Nova-Rewards

Nova Rewards — DevOps Runbook

Service Architecture Overview

Service	Description
API Server	Node.js REST API handling merchant and user requests. Runs on ECS (Fargate) or EC2 behind an ALB. Connects to RDS (PostgreSQL) and Redis.
Redis (ElastiCache)	In-memory cache and session store. Used by the API server for rate limiting, session tokens, and short-lived data.
Database (RDS PostgreSQL)	Primary persistent store for users, merchants, campaigns, transactions, and redemptions. Multi-AZ enabled in production.
Smart Contract Event Processor	Background service that listens to Soroban/Stellar contract events and writes them to the database. Connects to a Stellar RPC endpoint and RDS.

All services communicate within a private VPC. The ALB is the only public-facing entry point.

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Routine Maintenance

Restart the API Server

Via systemd (EC2):

sudo systemctl restart nova-api

Via ECS (force new deployment):

aws ecs update-service \
  --cluster <placeholder-cluster-name> \
  --service <placeholder-service-name> \
  --force-new-deployment

Redis ElastiCache Failover

Via AWS Console:

1. Go to ElastiCache → Redis clusters → select <placeholder-cluster-name>
2. Actions → Failover Primary

Via CLI:

aws elasticache test-failover \
  --replication-group-id <placeholder-replication-group-id> \
  --node-group-id 0001

RDS Reboot (non-failover)

aws rds reboot-db-instance \
  --db-instance-identifier <placeholder-db-instance-id>

RDS Failover (Multi-AZ)

aws rds failover-db-cluster \
  --db-cluster-identifier <placeholder-db-cluster-id>

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Backup Strategy

Automated RDS Snapshots

• Schedule: Daily automated snapshots
• Retention: 7 days
• Configuration: Set in Terraform (terraform/main.tf → backup_retention_period = 7) or via RDS console under Maintenance & backups.

Manual Snapshot Before Major Deployments

aws rds create-db-snapshot \
  --db-instance-identifier <placeholder-db-instance-id> \
  --db-snapshot-identifier pre-deploy-<date>

Restore from Snapshot

Via AWS Console:

1. RDS → Snapshots → select snapshot → Restore Snapshot
2. Configure instance class, VPC, and security groups to match production
3. Update DATABASE_URL environment variable to point to the restored instance

Via CLI:

aws rds restore-db-instance-from-db-snapshot \
  --db-instance-identifier nova-restored-<date> \
  --db-snapshot-identifier pre-deploy-<date>

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Incident Response Checklist

1. Detect — Alert fired via PagerDuty / CloudWatch, or user report received in support channel
2. Assess — Check CloudWatch dashboards, application logs (ECS log groups), error rates, and affected service health
3. Communicate — Post in <placeholder-incident-slack-channel>, update status page at <placeholder-status-page-url>, assign incident commander
4. Mitigate — Apply immediate fix (restart service, scale up, rollback deployment) to restore service
5. Resolve — Confirm all metrics stable, error rates back to baseline, close PagerDuty incident
6. Post-mortem — Schedule within 48 hours; document findings in docs/ops/post-mortems/YYYY-MM-DD-<title>.md

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Common Alert Runbooks

High CPU

Symptoms: CPU > 80% sustained for 5+ minutes on ECS task or EC2 instance.

Steps:

1. SSH into instance or check ECS task logs for runaway processes
2. Run top or htop to identify the offending process
3. If API server: scale out ECS tasks

   aws ecs update-service \
     --cluster <placeholder-cluster-name> \
     --service <placeholder-service-name> \
     --desired-count <increased-count>
   

4. If EC2: scale the Auto Scaling Group or switch to a larger instance type

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Database Connection Exhaustion

Symptoms: too many connections errors in API logs; RDS DatabaseConnections metric at max.

Steps:

1. Check connection pool config (DB_POOL_MAX env var) — reduce if over-provisioned
2. Restart the API server to flush stale connections (see Restart the API Server)
3. If persistent, enable or switch to RDS Proxy to pool connections at the infrastructure level
4. Check for long-running idle connections:

   SELECT pid, state, query_start, query FROM pg_stat_activity WHERE state = 'idle';
   

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Redis Evictions

Symptoms: evicted_keys metric rising in ElastiCache; cache miss rate increasing.

Steps:

1. Check maxmemory-policy in ElastiCache parameter group — set to allkeys-lru for general caching
2. Review which keys are consuming the most memory using redis-cli --bigkeys
3. If memory is genuinely insufficient, scale up the ElastiCache node type via console or Terraform

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Contract Event Processing Lag

Symptoms: On-chain events not reflected in the database; event processor CloudWatch metric blocks_behind increasing.

Steps:

1. Check event processor logs in CloudWatch (/nova/event-processor)
2. Verify the Stellar RPC endpoint is healthy:

   curl <placeholder-stellar-rpc-url>/health
   

3. If RPC is down, switch to the backup endpoint in the event processor config
4. If blocks were missed, trigger a replay from the last confirmed block:

   # Set START_BLOCK env var and restart the processor
   aws ecs update-service \
     --cluster <placeholder-cluster-name> \
     --service <placeholder-event-processor-service> \
     --force-new-deployment