Windows HostProcess Beta 1.23 Documentation (#30391)

* Added initial version change

* Added more information for HostProcess in 1.23, removed content relating to 1.22 specifically.

* Made containerd mention specific to 1.6

* Added note about base images and removed annotation mentions

* Reworded prerequisites section.
This commit is contained in:
Brandon Smith
2021-11-30 15:49:17 -08:00
committed by GitHub
parent 0660f9a376
commit 6a684469cb
2 changed files with 66 additions and 75 deletions
@@ -203,7 +203,7 @@ different Kubernetes components.
| `WinDSR` | `false` | Alpha | 1.14 | | | `WinDSR` | `false` | Alpha | 1.14 | |
| `WinOverlay` | `false` | Alpha | 1.14 | 1.19 | | `WinOverlay` | `false` | Alpha | 1.14 | 1.19 |
| `WinOverlay` | `true` | Beta | 1.20 | | | `WinOverlay` | `true` | Beta | 1.20 | |
| `WindowsHostProcessContainers` | `false` | Alpha | 1.22 | | | `WindowsHostProcessContainers` | `false` | Beta | 1.23 | |
{{< /table >}} {{< /table >}}
### Feature gates for graduated or deprecated features ### Feature gates for graduated or deprecated features
@@ -7,7 +7,7 @@ min-kubernetes-server-version: 1.22
<!-- overview --> <!-- overview -->
{{< feature-state for_k8s_version="v1.22" state="alpha" >}} {{< feature-state for_k8s_version="v1.23" state="beta" >}}
Windows HostProcess containers enable you to run containerized Windows HostProcess containers enable you to run containerized
workloads on a Windows host. These containers operate as workloads on a Windows host. These containers operate as
@@ -28,7 +28,9 @@ to give it a clean and consolidated workspace. HostProcess containers can also b
top of existing Windows base images and do not inherit the same top of existing Windows base images and do not inherit the same
[compatibility requirements](https://docs.microsoft.com/virtualization/windowscontainers/deploy-containers/version-compatibility) [compatibility requirements](https://docs.microsoft.com/virtualization/windowscontainers/deploy-containers/version-compatibility)
as Windows server containers, meaning that the version of the base images does not need as Windows server containers, meaning that the version of the base images does not need
to match that of the host. HostProcess containers also support to match that of the host. It is, however, recommended that you use the same base image
version as your Windows Server container workloads to ensure you do not have any unused
images taking up space on the node. HostProcess containers also support
[volume mounts](./create-hostprocess-pod#volume-mounts) within the container volume. [volume mounts](./create-hostprocess-pod#volume-mounts) within the container volume.
### When should I use a Windows HostProcess container? ### When should I use a Windows HostProcess container?
@@ -41,56 +43,36 @@ HostProcess containers have access to the host's network interfaces and IP addre
privileges needed by Windows nodes. privileges needed by Windows nodes.
## {{% heading "prerequisites" %}} ## {{% heading "prerequisites" %}}% version-check %}}
{{% version-check %}} In 1.23 the HostProcess container feature is enabled by default. The kublet will
communicate with containerd directly by passing the hostprocess flag via CRI. You can use the
latest version of containerd (v1.6+) to run HostProcess containers.
[How to install containerd.](/docs/setup/production-environment/container-runtimes/#containerd)
To *disable* HostProcess containers you need to pass the following feature gate flag to the
**kubelet** and **kube-apiserver**:
```powershell
--feature-gates=WindowsHostProcessContainers=false
```
To enable HostProcess containers while in Alpha you need to pass the following feature gate flag to
**kubelet** and **kube-apiserver**.
See [Features Gates](/docs/reference/command-line-tools-reference/feature-gates/#overview) See [Features Gates](/docs/reference/command-line-tools-reference/feature-gates/#overview)
documentation for more details. documentation for more details.
```
--feature-gates=WindowsHostProcessContainers=true
```
You can use the latest version of Containerd (v1.5.4+) with the following settings using the containerd
v2 configuration. Add these annotations to any runtime configurations were you wish to enable the
HostProcess container feature.
```
[plugins]
[plugins."io.containerd.grpc.v1.cri"]
[plugins."io.containerd.grpc.v1.cri".containerd]
[plugins."io.containerd.grpc.v1.cri".containerd.default_runtime]
container_annotations = ["microsoft.com/hostprocess-container"]
pod_annotations = ["microsoft.com/hostprocess-container"]
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes]
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runhcs-wcow-process]
container_annotations = ["microsoft.com/hostprocess-container"]
pod_annotations = ["microsoft.com/hostprocess-container"]
```
The current versions of containerd ship with a version of hcsshim that does not have support.
You will need to build a version of hcsshim from the main branch following the
[instructions in hcsshim](https://github.com/Microsoft/hcsshim/#containerd-shim).
Once the containerd shim is built you can replace the file in your contianerd installation.
