Troubleshoot Redis (OpenTelemetry)

Error message:

'receivers' unknown type: "redis" for id: "redis" (valid values: [elasticsearch hostmetrics ...])

Cause: Your NRDOT version does not include the Redis receiver. The Redis receiver requires NRDOT v1.18.0+.

Fix: Either:

• Upgrade NRDOT to the latest version
• Switch to otelcol-contrib, which includes all community receivers

Error message:

cannot unmarshal the configuration: error reading receivers configuration

Common causes:

• Invalid YAML indentation (mixed tabs and spaces)
• Heredoc issues when creating ConfigMaps from shell scripts
• Missing quotes around endpoint values containing colons

Fix:

$
# Validate YAML syntax
$
python3 -c "import yaml; yaml.safe_load(open('/etc/nrdot-collector/redis-collector-config.yaml'))"

How to check:

$
systemctl status nrdot-collector
$
# or
$
systemctl status otelcol-contrib

Common causes:

• Invalid YAML in the collector configuration file
• Port conflict with another process (check port 13133 for health check)
• Insufficient memory (increase limit_mib in memory_limiter)

Fix:

$
# Check for port conflicts
$
ss -tlnp | grep 13133

Error message:

failed to fetch Redis INFO: dial tcp 127.0.0.1:6379: connect: connection refused

Cause: Redis is not running, wrong endpoint configured, or firewall blocking connection.

Fix:

$
# Verify Redis is running
$
redis-cli ping
$

$
# Test connectivity
$
nc -zv localhost 6379

Error message:

Exporting failed. 403 Forbidden

Cause: Invalid license key or incorrect OTLP endpoint for your region.

Fix:

• Verify your license key is correct and active
• Ensure the OTLP endpoint matches your account region

Verification steps:

1. Check the collector is running:

   bash

   コピー

   $
   systemctl is-active nrdot-collector

2. Check the health endpoint:

   bash

   コピー

   $
   curl http://localhost:13133

3. Test with NRQL:

   FROM Metric SELECT count(*) WHERE metricName LIKE 'redis.%' SINCE 10 minutes ago

   コピー

Error message:

Failed to open file: /var/log/redis/redis-server.log: permission denied

Cause: The collector process doesn't have read access to the Redis log file.

Fix (host-based):

$
# Option 1: Make the log file readable
$
sudo chmod 644 /var/log/redis/redis-server.log
$

$
# Option 2: Add collector user to redis group
$
sudo usermod -a -G redis nrdot-collector

Fix (Kubernetes): Ensure the DaemonSet has the /var/log/pods volume mounted with readOnly: true.

Cause: Pod labels don't match the receiver_creator discovery rule.

Fix:

$
# Check pod labels
$
kubectl get pods -n <namespace> --show-labels | grep redis

Ensure the rule in your ConfigMap matches the labels on your Redis pods. For example, if your pods have app.kubernetes.io/name: redis, update the rule accordingly.

How to check:

$
kubectl get pods -n newrelic
$
kubectl logs -n newrelic <pod-name> --previous

Common causes:

• Invalid ConfigMap YAML (check indentation in the data.config.yaml field)
• Missing Kubernetes secret for credentials
• RBAC permissions missing (for DaemonSet with k8s_observer)

Fix:

$
# Validate ConfigMap content
$
kubectl get configmap otel-collector-redis-config -n newrelic -o jsonpath='{.data.config\.yaml}' | python3 -c "import yaml,sys; yaml.safe_load(sys.stdin); print('Valid YAML')"
$

$
# Check secret exists
$
kubectl get secret newrelic-credentials -n newrelic
$

$
# Check RBAC
$
kubectl auth can-i list pods --as=system:serviceaccount:newrelic:otel-collector-redis

Error: Connection timeout to Redis endpoint.

Fix:

$
# Verify Redis pods are running
$
kubectl get pods -n <namespace> -l app=redis
$

$
# Test connectivity from collector pod
$
kubectl exec -n newrelic <collector-pod> -- nc -zv <redis-pod-ip> 6379

Common causes:

• Namespace doesn't exist

• Invalid values.yaml

• Helm repo not added

  Fix:

  bash

  コピー

  $
  # Create namespace first
  $
  kubectl create namespace newrelic
  $
  
  $
  # Validate (dry run)
  $
  helm template redis-otel open-telemetry/opentelemetry-collector -f values.yaml --dry-run

Symptoms: Instance entities appear but no Redis Cluster entity is created.

Common causes:

• redis.cluster.name not set on the cluster pipeline

• redis.instance.id or server.address present on cluster metrics (prevents cluster entity rule from matching)

• Cluster metrics disabled (all cluster metrics are disabled by default in the Redis receiver)

  Fix: Verify your cluster pipeline has:

• redis.cluster.name set via resource/cluster processor

• server.address: {enabled: false} and server.port: {enabled: false} on the cluster receiver

• No redis.instance.id on the cluster pipeline

  Verify with NRQL:

  SELECT count(*) FROM Metric
  WHERE redis.cluster.name IS NOT NULL
  AND redis.instance.id IS NULL
  AND server.address IS NULL
  SINCE 5 minutes ago

  コピー

  If this returns 0, cluster metrics are not flowing correctly.

Symptoms: Cluster entity exists but dashboard shows empty widgets.

Common causes:

• Redis is not running in Cluster mode (standalone instances don't produce cluster metrics)

• Cluster metrics not enabled in the Redis receiver config

  Fix: Verify Redis is in Cluster mode:

  bash

  コピー

  $
  redis-cli INFO cluster | grep cluster_enabled

  Should return cluster_enabled:1. If it returns 0, your Redis is not in Cluster mode.

  Verify cluster metrics are enabled in your receiver config:

  redis/cluster:
    metrics:
      redis.cluster.state: {enabled: true}
      redis.cluster.known_nodes: {enabled: true}
      # ... all 9 cluster metrics must be explicitly enabled

  コピー

Symptoms: More than one Redis Cluster entity appears for the same cluster.

Cause: Different collectors are using different redis.cluster.name values for the same cluster.

Fix: Ensure all collectors monitoring the same cluster use the exact same redis.cluster.name value in their resource/cluster processor. The cluster entity identifier is this name — different names create different entities.

Symptoms: Both cluster and instance entities exist but no CONTAINS relationship appears in service maps.

Cause: Instance metrics don't carry the redis.cluster.name attribute, so the relationship rule can't link them.

Fix: Add redis.cluster.name to your instance pipeline's resource processor:

resource/redis_identity:
  attributes:
    - key: redis.instance.id
      value: "my-instance:6379"
      action: upsert
    - key: redis.cluster.name
      value: "my-redis-cluster"  # Must match the cluster pipeline value
      action: upsert

Symptoms: redis.cluster.state reports 0 (FAIL) even though Redis appears operational.

Common causes:

• Not all 16384 hash slots are assigned (incomplete cluster setup)

• A master node is down with no available replica for automatic failover

• Network partition between nodes

  Fix:

  bash

  コピー

  $
  # Check cluster state directly
  $
  redis-cli CLUSTER INFO | grep cluster_state
  $
  
  $
  # Check slot coverage
  $
  redis-cli CLUSTER INFO | grep cluster_slots
  $
  
  $
  # Check for failed nodes
  $
  redis-cli CLUSTER NODES | grep fail

  If cluster_slots_assigned is less than 16384, some slots are unassigned. Fix by adding the missing slot ranges to available nodes.