Namespace Isolation Patterns

Default K8s: Single Namespace INSECURE
namespace: default
frontend-pod-1
frontend-pod-2
backend-pod-1
backend-pod-2
database-pod
redis-pod
rabbitmq-pod
monitoring-pod
No network isolation (any pod → any pod)
Shared secrets (all accessible)
No resource limits (noisy neighbor)
Same RBAC (everyone can delete everything)
No audit boundaries
Single point of failure
VM World: VLAN Isolation SECURE BY DESIGN
VLAN 100: DMZ
Web Server 1
Web Server 2
Firewall rules enforced
Resource limits: 4 cores each
↓ FIREWALL
VLAN 200: Application
App Server 1
App Server 2
Internal network only
Resource limits: 8 cores each
↓ FIREWALL + JUMP HOST
VLAN 300: Secure Data
Database Server
Isolated + encrypted network
DBA team access only
16 cores / 128GB RAM
Separate kernel per VM
Stacktic K8s: Full Namespace Isolation SECURE + AUTOMATED
namespace: dmz-frontend
nginx-1
nginx-2
nginx-3
NetworkPolicy: Ingress from Internet only
ResourceQuota: 20 CPU / 40Gi Memory
RBAC: frontend-team (limited access)
Secrets: Only frontend secrets visible
↓ NetworkPolicy (port 8080 only)
namespace: secure-backend
api-1
api-2
api-3
NetworkPolicy: Only from dmz-frontend
ResourceQuota: 100 CPU / 200Gi Memory
RBAC: backend-team only
PodSecurity: restricted
↓ NetworkPolicy (port 5432 only)
namespace: critical-database
postgres-primary
postgres-replica
NetworkPolicy: DENY ALL + backend only
ResourceQuota: 50 CPU / 500Gi Mem / 1Ti PVC
RBAC: dba-team only (no dev access)
Encryption: at-rest + in-transit

Isolation Benefits

Security
  • Scoped RBAC/Secrets/NetworkPolicy
  • Smaller blast radius on breach
  • PCI-DSS compliant zones
  • Automated security policies
Resource Management
  • ResourceQuotas per namespace
  • Clear cost attribution
  • Predictable capacity allocation
  • Prevent resource hogging
Operations
  • One command cleanup (delete ns)
  • Problems contained in namespace
  • Simple service discovery
  • Clean audit boundaries