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moby--moby/pkg/system/init_windows.go

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package system // import "github.com/docker/docker/pkg/system"
Windows: Experimental: Allow containerd for runtime Signed-off-by: John Howard <jhoward@microsoft.com> This is the first step in refactoring moby (dockerd) to use containerd on Windows. Similar to the current model in Linux, this adds the option to enable it for runtime. It does not switch the graphdriver to containerd snapshotters. - Refactors libcontainerd to a series of subpackages so that either a "local" containerd (1) or a "remote" (2) containerd can be loaded as opposed to conditional compile as "local" for Windows and "remote" for Linux. - Updates libcontainerd such that Windows has an option to allow the use of a "remote" containerd. Here, it communicates over a named pipe using GRPC. This is currently guarded behind the experimental flag, an environment variable, and the providing of a pipename to connect to containerd. - Infrastructure pieces such as under pkg/system to have helper functions for determining whether containerd is being used. (1) "local" containerd is what the daemon on Windows has used since inception. It's not really containerd at all - it's simply local invocation of HCS APIs directly in-process from the daemon through the Microsoft/hcsshim library. (2) "remote" containerd is what docker on Linux uses for it's runtime. It means that there is a separate containerd service running, and docker communicates over GRPC to it. To try this out, you will need to start with something like the following: Window 1: containerd --log-level debug Window 2: $env:DOCKER_WINDOWS_CONTAINERD=1 dockerd --experimental -D --containerd \\.\pipe\containerd-containerd You will need the following binary from github.com/containerd/containerd in your path: - containerd.exe You will need the following binaries from github.com/Microsoft/hcsshim in your path: - runhcs.exe - containerd-shim-runhcs-v1.exe For LCOW, it will require and initrd.img and kernel in `C:\Program Files\Linux Containers`. This is no different to the current requirements. However, you may need updated binaries, particularly initrd.img built from Microsoft/opengcs as (at the time of writing), Linuxkit binaries are somewhat out of date. Note that containerd and hcsshim for HCS v2 APIs do not yet support all the required functionality needed for docker. This will come in time - this is a baby (although large) step to migrating Docker on Windows to containerd. Note that the HCS v2 APIs are only called on RS5+ builds. RS1..RS4 will still use HCS v1 APIs as the v2 APIs were not fully developed enough on these builds to be usable. This abstraction is done in HCSShim. (Referring specifically to runtime) Note the LCOW graphdriver still uses HCS v1 APIs regardless. Note also that this does not migrate docker to use containerd snapshotters rather than graphdrivers. This needs to be done in conjunction with Linux also doing the same switch.
2019-01-08 17:30:52 -05:00
import (
"os"
"github.com/sirupsen/logrus"
)
var (
// containerdRuntimeSupported determines if ContainerD should be the runtime.
// As of March 2019, this is an experimental feature.
containerdRuntimeSupported = false
)
Windows: Experimental: Allow containerd for runtime Signed-off-by: John Howard <jhoward@microsoft.com> This is the first step in refactoring moby (dockerd) to use containerd on Windows. Similar to the current model in Linux, this adds the option to enable it for runtime. It does not switch the graphdriver to containerd snapshotters. - Refactors libcontainerd to a series of subpackages so that either a "local" containerd (1) or a "remote" (2) containerd can be loaded as opposed to conditional compile as "local" for Windows and "remote" for Linux. - Updates libcontainerd such that Windows has an option to allow the use of a "remote" containerd. Here, it communicates over a named pipe using GRPC. This is currently guarded behind the experimental flag, an environment variable, and the providing of a pipename to connect to containerd. - Infrastructure pieces such as under pkg/system to have helper functions for determining whether containerd is being used. (1) "local" containerd is what the daemon on Windows has used since inception. It's not really containerd at all - it's simply local invocation of HCS APIs directly in-process from the daemon through the Microsoft/hcsshim library. (2) "remote" containerd is what docker on Linux uses for it's runtime. It means that there is a separate containerd service running, and docker communicates over GRPC to it. To try this out, you will need to start with something like the following: Window 1: containerd --log-level debug Window 2: $env:DOCKER_WINDOWS_CONTAINERD=1 dockerd --experimental -D --containerd \\.\pipe\containerd-containerd You will need the following binary from github.com/containerd/containerd in your path: - containerd.exe You will need the following binaries from github.com/Microsoft/hcsshim in your path: - runhcs.exe - containerd-shim-runhcs-v1.exe For LCOW, it will require and initrd.img and kernel in `C:\Program Files\Linux Containers`. This is no different to the current requirements. However, you may need updated binaries, particularly initrd.img built from Microsoft/opengcs as (at the time of writing), Linuxkit binaries are somewhat out of date. Note that containerd and hcsshim for HCS v2 APIs do not yet support all the required functionality needed for docker. This will come in time - this is a baby (although large) step to migrating Docker on Windows to containerd. Note that the HCS v2 APIs are only called on RS5+ builds. RS1..RS4 will still use HCS v1 APIs as the v2 APIs were not fully developed enough on these builds to be usable. This abstraction is done in HCSShim. (Referring specifically to runtime) Note the LCOW graphdriver still uses HCS v1 APIs regardless. Note also that this does not migrate docker to use containerd snapshotters rather than graphdrivers. This needs to be done in conjunction with Linux also doing the same switch.
2019-01-08 17:30:52 -05:00
// InitContainerdRuntime sets whether to use ContainerD for runtime
// on Windows. This is an experimental feature still in development, and
// also requires an environment variable to be set (so as not to turn the
// feature on from simply experimental which would also mean LCOW.
func InitContainerdRuntime(experimental bool, cdPath string) {
if experimental && len(cdPath) > 0 && len(os.Getenv("DOCKER_WINDOWS_CONTAINERD_RUNTIME")) > 0 {
logrus.Warnf("Using ContainerD runtime. This feature is experimental")
containerdRuntimeSupported = true
}
}
// ContainerdRuntimeSupported returns true if the use of ContainerD runtime is supported.
func ContainerdRuntimeSupported() bool {
return containerdRuntimeSupported
}