane -f
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What you'll find here:

  • Reconciliation loops (the heartbeat of Crossplane)
  • Composition selections and patches
  • Provider installation dramas
  • The occasional existential crisis about RBAC permissions

Pro tip: Add --previous to check what happened before the controller crashed and restarted. Because sometimes the crime scene gets cleaned up before you arrive.

kubectl logs -n crossplane-system deployment/crossplane --previous
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Box #2: Provider Logs (The Specialist Crew)

Providers are like your specialist crew members—the ones who actually turn the yoke and push the buttons. Each provider (AWS, Azure, GCP, etc.) maintains its own black box.

# Find your provider pods first
kubectl get pods -n crossplane-system

# Then check their individual stories
kubectl logs -n crossplane-system <provider-pod-name> -f
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For example, examining the AWS provider's confession:

kubectl logs -n crossplane-system \
  $(kubectl get pods -n crossplane-system -l pkg.crossplane.io/provider=provider-aws -o name | head -n 1) -f
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What you'll discover:

  • API calls to cloud providers (the actual button-pushing)
  • Authentication failures (wrong keys, expired tokens, identity crises)
  • Rate limiting incidents (when you pressed the button too enthusiastically)
  • The real reason your S3 bucket name was already taken

Box #3: Resource Events (The Air Traffic Control Transcript)

While not technically logs, Kubernetes events are like the air traffic control transcript—timestamped communications about your resources' journey.

# Check the tower communications for a specific resource
kubectl describe managed <resource-name>

# Or get events for everything in a namespace
kubectl get events -n crossplane-system --sort-by='.lastTimestamp'
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The gossip you'll overhear:

  • "Waiting for dependencies" (the infrastructure equivalent of circling the runway)
  • "External resource is up-to-date" (smooth sailing)
  • "Cannot resolve resource references" (lost the navigation chart)
  • "Provider credentials not found" (forgot the keys to the plane)

Crash Investigation Techniques

The Grep Parachute

When your logs are scrolling faster than you can read, grep is your emergency parachute:

# Find all errors (spoiler: there are always errors)
kubectl logs -n crossplane-system deployment/crossplane | grep -i error

# Track a specific resource's journey
kubectl logs -n crossplane-system deployment/crossplane | grep "my-database"

# Watch for reconciliation events
kubectl logs -n crossplane-system deployment/crossplane -f | grep "reconcile"
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The Stern Approach (Multi-Pod Tailing)

When you need to watch multiple black boxes simultaneously, stern is your co-pilot:

# Install stern first (if you haven't)
# brew install stern  # macOS
# or follow: https://github.com/stern/stern

# Watch ALL Crossplane-related logs
stern -n crossplane-system .

# Filter for specific providers
stern -n crossplane-system provider-aws

# Grep across all pods
stern -n crossplane-system . | grep "error"
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It's like having x-ray vision for your entire Crossplane deployment.

The Verbosity Dial

Crossplane controllers support log level adjustments. Sometimes you need to turn up the volume on your black box:

# Edit the Crossplane deployment
kubectl edit deployment crossplane -n crossplane-system

# Add or modify the args section:
spec:
  template:
    spec:
      containers:
      - args:
        - --debug  # Maximum verbosity
        # or
        - --verbose  # Medium verbosity
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Warning: Debug mode is like turning on the cockpit voice recorder during a family argument—you'll hear EVERYTHING. Use sparingly in production, or your log storage will file a noise complaint.

Real-World Crash Scenarios

Case Study 1: The Silent Failure

Symptom: Your XRD creates a claim, but nothing happens. No resources appear.

Investigation:

kubectl logs -n crossplane-system deployment/crossplane | grep "cannot compose"
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Black Box Reveals:

cannot compose resources: cannot render composed resource from resource template at index 0: 
cannot use dry-run create to name composed resource: 
S3Bucket.s3.aws.crossplane.io "my-bucket-123" is forbidden: 
User "system:serviceaccount:crossplane-system:crossplane" cannot create resource "s3buckets"
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Translation: "Houston, we have a permissions problem." The controller is trying to create resources but doesn't have RBAC clearance.

Fix: Update your RBAC, give Crossplane the keys to the aircraft.

Case Study 2: The Infinite Loop

Symptom: Resources keep recreating. Your infrastructure is stuck in Groundhog Day.

Investigation:

kubectl logs -n crossplane-system deployment/crossplane -f | grep "observe"
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Black Box Shows:

observe: external resource differs from desired state
observe: external resource differs from desired state
observe: external resource differs from desired state
(repeating into infinity...)
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Translation: Your composition's idea of "desired state" and the actual cloud resource are having a philosophical disagreement about what reality should be.

Fix: Check your patches and transforms. Somewhere, a field is being converted incorrectly (looking at you, string-to-integer conversions).

