When a model run spans dozens of GPUs and multiple control planes, the unit of reliability is no longer a single request. It is the whole training trajectory.
Core thesis
Core Insight
Training infrastructure should be designed around the cost of restart, not the cost of steady-state latency.
A simple way to express the tradeoff is:
This framing keeps attention on the expensive failure modes: checkpoint corruption, scheduler churn, and silent accuracy drift.
Implementation sketch
apiVersion: apps/v1
kind: Deployment
metadata:
name: trainer
spec:
replicas: 1
template:
spec:
restartPolicy: Always
containers:
- name: trainer
image: ghcr.io/lab/trainer:latest
env:
- name: CHECKPOINT_INTERVAL
value: '300'
- name: OBSERVABILITY_LEVEL
value: 'trace'
What I would optimize first
- Make checkpoints portable across regions and vendors.
- Emit training metrics as first-class artifacts, not debug logs.
- Keep the control plane small enough that failure domains remain legible.
The architecture is only elegant when a researcher can explain it on a whiteboard and a platform engineer can keep it alive at 2 a.m.