When using Windows containers in Containerd the windows layerFolder is null and the root is blank #1185
Description
Propose to update the Runtime spec to allow for null or empty in the Windows.layerFolder field. I found an issue where this wasn't being parsed correctly: youki-dev/oci-spec-rs#126. It works for HostProcess Containers in the go implementations due the way go serializes lists.
The schema and spec for windows state the layerFolder should be a min of 1 item:
{
"windows": {
"description": "Windows platform-specific configurations",
"type": "object",
"properties": {
"layerFolders": {
"type": "array",
"items": {
"$ref": "defs.json#/definitions/FilePath"
},
"minItems": 1layerFolders (array of strings, REQUIRED) specifies a list of layer folders the container image relies on. The list is ordered from topmost layer to base layer with the last entry being the scratch. layerFolders MUST contain at least one entry.
There was recently work to enable Host Process containers for Windows and a scratch image was created for it. When running that image the runtime config doesn't have a layer folder:
nerdctl run --isolation host -it --rm mcr.microsoft.com/oss/kubernetes/windows-host-process-containers-base-image:v1.0.0 powershell
--- in separate terminal---
cat C:\ProgramData\containerd\state\io.containerd.runtime.v2.task\default\7e41788b49ac0d19003fc126ffb1ced68fbe9ac6cfb355a4bcc3056fc5b6b994\config.json
{
"ociVersion": "1.1.0-rc.1",
"process": {
"terminal": true,
"user": {
"uid": 0,
"gid": 0
},
"args": [
"powershell"
],
"env": [
"PATH="
],
"cwd": ""
},
"root": {
"path": ""
},
"hostname": "7e41788b49ac",
.... snip....
},
"annotations": {
"nerdctl/name": "windows-host-process-containers-base-image-7e417",
"nerdctl/namespace": "default",
"nerdctl/networks": "[\"nat\"]",
"nerdctl/platform": "windows/amd64",
....snip....
},
"windows": {
"layerFolders": null,
"ignoreFlushesDuringBoot": true,
"network": {
"allowUnqualifiedDNSQuery": true
}
}
}