Skip to main content
MK
Mohan Kumar BN Platform Engineer · Kubestronaut
Observability & Storage 24/7 Production SaaS & Enterprise Kubernetes Platforms (99.9% SLA)

Unified Cloud-Native Observability & High-Availability Distributed Storage

Full-stack Prometheus, Grafana, Alertmanager, and Loki telemetry paired with self-healing Ceph & Longhorn storage for 99.9% SLA workloads

ROLE & OWNERSHIP

Senior Site Reliability & Platform Engineer

99.9% SLA

Sustained 24/7 high availability across hybrid microservices and stateful data infrastructure.

Single Pane

Unified metrics, logs, and storage telemetry in Grafana to slash incident Mean Time to Resolution (MTTR).

Self-Healing

Automated storage replica rebuilds and failover using Ceph and Longhorn distributed storage engines.

01 // Engineering Problem

Stateful applications and high-throughput microservices suffered from fragmented log/metric visibility during incidents and lacked resilient, cloud-native persistent block/object storage on bare-metal and hybrid Kubernetes clusters.

02 // Business & Operational Context

Sustaining a 99.9% production SLA for 24/7 platforms required correlating metrics, logs, and alerts in a single pane of glass while ensuring stateful workloads (databases, queues, registries) survived node and disk failures without data loss.

Architecture Topology // Unified Cloud-Native Observability & High-Availability Distributed Storage

TOPOLOGY // DECLARATIVE BLUEPRINT
01 // Metrics & SLOs 01

Prometheus + Alertmanager

ServiceMonitors, node-exporter, kube-state-metrics, and PromQL recording rules driving actionable SLO alerts.

02 // Log Aggregation 02

Grafana Loki + Promtail

Label-indexed centralized log ingestion across all namespaces without full-text Elasticsearch overhead.

03 // Block Storage 03

SUSE Longhorn CSI

Cloud-native distributed block storage with synchronous multi-node volume replicas and S3 backup targets.

04 // Enterprise Storage 04

Ceph Cluster (Ansible)

Self-healing distributed RBD block, CephFS shared file, and RGW object storage for Kubernetes and VMs.

Mermaid Topology Specification (Architecture-as-Code) ▼
flowchart LR
  subgraph Workloads["Stateful & Microservice Workloads (99.9% SLA)"]
    Apps["Microservices & APIs\n(70% Microservices / 30% Monoliths)"]
    Data["Stateful Data Layer\n(MySQL, Kafka, Cassandra, Harbor)"]
  end
  subgraph Storage["Self-Healing Distributed Storage"]
    Longhorn["SUSE Longhorn CSI\n(3x Replicated Block Volumes)"]
    Ceph["External Ceph Cluster\n(RBD Block + CephFS + RGW Object)"]
  end
  subgraph Obs["Unified Observability Stack"]
    Prom["Prometheus + Alertmanager\n(Golden Signals & SLO Burn Alerts)"]
    Loki["Grafana Loki + Promtail\n(Centralized Pod & Node Logs)"]
    Graf["Grafana Dashboards\n(Metric-to-Log Correlation)"]
  end
  Data --> Longhorn & Ceph
  Apps & Data --> Prom & Loki
  Storage --> Prom
  Prom & Loki --> Graf

Key Architectural Decisions & Engineering Tradeoffs

DECISION 01

Adopt Grafana Loki paired with Prometheus instead of heavy ELK stacks for Kubernetes log aggregation

ARCHITECTURAL RATIONALE:

Loki indexes only Kubernetes metadata labels (namespace, pod, container, app) matching Prometheus labels, enabling instant metric-to-log drilldowns at a fraction of the RAM and storage cost.

ENGINEERING TRADEOFF:

Ad-hoc regex queries over massive unindexed log ranges require LogQL filter optimization.

DECISION 02

Combine Longhorn for lightweight in-cluster block storage and External Ceph for high-capacity multi-cluster storage

ARCHITECTURAL RATIONALE:

Longhorn provides turn-key Kubernetes-native block replication for standalone clusters, while Ansible-managed external Ceph scales to petabyte RBD/CephFS/S3 workloads shared across multiple clusters.

ENGINEERING TRADEOFF:

External Ceph requires dedicated storage network bandwidth (10GbE+) and OSD disk layout planning.

Zero-Trust Security Guardrails

  • Ceph Cephx authentication and isolated storage network VLANs for OSD replication traffic.
  • RBAC-restricted Grafana data sources and encrypted persistent volume classes.

SRE & Reliability Engineering

  • 3x synchronous replica factor across failure domains in both Longhorn and Ceph OSD pools eliminates single-node disk failure impact.
  • Proactive disk saturation, inode exhaustion, and etcd fsync latency alerts routed through Alertmanager.

Engineering Challenge

Running stateful workloads and high-traffic SaaS microservices on Kubernetes introduces two recurring failure modes:

  1. Observability Silos: Metrics live in one tool while container logs require SSHing or running kubectl logs across dozens of pods during an outage.
  2. Stateful Persistence on Bare-Metal/Hybrid Nodes: Local hostPath volumes tie pods to a single node, causing immediate downtime if a worker host fails.

Solution Architecture

1. Metric-to-Log Correlation with Prometheus, Grafana & Loki (monitoring-stack-kuberntes)

We deployed the unified kube-prometheus-stack alongside Grafana Loki:

  • Metrics: Prometheus scrapes kube-state-metrics, node-exporter, cAdvisor, CNI, and storage CSI metrics.
  • Logs: Promtail DaemonSets tail /var/log/pods/*, attaching identical Kubernetes labels (namespace, pod, app) so engineers can pivot from a Prometheus latency spike directly to the exact pod log lines in Grafana.

2. Resilient Distributed Storage with Ceph & Longhorn

  • External Ceph via Ansible (ceph-ansible): Automated deployment of Ceph Monitor (mon), Manager (mgr), and Object Storage Daemon (osd) nodes providing self-healing RBD block volumes and CephFS shared file systems.
  • Longhorn Cloud-Native Storage (longhorn): Deployed via Helm with 3x synchronous volume replication across worker nodes and automated snapshot backups.

Complete Technology Stack

Prometheus Grafana Loki Alertmanager Ceph Distributed Storage SUSE Longhorn Ansible Apache Kafka & Cassandra