For example if you followed the instructions to
[install containerd](/docs/setup/production-environment/container-runtimes/#containerd)
replace the `containerd-shim-runhcs-v1.exe` is installed at `$Env:ProgramFiles\containerd` with the newly built shim.
## Limitations ## Limitations
- HostProcess containers require version 1.5.4 or higher of the containerd {{< glossary_tooltip text="container runtime" term_id="container-runtime" >}}. - HostProcess containers require containerd 1.6 or higher
- As of v1.22 HostProcess pods can only contain HostProcess containers. This is a current limitation {{< glossary_tooltip text="container runtime" term_id="container-runtime" >}}.
- As of v1.23 HostProcess pods can only contain HostProcess containers. This is a current limitation
of the Windows OS; non-privileged Windows containers cannot share a vNIC with the host IP namespace. of the Windows OS; non-privileged Windows containers cannot share a vNIC with the host IP namespace.
- HostProcess containers run as a process on the host and do not have any degree of - HostProcess containers run as a process on the host and do not have any degree of
isolation other than resource constraints imposed on the HostProcess user account. Neither isolation other than resource constraints imposed on the HostProcess user account. Neither
filesystem or Hyper-V isolation are supported for HostProcess containers. filesystem or Hyper-V isolation are supported for HostProcess containers.
- Volume mounts are supported and are mounted under the container volume. - Volume mounts are supported and are mounted under the container volume. See [Volume Mounts](#volume-mounts)
See [Volume Mounts](#volume-mounts) - As of 1.23, a limited set of host user accounts are available for HostProcess containers by default.
- A limited set of host user accounts are available for HostProcess containers by default.
See [Choosing a User Account](#choosing-a-user-account). See [Choosing a User Account](#choosing-a-user-account).
- Resource limits (disk, memory, cpu count) are supported in the same fashion as processes - Resource limits (disk, memory, cpu count) are supported in the same fashion as processes
on the host. on the host.
@@ -187,7 +169,7 @@ spec:
HostProcess containers support the ability to mount volumes within the container volume space. HostProcess containers support the ability to mount volumes within the container volume space.
Applications running inside the container can access volume mounts directly via relative or Applications running inside the container can access volume mounts directly via relative or
absolute paths. An environment variable `$CONTAINER_SANDBOX_MOUNT_POINT` is set upon container absolute paths. As of v1.23, an environment variable `$CONTAINER_SANDBOX_MOUNT_POINT` is set upon container
creation and provides the absolute host path to the container volume. Relative paths are based creation and provides the absolute host path to the container volume. Relative paths are based
upon the `Pod.containers.volumeMounts.mountPath` configuration. upon the `Pod.containers.volumeMounts.mountPath` configuration.
@@ -199,13 +181,22 @@ To access service account tokens the following path structures are supported wit
`$CONTAINER_SANDBOX_MOUNT_POINT\var\run\secrets\kubernetes.io\serviceaccount\` `$CONTAINER_SANDBOX_MOUNT_POINT\var\run\secrets\kubernetes.io\serviceaccount\`
## Resource Limits
Resource limits (disk, memory, cpu count) are applied to the job and are job wide.
For example, with a limit of 10MB set, the memory allocated for any HostProcess job object
will be capped at 10MB. This is the same behavior as other Windows container types.
These limits would be specified the same way they are currently for whatever orchestrator
or runtime is being used. The only difference is in the disk resource usage calculation
used for resource tracking due to the difference in how HostProcess containers are bootstrapped.
## Choosing a User Account ## Choosing a User Account
HostProcess containers support the ability to run as one of three supported Windows service accounts: As of 1.23, HostProcess containers support the ability to run as one of three supported Windows service accounts:
- **[LocalSystem](https://docs.microsoft.com/en-us/windows/win32/services/localsystem-account)** - **[LocalSystem](https://docs.microsoft.com/windows/win32/services/localsystem-account)**
- **[LocalService](https://docs.microsoft.com/en-us/windows/win32/services/localservice-account)** - **[LocalService](https://docs.microsoft.com/windows/win32/services/localservice-account)**
- **[NetworkService](https://docs.microsoft.com/en-us/windows/win32/services/networkservice-account)** - **[NetworkService](https://docs.microsoft.com/windows/win32/services/networkservice-account)**
You should select an appropriate Windows service account for each HostProcess You should select an appropriate Windows service account for each HostProcess
container, aiming to limit the degree of privileges so as to avoid accidental (or even container, aiming to limit the degree of privileges so as to avoid accidental (or even