AWS DocumentDB Management Skill

Analyze and manage AWS DocumentDB clusters, instances, and configurations.

MANDATORY: Discovery-First Pattern

Always list clusters before querying specific resources.

Phase 1: Discovery

#!/bin/bash
export AWS_PAGER=""

echo "=== DocumentDB Clusters ==="
aws docdb describe-db-clusters --output text \
  --query 'DBClusters[].[DBClusterIdentifier,Status,Engine,EngineVersion,DBClusterMembers[0].DBInstanceIdentifier]' \
  --filter Name=engine,Values=docdb

echo ""
echo "=== DocumentDB Instances ==="
aws docdb describe-db-instances --output text \
  --query "DBInstances[?Engine=='docdb'].[DBInstanceIdentifier,DBInstanceClass,DBInstanceStatus,AvailabilityZone,DBClusterIdentifier]"

echo ""
echo "=== Cluster Endpoints ==="
aws docdb describe-db-clusters --output text \
  --query 'DBClusters[].[DBClusterIdentifier,Endpoint,ReaderEndpoint,Port]' \
  --filter Name=engine,Values=docdb

echo ""
echo "=== Parameter Groups ==="
aws docdb describe-db-cluster-parameter-groups --output text \
  --query 'DBClusterParameterGroups[].[DBClusterParameterGroupName,DBParameterGroupFamily,Description]'

Phase 2: Analysis

#!/bin/bash
export AWS_PAGER=""

END_TIME=$(date -u +"%Y-%m-%dT%H:%M:%S")
START_TIME=$(date -u -d "7 days ago" +"%Y-%m-%dT%H:%M:%S" 2>/dev/null || date -u -v-7d +"%Y-%m-%dT%H:%M:%S")

echo "=== Cluster Health Metrics ==="
for cluster in $(aws docdb describe-db-clusters --filter Name=engine,Values=docdb --output text --query 'DBClusters[].DBClusterIdentifier'); do
  {
    cpu=$(aws cloudwatch get-metric-statistics --namespace AWS/DocDB --metric-name CPUUtilization \
      --dimensions Name=DBClusterIdentifier,Value="$cluster" \
      --start-time "$START_TIME" --end-time "$END_TIME" --period 604800 --statistics Average \
      --output text --query 'Datapoints[0].Average')
    mem=$(aws cloudwatch get-metric-statistics --namespace AWS/DocDB --metric-name FreeableMemory \
      --dimensions Name=DBClusterIdentifier,Value="$cluster" \
      --start-time "$START_TIME" --end-time "$END_TIME" --period 604800 --statistics Average \
      --output text --query 'Datapoints[0].Average')
    conns=$(aws cloudwatch get-metric-statistics --namespace AWS/DocDB --metric-name DatabaseConnections \
      --dimensions Name=DBClusterIdentifier,Value="$cluster" \
      --start-time "$START_TIME" --end-time "$END_TIME" --period 604800 --statistics Maximum \
      --output text --query 'Datapoints[0].Maximum')
    printf "%s\tCPU:%.1f%%\tFreeMem:%s\tMaxConns:%s\n" "$cluster" "${cpu:-0}" "${mem:-N/A}" "${conns:-0}"
  } &
done
wait

echo ""
echo "=== Snapshots ==="
aws docdb describe-db-cluster-snapshots --output text \
  --query 'DBClusterSnapshots[].[DBClusterSnapshotIdentifier,DBClusterIdentifier,Status,SnapshotCreateTime,SnapshotType]' | head -15

echo ""
echo "=== Pending Maintenance ==="
aws docdb describe-pending-maintenance-actions --output text \
  --query 'PendingMaintenanceActions[].[ResourceIdentifier,PendingMaintenanceActionDetails[0].Action,PendingMaintenanceActionDetails[0].AutoAppliedAfterDate]' 2>/dev/null

echo ""
echo "=== Recent Events ==="
aws docdb describe-events --source-type db-cluster --duration 1440 --output text \
  --query 'Events[].[SourceIdentifier,Message,Date]' | head -10

Output Format

• Target ≤50 lines per output
• Use --output text --query for all commands
• Tab-delimited fields: ClusterId, Status, InstanceClass, Metric
• Aggregate metrics into summary lines per cluster
• Never dump full parameter group values -- show group names only

Anti-Hallucination Rules

1. NEVER assume resource names — always discover via CLI/API in Phase 1 before referencing in Phase 2.
2. NEVER fabricate metric names or dimensions — verify against the service documentation or --help output.
3. NEVER mix CLI commands between service versions — confirm which version/API you are targeting.
4. ALWAYS use the discovery → verify → analyze chain — every resource referenced must have been discovered first.
5. ALWAYS handle empty results gracefully — an empty response is valid data, not an error to retry.

Counter-Rationalizations

Shortcut	Counter	Why
"I'll skip discovery and check known resources"	Always run Phase 1 discovery first	Resource names change, new resources appear — assumed names cause errors
"The user only asked for a quick check"	Follow the full discovery → analysis flow	Quick checks miss critical issues; structured analysis catches silent failures
"Default configuration is probably fine"	Audit configuration explicitly	Defaults often leave logging, security, and optimization features disabled
"Metrics aren't needed for this"	Always check relevant metrics when available	API/CLI responses show current state; metrics reveal trends and intermittent issues
"I don't have access to that"	Try the command and report the actual error	Assumed permission failures prevent useful investigation; actual errors are informative

Common Pitfalls

• Engine filter: DocumentDB uses engine docdb -- always filter to avoid mixing with RDS results
• API compatibility: DocumentDB shares some APIs with RDS (docdb commands map to rds API) -- use aws docdb subcommand
• Elastic clusters: Newer elastic clusters use separate API calls (describe-elastic-clusters)
• TLS required: Default clusters require TLS -- connection failures often relate to missing CA certificate
• Storage auto-scaling: Storage scales automatically up to 128 TiB -- no manual provisioning needed
• Replica lag: Check DBInstanceReplicaLag metric for read replicas -- high lag affects read consistency
• Backup retention: Default is 1 day -- check BackupRetentionPeriod in cluster configuration