Multi-stage builds are a feature of Docker that allows you to use multiple FROM statements in your Dockerfile. Each FROM statement creates a new stage of the build, which can use a different base image and run different commands. You can then copy artifacts from one stage to another, leaving behind everything you don't want in the final image. This optimizes the image size and reduces the attack surface by removing unnecessary dependencies and tools. For example, you can use a stage to compile your code, and then copy only the executable file to the final stage, which can use a minimal base image like scratch. This way, you don't need to include the compiler or the source code in the final image.Reference:

Multi-stage builds | Docker Docs

What Are Multi-Stage Docker Builds? - How-To Geek

Multi-stage | Docker Docs

Image role-based access control isnota function of UCP. UCP has its own built-in authentication mechanism and integrates with LDAP services.It also has role-based access control (RBAC), so that you can control who can access and make changes to your cluster and applications1.However, image role-based access control is a feature of Docker Trusted Registry (DTR), which integrates with UCP and allows you to manage the images you use for your applications2.DTR lets you define granular permissions for images, such as who can push, pull, delete, or scan them3.Reference:Universal Control Plane overview), Docker Trusted Registry overview),Docker Access Control)

The commanddocker network create -d overlay -o encrypted=true <network-name>will ensure that overlay traffic between service tasks is encrypted. This command creates an overlay network with the encryption option enabled, which means that Docker will create IPSEC tunnels between all the nodes where tasks are scheduled for services attached to the overlay network.These tunnels use the AES algorithm in GCM mode and manager nodes automatically rotate the keys every 12 hours1. This way, the data exchanged between containers on different nodes on the overlay network is secured.Reference:

Overlay network driver

: = The livenessProbe is a mechanism that checks if the container is alive and healthy, and restarts it if it fails1.The orchestrator is the component that manages the deployment and scaling of containers across a cluster of nodes2.The action taken by the orchestrator to fix the unhealthy container isnotto autoscale back and delete the pod, but torecreatethe pod on the same or a different node3. This ensures that the desired number of replicas for the pod is maintained, and that the pod can resume its normal operation. Autoscaling back and deleting the pod would reduce the availability and performance of the service, and would not necessarily alleviate the load.

Configure Liveness, Readiness and Startup Probes | Kubernetes

What is a Container Orchestrator? | Docker

Pod Lifecycle | Kubernetes

I hope this helps you understand the concept of livenessProbe and orchestrator, and how they work with Docker and Kubernetes. If you have any other questions related to Docker, please feel free to ask me.

Deleting the image and the image repository from Docker Trusted Registry will not completely delete the image from disk. This is because deleting a repository or a tag only removes the reference to the image, but not the image itself.The image is still stored as a blob on the disk, and can be accessed by its digest1.To completely delete the image from disk, you need to enable the deletion feature in the registry configuration, and then use the API to delete the image by its manifest2.Alternatively, you can manually delete the image files from the registry storage directory, but this is not recommended3.After deleting the image, you also need to run the garbage collector to reclaim the disk space4.Reference:

Docker Registry HTTP API V2

How to delete images from a private docker registry?

Remove docker image in registry by removing files/folders on server

Garbage collection