We need to deploy docker container on edge devices which wont be having Internet. These device occasionally connect to network and one of the device (lets call it H) on the network will have internet access. So, I want to know how we can update docker containers in such scenario. I imagine following two approaches:
- Create tar of image. Copy it to edge device (say over USB) and then update the image on the edge device.
- Create local registry on device H. Pull the updated image on this device. Make edge device pull only updated layers from this local registry on H.
Q1. Machine H has x86 architecture and edge device is runs arm architecture. Running docker pull command on H wont pull arm image from public docker registry. How can we pull arm image on x86 machine? So that we can follow either of two approaches?
Q2. Our docker image tar is of 300 MB and it may grow. So we will require to copy whole 300 MB image tar from device H to edge device. I believe we can create tar only of whole image. Is it, by any chance possible to create tar of only updated layers or reduce the size of tar by any means? (Our image is minimal built by copying only bindaries to scratch docker image)
Q3. Is there any other better approach? What is usually followed in the industry?