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Update docs on virtual-kubelet.io (#754)

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* Update website content

* Add PodLifecycleHandler
This commit is contained in:
Ernest Wong
2019-09-03 10:52:23 -07:00
committed by Brian Goff
parent 2507f57f97
commit ee31118596
3 changed files with 49 additions and 57 deletions
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website/content/docs/providers.md
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@@ -26,69 +26,54 @@ Virtual Kubelet currently has a wide variety of providers:
## Adding new providers {#adding}
To add a new Virtual Kubelet provider, create a new directory for your provider in the [`providers`](https://github.com/virtual-kubelet/virtual-kubelet/tree/master/providers) directory.
To add a new Virtual Kubelet provider, create a new directory for your provider.
```shell
git clone https://github.com/virtual-kubelet/virtual-kubelet
cd virtual-kubelet
mkdir providers/my-provider
```
In that created directory, implement [`PodLifecycleHandler`](https://godoc.org/github.com/virtual-kubelet/virtual-kubelet/node#PodLifecycleHandler) interface in [Go](https://golang.org).
In that created directory, implement the [`Provider`](https://godoc.org/github.com/virtual-kubelet/virtual-kubelet/providers#Provider) interface in [Go](https://golang.org).
> For an example implementation of the Virtual Kubelet `Provider` interface, see the [Virtual Kubelet CRI Provider](https://github.com/virtual-kubelet/virtual-kubelet/tree/master/providers/cri), especially [`cri.go`](https://github.com/virtual-kubelet/virtual-kubelet/blob/master/providers/cri/cri.go).
> For an example implementation of the Virtual Kubelet `PodLifecycleHandler` interface, see the [Virtual Kubelet CRI Provider](https://github.com/virtual-kubelet/cri), especially [`cri.go`](https://github.com/virtual-kubelet/cri/blob/master/cri.go).
Each Virtual Kubelet provider can be configured using its own configuration file and environment variables.
You can see the list of required methods, with relevant descriptions of each method, below:
```go
// Provider contains the methods required to implement a Virtual Kubelet provider
type Provider interface {
// Takes a Kubernetes Pod and deploys it within the provider
CreatePod(ctx context.Context, pod *v1.Pod) error
// PodLifecycleHandler defines the interface used by the PodController to react
// to new and changed pods scheduled to the node that is being managed.
//
// Errors produced by these methods should implement an interface from
// github.com/virtual-kubelet/virtual-kubelet/errdefs package in order for the
// core logic to be able to understand the type of failure.
type PodLifecycleHandler interface {
// CreatePod takes a Kubernetes Pod and deploys it within the provider.
CreatePod(ctx context.Context, pod *corev1.Pod) error
// Takes a Kubernetes Pod and updates it within the provider
UpdatePod(ctx context.Context, pod *v1.Pod) error
// UpdatePod takes a Kubernetes Pod and updates it within the provider.
UpdatePod(ctx context.Context, pod *corev1.Pod) error
// Takes a Kubernetes Pod and deletes it from the provider
DeletePod(ctx context.Context, pod *v1.Pod) error
// DeletePod takes a Kubernetes Pod and deletes it from the provider.
DeletePod(ctx context.Context, pod *corev1.Pod) error
// Retrieves a pod by name from the provider (can be cached)
GetPod(ctx context.Context, namespace, name string) (*v1.Pod, error)
// GetPod retrieves a pod by name from the provider (can be cached).
// The Pod returned is expected to be immutable, and may be accessed
// concurrently outside of the calling goroutine. Therefore it is recommended
// to return a version after DeepCopy.
GetPod(ctx context.Context, namespace, name string) (*corev1.Pod, error)
// Retrieves the logs of a container by name from the provider
GetContainerLogs(ctx context.Context, namespace, podName, containerName string, tail int) (string, error)
// GetPodStatus retrieves the status of a pod by name from the provider.
// The PodStatus returned is expected to be immutable, and may be accessed
// concurrently outside of the calling goroutine. Therefore it is recommended
// to return a version after DeepCopy.
GetPodStatus(ctx context.Context, namespace, name string) (*corev1.PodStatus, error)
// Executes a command in a container in the pod, copying data between
// in/out/err and the container's stdin/stdout/stderr
ExecInContainer(name string, uid types.UID, container string, cmd []string, in io.Reader, out, err io.WriteCloser, tty bool, resize <-chan remotecommand.TerminalSize, timeout time.Duration) error
// Retrieves the status of a pod by name from the provider
GetPodStatus(ctx context.Context, namespace, name string) (*v1.PodStatus, error)
// Retrieves a list of all pods running on the provider (can be cached)
GetPods(context.Context) ([]*v1.Pod, error)
// Returns a resource list with the capacity constraints of the provider
Capacity(context.Context) v1.ResourceList
// Returns a list of conditions (Ready, OutOfDisk, etc), which is polled
// periodically to update the node status within Kubernetes
NodeConditions(context.Context) []v1.NodeCondition
// Returns a list of addresses for the node status within Kubernetes
NodeAddresses(context.Context) []v1.NodeAddress
// Returns NodeDaemonEndpoints for the node status within Kubernetes.
NodeDaemonEndpoints(context.Context) *v1.NodeDaemonEndpoints
// Returns the operating system the provider is for
OperatingSystem() string
// GetPods retrieves a list of all pods running on the provider (can be cached).
// The Pods returned are expected to be immutable, and may be accessed
// concurrently outside of the calling goroutine. Therefore it is recommended
// to return a version after DeepCopy.
GetPods(context.Context) ([]*corev1.Pod, error)
}
```
In addition to `Provider`, there's an optional [`PodMetricsProvider`](https://godoc.org/github.com/virtual-kubelet/virtual-kubelet/providers#PodMetricsProvider) interface that providers can implement to expose Kubernetes Pod stats:
In addition to `PodLifecycleHandler`, there's an optional [`PodMetricsProvider`](https://godoc.org/github.com/virtual-kubelet/virtual-kubelet/cmd/virtual-kubelet/internal/provider#PodMetricsProvider) interface that providers can implement to expose Kubernetes Pod stats:
```go
type PodMetricsProvider interface {
@@ -102,8 +87,6 @@ For a Virtual Kubelet provider to be considered viable, it must support the foll
1. It must conform to the current API provided by Virtual Kubelet (see [above](#adding))
1. It won't have access to the [Kubernetes API server](https://kubernetes.io/docs/concepts/overview/kubernetes-api/), so it must provide a well-defined callback mechanism for fetching data like [Secrets](https://kubernetes.io/docs/concepts/configuration/secret/) and [ConfigMaps](https://kubernetes.io/docs/tutorials/configuration/).
In addition to implementing the `Provider` interface in `providers/<your provider>`, you also need to add your provider to the [`providers/register`](https://github.com/virtual-kubelet/virtual-kubelet/tree/master/providers/register) directory, in `provider_<your provider>.go`. Current examples include [`provider_azure.go`](https://github.com/virtual-kubelet/virtual-kubelet/blob/master/providers/register/provider_azure.go) and [`provider_aws.go`](https://github.com/virtual-kubelet/virtual-kubelet/blob/master/providers/register/provider_aws.go), which you can use as templates.
## Documentation
No Virtual Kubelet provider is complete without solid documentation. We strongly recommend providing a README for your provider in its directory. The READMEs for the currently existing implementations can provide a blueprint.