Case Study 3: The Ghost Resource

Symptom: kubectl get shows your resource exists, but it's not actually in the cloud.

Investigation:

kubectl logs -n crossplane-system <provider-pod> | grep "cannot create"
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Black Box Confession:

cannot create external resource: InvalidParameterValue: 
The subnet ID 'subnet-12345' does not exist
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Translation: You're trying to build a house on a lot that doesn't exist. Your composition references a subnet that was deleted, moved, or never existed.

Fix: Update your resource references or check your composition parameters.

Advanced Black Box Archaeology

Persistent Logging

By default, logs disappear when pods restart—like an Etch A Sketch getting shaken. For serious investigations, send logs to a permanent archive:

# Using a logging sidecar (example with Fluent Bit)
# Add to your Crossplane deployment
kubectl patch deployment crossplane -n crossplane-system --type='json' \
  -p='[{"op": "add", "path": "/spec/template/spec/containers/-", 
       "value": {"name": "logging-sidecar", "image": "fluent/fluent-bit:latest"}}]'
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Or better yet, use a proper logging solution like:

  • EFK Stack (Elasticsearch, Fluent Bit, Kibana)
  • Loki + Grafana (the hipster choice)
  • CloudWatch / Stackdriver (if you're all-in on a cloud provider)

The Audit Trail

For compliance investigators (yes, infrastructure has CSI too), enable Kubernetes audit logging:

# This captures WHO did WHAT and WHEN
# Configure in your cluster's audit policy
# Details vary by Kubernetes distribution
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Combined with Crossplane logs, you get the full story: "Sarah deployed a Composition at 2 PM that attempted to provision an RDS instance with the root password 'password123'. The provider rejected this faster than you can say 'security audit'."

The Emergency Locator Transmitter

Sometimes you need immediate alerts, not post-crash investigation. Set up monitoring:

# Example Prometheus alert for Crossplane errors
apiVersion: v1
kind: ConfigMap
metadata:
  name: crossplane-alerts
data:
  alerts.yml: |
    groups:
    - name: crossplane
      rules:
      - alert: CrossplaneReconcileFailure
        expr: |
          increase(crossplane_reconcile_errors_total[5m]) > 5
        annotations:
          summary: "Crossplane is having a bad time"
          description: "Multiple reconcile failures detected. Check the black box!"
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The Flight Checklist: Common Log Patterns

🟢 All is Well:

successfully composed resources
observe: external resource is up to date
reconcile succeeded
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🟡 Caution Required:

waiting for dependencies
cannot resolve resource references
requeueing after short wait
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🔴 Emergency Landing:

cannot compose resources
cannot create external resource
authentication failed
forbidden: User cannot create resource
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Best Practices from Veteran Investigators

  1. Log before you fly: Always check logs BEFORE declaring success. Just because kubectl apply succeeded doesn't mean your infrastructure actually provisioned.

  2. Label everything: Use meaningful labels on your resources. Future-you (the crash investigator) will thank present-you.

  3. Document your flight plan: Comment your Compositions. When things go wrong at 3 AM, "# This patches the subnet ID because AWS reasons" is worth its weight in gold.

  4. Test in a simulator first: Use dry-runs and development clusters. Real cloud resources cost real money, and smoking craters in production cost real jobs.

  5. Keep the black box accessible: Don't restrict log access to one person. When that person is on vacation and production is on fire, you'll regret it.

The Post-Incident Report Template

After every crash investigation, document your findings:

## Incident Summary
**Date:** [when it broke]
**Duration:** [how long you suffered]
**Impact:** [what burned]

## Root Cause
[What the black box revealed]

## Timeline
- T-0: User deployed Composition
- T+5m: Resources stuck in Pending
- T+10m: Investigation began
- T+15m: Log analysis revealed [the smoking gun]

## Resolution
[How you fixed it]

## Prevention
[How to never speak of this again]
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Conclusion: Safe Flying

Crossplane logging isn't just about debugging—it's about understanding the story of your infrastructure. Every log line is a breadcrumb trail showing how your desired state became reality (or didn't).

The black box doesn't lie. It might be verbose, scattered across pods, and occasionally cryptic, but it always tells the truth. Learn to read it, and you'll transform from someone who deploys infrastructure to someone who understands infrastructure.

In our next Infrastructure-as-Code Adventure, we'll explore Crossplane troubleshooting patterns—because knowing where the black box is located is only half the battle. The other half is knowing what to do with what you find.

Until then, may your reconciliations be swift, your logs be readable, and your infrastructure stay airborne! ✈️

Further Reading:

Got a Crossplane crash story to share? Drop it in the comments below. We're all learning from each other's flight incidents!

This article is part of the "Infrastructure-as-Code Adventures" series. Check out the previous articles for more tales from the trenches of cloud infrastructure!

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