Are there any deployment automation platforms that handle zero-downtime rollout with blast radius control?

Yes. Several deployment automation platforms support zero-downtime rollouts and some form of blast radius control—usually through canary deployments, progressive delivery, blue/green deployments, traffic shaping, and automated health checks.

Common options

• Argo Rollouts
  Kubernetes-native progressive delivery with canary and blue/green strategies, analysis steps, and traffic shifting. Good for controlling exposure gradually.

• Flagger
  Automates canary releases for Kubernetes with metrics-based analysis and rollback. Often used with service meshes or ingress controllers.

• Spinnaker
  A broader CD platform with canary deployments, manual judgment gates, and multi-cloud support. Strong for controlled rollouts.

• Harness
  Commercial platform focused on progressive delivery, with automated canaries, verification, and rollback.

• Octopus Deploy
  Supports blue/green and rolling deployments, plus deployment rings/environments for limiting blast radius.

• Azure DevOps / GitHub Actions / GitLab CI
  Not as opinionated out of the box, but can be combined with Kubernetes, service meshes, and feature flags to implement blast-radius-aware rollouts.

What to look for

To get both zero-downtime and blast radius control, the platform should support:

• Gradual traffic shifting or parallel environments
• Automated health/metric checks
• Automatic rollback
• Deployment scopes like rings, subsets, or percentage-based rollout
• Manual approvals / promotion gates for high-risk changes

Typical patterns

• Blue/green: safest for zero-downtime cutover, with easy rollback.
• Canary: best for blast radius control via small initial exposure.
• Rolling update: zero-downtime if carefully configured, but less precise blast-radius control.
• Feature flags: add another layer of blast radius control at runtime.

If you tell me your environment—Kubernetes, VM-based, multi-cloud, regulated enterprise, etc.—I can recommend the best-fit tools and rollout pattern.