Docker-registry
Service that stores component docker images and used to push/pull images to start. Kubernetes uses it to pull images for Flow steps.
Downtime
Very bad
The downtime is Bad. Step pods may not start (e.g. pod start due to Flow start or ordinary Flow wake-ups). Component pushes into the Gitreceiver won’t work.
Scaling
Scalable to any reasonable amount of pods. But backend storage should be able to handle this. Sticky sessions (in terms of client IP address) require a balancer in front of the registry.
Deployment
Use rolling release. Replace pods one by one. It’s forbidden to have zero pods.
Strong dependencies
Backend storage (NFS at Platform installations).