Managing Service Isolation
1. Process Isolation Pattern
| Aspect | Detail |
|---|---|
| Mechanism | Each service in its own OS process |
| Benefit | Crash of one process doesn't take others |
| Implementation | Container, VM, separate JVM |
2. Resource Isolation Pattern
| Resource | Mechanism |
|---|---|
| CPU | cgroups CPU shares, K8s requests/limits |
| Memory | cgroups memory limits, OOM killer scope |
| I/O | blkio throttling |
| Network | tc/qdisc bandwidth shaping |
| FDs / PIDs | ulimit, container limits |
3. Namespace Isolation Pattern
| Linux Namespace | Isolates |
|---|---|
| PID | Process IDs |
| NET | Network stack, interfaces, ports |
| MNT | Filesystem mounts |
| UTS | Hostname |
| IPC | System V IPC, POSIX message queues |
| USER | User/group IDs |
| CGROUP | cgroup root view |
4. Network Isolation Pattern
| Mechanism | Detail |
|---|---|
| Network Policies | K8s NetworkPolicy (default deny + allow rules) |
| VPC / Subnets | Private subnets per service tier |
| Security Groups | L4 firewall rules (AWS/GCP/Azure) |
| Service Mesh mTLS | Identity-based access control |
| Zero Trust | Never trust by network location |
Example: K8s NetworkPolicy
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata: { name: allow-payment-from-order, namespace: prod }
spec:
podSelector: { matchLabels: { app: payment-service } }
ingress:
- from:
- podSelector: { matchLabels: { app: order-service } }
ports: [{ protocol: TCP, port: 8080 }]5. Security Context Isolation Pattern
| Setting | Detail |
|---|---|
| runAsNonRoot | Drop root privileges |
| readOnlyRootFilesystem | Immutable container FS |
| capabilities.drop | Drop ALL Linux caps; add only needed |
| seccomp / AppArmor | Syscall filtering |
| SELinux | Mandatory access control |
6. Fault Isolation Pattern
| Boundary | Detail |
|---|---|
| Bulkhead | Per-dependency thread pools |
| Circuit Breaker | Stop cascades |
| Service Boundaries | Each service deployable independently |
| AZ / Region | Geographic blast radius limits |
7. Deployment Isolation Pattern
| Aspect | Detail |
|---|---|
| Per-Service Pipelines | Independent build, test, deploy |
| Canary Independence | Roll out service A canary without affecting B |
| Rollback Independence | Revert one service without others |
8. Data Isolation Pattern
| Approach | Detail |
|---|---|
| Database per Service | Schema isolation |
| Separate DB Instance | Resource isolation |
| Separate Storage Cluster | Failure isolation |
| Encryption per Service | Cryptographic isolation |
9. Tenant Isolation Pattern
| Model | Isolation Level |
|---|---|
| Silo (DB per tenant) | Highest; expensive |
| Bridge (Schema per tenant) | Mid; logical separation |
| Pool (Shared with discriminator) | Lowest; cheapest |
| Hybrid | Pool for free tier, silo for enterprise |
10. Runtime Isolation Pattern
| Tech | Isolation |
|---|---|
| Container | Namespace + cgroup; shares kernel |
| VM | Hypervisor; full kernel isolation |
| MicroVM | Lightweight VMs (Firecracker, Kata) |
| WASM Sandbox | Capability-based; CPU-only |
| Serverless | Provider-managed isolation per invocation |