---
checkId: check.servicegraph.valkey
plugin: stellaops.doctor.servicegraph
severity: warn
tags: [servicegraph, valkey, redis, cache]
---
# Valkey/Redis Connectivity

## What It Checks
Reads `Valkey:ConnectionString`, `Redis:ConnectionString`, `ConnectionStrings:Valkey`, or `ConnectionStrings:Redis`, parses the host and port, and opens a TCP connection.

The check skips when no cache connection string is configured and fails when parsing fails or the target cannot be reached.

## Why It Matters
Cache unavailability affects queue coordination, state caching, and latency-sensitive platform features. A malformed connection string is also an early warning that the environment is not wired correctly.

## Common Causes
- The cache connection string is missing, malformed, or still points to a previous environment
- The Valkey/Redis service is not running
- Container networking or DNS is broken

## How to Fix

### Docker Compose
```yaml
services:
  doctor-web:
    environment:
      Valkey__ConnectionString: valkey:6379,password=${STELLAOPS_VALKEY_PASSWORD}
```

```bash
docker compose -f devops/compose/docker-compose.stella-ops.yml ps valkey
docker compose -f devops/compose/docker-compose.stella-ops.yml exec doctor-web sh -lc "nc -zv valkey 6379"
```

### Bare Metal / systemd
```bash
redis-cli -h <valkey-host> -p 6379 ping
```

### Kubernetes / Helm
Use a cluster-local service name in the connection string and verify the port exposed by the StatefulSet or Service.

## Verification
```bash
stella doctor --check check.servicegraph.valkey
```

## Related Checks
- `check.servicegraph.mq` - both checks validate internal service-network connectivity
- `check.servicegraph.endpoints` - broad service discovery issues usually affect cache endpoints too