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adds containerd-shim-lcow-v2 shim - #2627

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Harsh Rawat (rawahars) merged 6 commits into
microsoft:mainfrom
rawahars:lcow-shim-draft
Mar 19, 2026
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adds containerd-shim-lcow-v2 shim#2627
Harsh Rawat (rawahars) merged 6 commits into
microsoft:mainfrom
rawahars:lcow-shim-draft

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@rawaharsHarsh Rawat (rawahars) commented Mar 10, 2026•
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Summary

This pull request introduces a new implementation of the containerd-shim-lcow-v2 for Windows, used for running Linux Containers on Windows.

The changes cover the main entrypoint, shim manager logic, plugin registration, shared service implementation, and a manifest for proper Windows compatibility. The uber changes are-

  • The main entrypoint and supporting logic to start + serve the shim server.
  • The stubs for Task Service and Shimdiag service.
  • The implementation for Sandbox service.
  • The implementation for VM Controller which manages the VM lifecycle and operations.

This shim follows the upstream pattern of using containerd/pkg/shim for managing it's lifecycle. It uses plugin mechanism for registering service with containerd and is initialized during startup.

This PR is dependent upon PR #2612 and PR #2616

@rawahars
Harsh Rawat (rawahars) requested a review from a team as a code ownerMarch 10, 2026 11:31
jterry75
Justin (jterry75) reviewed Mar 10, 2026
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Comment threadcmd/containerd-shim-lcow-v1/service/plugin/plugin.go Outdated
Comment threadcmd/containerd-shim-lcow-v2/service/service.go
Comment threadcmd/containerd-shim-lcow-v1/service/service.go Outdated
Comment threadcmd/containerd-shim-lcow-v1/service/service_sandbox.go Outdated
Comment threadcmd/containerd-shim-lcow-v1/service/service_sandbox.go Outdated
Comment threadinternal/controller/vm/status.go Outdated
Comment threadinternal/controller/vm/vm.go Outdated
Comment threadinternal/controller/vm/vm.go Outdated
Comment threadinternal/controller/vm/vm.go
Comment threadinternal/controller/vm/vm.go Outdated
@rawahars
added containerd-shim-lcow-v1 shim draft
a69748e
In this commit, we are adding the initial draft of `containerd-shim-lcow-v1`. This shim is used for running Linux Containers on Windows.
As part of this commit, we are adding the following-
- The main entrypoint and supporting logic to start + serve the shim server.
- The stubs for Task Service and Shimdiag service.
- The implementation for `Sandbox` service.
- The implementation for `VM Controller` which manages the VM lifecycle and operations.
Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
@rawahars
Harsh Rawat (rawahars)force-pushed the lcow-shim-draft branch 5 times, most recently from 6777136 to 1bb1938CompareMarch 15, 2026 11:31
@rawahars
address review comments
a457c22
Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
helsaawy
Hamza El-Saawy (helsaawy) reviewed Mar 16, 2026
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Comment threadcmd/containerd-shim-lcow-v2/service/service.go
Comment threadcmd/containerd-shim-lcow-v2/service/service_shimdiag_internal.go Outdated
Comment threadcmd/containerd-shim-lcow-v2/service/service_shimdiag_internal.go
Comment threadinternal/builder/vm/lcow/specs.go
Comment threadinternal/controller/vm/vm.go Outdated
Comment threadinternal/controller/vm/vm.go Outdated
Comment threadinternal/logfields/fields.go
Comment threadinternal/logfields/fields.go Outdated
@rawahars
address review comments: 2
49b2b66
Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
shreyanshjain7174
Shreyansh Sancheti (shreyanshjain7174) reviewed Mar 17, 2026
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@shreyanshjain7174Shreyansh Sancheti (shreyanshjain7174) left a comment

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Review of the critical items — each comment is a question for clarification.

Comment threadinternal/controller/vm/vm.go
Comment threadinternal/controller/vm/vm_wcow.go
Comment threadinternal/controller/vm/vm_wcow.go
Comment threadinternal/controller/vm/vm.go
Comment threadinternal/controller/vm/vm.go
Comment threadcmd/containerd-shim-lcow-v2/manager.go
@rawahars
address review comments: 3
fb7c159
Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
helsaawy
Hamza El-Saawy (helsaawy) reviewed Mar 17, 2026
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@helsaawyHamza El-Saawy (helsaawy) left a comment

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nits

Comment threadinternal/vm/vmutils/constants.go Outdated

const (
// LCOWShimName is the name of the LCOW shim implementation.
LCOWShimName = "containerd-shim-lcow-v2"

@helsaawyHamza El-Saawy (helsaawy)Mar 17, 2026

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can you move this to cmd/containerd-shim-lcow-v2? this should be the app name for the shim, and there shouldn't be a need for any code outside of the shim binary code to use/access it

@rawaharsHarsh Rawat (rawahars)Mar 17, 2026

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Relocated the constant to the service package. Since main can import service but not vice versa without creating circular dependencies, this move ensures the name is available to both.

Comment threadcmd/containerd-shim-lcow-v2/service/service_sandbox_internal.go Outdated
Comment threadcmd/containerd-shim-lcow-v2/service/service_sandbox.go Outdated
@rawahars
address review comments: 4
75c9b31
Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
jterry75
Justin (jterry75) approved these changes Mar 17, 2026
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Comment threadcmd/containerd-shim-lcow-v2/service/plugin/plugin.go
Comment threadcmd/containerd-shim-lcow-v2/service/plugin/plugin.go Outdated

const (
// etwProviderName is the ETW provider name for lcow shim.
etwProviderName = "Microsoft.Virtualization.RunHCSLCOW"

@jterry75Justin (jterry75)Mar 17, 2026

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I wonder if we should leave the provider name alone so we just need 1 log stream registered

@rawaharsHarsh Rawat (rawahars)Mar 19, 2026

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Changed the name of provider to Microsoft.Virtualization.containerd-shim-lcow-v2

@rawaharsHarsh Rawat (rawahars) changed the title adds containerd-shim-lcow-v1 shimadds containerd-shim-lcow-v2 shimMar 17, 2026
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@rawahars
address review comments: 5
1ac30a5
Signed-off-by: Harsh Rawat <harshrawat@microsoft.com>
helsaawy
Hamza El-Saawy (helsaawy) approved these changes Mar 19, 2026
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@helsaawyHamza El-Saawy (helsaawy) left a comment

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lgtm

Comment threadcmd/containerd-shim-lcow-v2/service/plugin/plugin.go

const (
// etwProviderName is the ETW provider name for lcow shim.
etwProviderName = "Microsoft.Virtualization.containerd-shim-lcow-v2"

@helsaawyHamza El-Saawy (helsaawy)Mar 19, 2026

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Suggested change
etwProviderName="Microsoft.Virtualization.containerd-shim-lcow-v2"
etwProviderName="Microsoft.Virtualization"+ShimName

@rawahars
Harsh Rawat (rawahars) merged commit c70fd9f into microsoft:mainMar 19, 2026
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@rawahars
Harsh Rawat (rawahars) deleted the lcow-shim-draft branch March 19, 2026 21:05
@rawaharsHarsh Rawat (rawahars) mentioned this pull request Apr 8, 2026
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@shreyanshjain7174Shreyansh Sancheti (shreyanshjain7174)shreyanshjain7174 left review comments
@jterry75Justin (jterry75)jterry75 approved these changes
@helsaawyHamza El-Saawy (helsaawy)helsaawy approved these changes

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