Stack Comparison
This section evaluates three centralized logging stacks for HA, on-premise Kubernetes infrastructure:
- Grafana Loki Stack (with Promtail or Fluent Bit)
- ELK Stack (Elasticsearch + Logstash + Kibana)
- Graylog Stack (Graylog + MongoDB + Elasticsearch)
Each stack is reviewed based on high availability, Kubernetes compatibility, resource usage, scalability, storage, and operational complexity.
📊 Comparison Table
| Feature / Stack | Grafana Loki Stack | ELK Stack | Graylog Stack |
|---|---|---|---|
| Kubernetes Native | ✅ Helm charts, Promtail as DaemonSet | ⚠️ Complex, Logstash not native | ❌ Mostly manual setup |
| HA Support | ✅ StatefulSet ingesters, no SPOF | ✅ Multi-node ES, Logstash HA possible | ⚠️ MongoDB & Graylog bottlenecks |
| Log Format Support | ✅ JSON, Labels (prometheus-style) | ✅ JSON & full-text search | ✅ JSON, syslog, GELF |
| Storage Backend | ✅ S3/MinIO, PVC supported | ✅ PVC, NFS, CephFS | ✅ PVC, NFS, CephFS |
| Scalability | ✅ Horizontal scaling via microservices | ✅ High but resource-heavy | ⚠️ Limited, not for large scale |
| Resource Usage | ⚡ Lightweight (no indexing) | 🔥 Very high (ES + Logstash) | ⚠️ High (ES + MongoDB + Graylog) |
| Visualization | Grafana | Kibana | Graylog UI |
| Alerting | Grafana Alerting | Watcher / ElastAlert / OpenSearch | Graylog Alerts |
| Deployment Simplicity | ✅ Helm-native, fast to deploy | ⚠️ Needs tuning, complex pipeline | ❌ More manual configuration |
| Community & Docs | Large (Grafana ecosystem) | Mature, extensive | Niche but active |
🏁 Summary of Evaluation
🔷 Grafana Loki Stack
- Pros:
- Kubernetes-native and lightweight
- Optimized for structured logs (labels, JSON)
- Easy to deploy with Helm
- Scales well for most use cases
- Cons:
- Not designed for full-text log search
- Depends on external storage (S3/MinIO)
🔷 ELK Stack
- Pros:
- Powerful full-text search
- Rich ecosystem (Logstash filters, Beats agents)
- Battle-tested in production environments
- Cons:
- Very heavy on resources (CPU, RAM, disk)
- Logstash configuration can be complex
- Needs more tuning for HA in Kubernetes
🔷 Graylog Stack
- Pros:
- Good built-in UI for filtering and alerting
- Suitable for syslog-based or security-focused use cases
- Cons:
- HA requires MongoDB replica setup
- Less Kubernetes-native
- Less community adoption in cloud-native setups
🥇 Recommended Stack for On-Prem Kubernetes
Based on the criteria above, the Grafana Loki Stack is recommended for on-premise Kubernetes deployments due to its simplicity, HA readiness, Kubernetes-native architecture, and lightweight performance.
🧪 Next Step
We will proceed by designing a Highly Available Loki Stack architecture and preparing its Helm-based deployment plan with MinIO as storage.