Virtual Kubelet
Virtual Kubelet is an open source Kubernetes kubelet implementation that masquerades as a kubelet for the purposes of connecting Kubernetes to other APIs. This allows the nodes to be backed by other services like ACI, Hyper.sh, AWS, etc. This connector features a pluggable architecture and direct use of Kubernetes primitives, making it much easier to build on.
We invite the Kubernetes ecosystem to join us in empowering developers to build upon our base.
Please note this software is experimental and should not be used for anything resembling a production workload.
The best description is "Kubernetes API on top, programmable back."
Table of Contents
How It Works
The diagram below illustrates how Virtual-Kubelet works.
Usage
Deploy a Kubernetes cluster and make sure it's reachable.
Run the binary with your chosen provider:
./bin/virtual-kubelet --provider <your provider>
Now that the virtual-kubelet is deployed run kubectl get nodes
and you should see
a virtual-kubelet
node.
Command-Line Usage
virtual-kubelet implements the Kubelet interface with a pluggable
backend implementation allowing users to create kubernetes nodes without running the kubelet.
This allows users to schedule kubernetes workloads on nodes that aren't running Kubernetes.
Usage:
virtual-kubelet [flags]
virtual-kubelet [command]
Available Commands:
help Help about any command
version Show the version of the program
Flags:
-h, --help help for virtual-kubelet
--kubeconfig string config file (default is $HOME/.kube/config)
--namespace string kuberentes namespace (default is 'all')
--nodename string kubernetes node name (default "virtual-kubelet")
--os string Operating System (Linux/Windows) (default "Linux")
--provider string cloud provider
--provider-config string cloud provider configuration file
--taint string apply taint to node, making scheduling explicit
Use "virtual-kubelet [command] --help" for more information about a command.
Deploy as a Pod by Helm Chart
Run these commands to deploy the virtual kubelet which connects your Kubernetes cluster to Azure Container Instances. If you want to run the connector from the Azure command-line check out this.
RELEASE_NAME=virtual-kubelet
CHART_URL=https://github.com/virtual-kubelet/virtual-kubelet/raw/master/charts/virtual-kubelet-0.1.0.tgz
helm install "$CHART_URL" --name "$RELEASE_NAME" \
--set env.azureClientId=<YOUR-AZURECLIENTID-HERE>,env.azureClientKey=<YOUR-AZURECLIENTKEY-HERE>,env.azureTenantId=<YOUR-AZURETENANTID-HERE>,env.azureSubscriptionId=<YOUR-AZURESUBSCRIPTIONID-HERE>,env.aciResourceGroup=<YOUR-ACIRESOURCEGROUP-HERE>,env.nodeName=<YOUR-NODE-NAME>, env.nodeOsType=<Linux|Windows>,env.nodeTaint=<YOUR-NODE-TAINT>
Providers
This project features a pluggable provider interface developers can implement that defines the actions of a typical kubelet.
This enables on-demand and nearly instantaneous container compute, orchestrated by Kubernetes, without having VM infrastructure to manage and while still leveraging the portable Kubernetes API.
Each provider may have its own configuration file, and required environmental variables.
Azure Container Instances Provider
The Azure Container Instances Provider allows you to utilize both typical pods on VMs and Azure Container instances simultaneously in the same Kubernetes cluster.
./bin/virtual-kubelet --provider azure
Environment Variables
ACI_RESOURCE_GROUP
must be set to the name of a valid Azure resource group where your
ACI workload will be run.
ACI_REGION
must be set to the name of the region your ACI_RESOURCE_GROUP
was created.
Configuration File
The Azure connector can use a configuration file specified by the --provider-config
flag.
The config file is in TOML format, and an example lives in providers/azure/example.toml
.
Hyper.sh Provider
The Hyper.sh Provider allows Kubernetes clusters to deploy Hyper.sh containers and manage both typical pods on VMs and Hyper.sh containers in the same Kubernetes cluster.
./bin/virtual-kubelet --provider hyper
Adding a New Provider via the Provider Interface
The structure we chose allows you to have all the power of the Kubernetes API on top with a pluggable interface.
Create a new directory for your provider under providers
and implement the
following interface. Then add your new provider under the others in the
vkubelet/provider.go
file.
// Provider contains the methods required to implement a virtual-kubelet provider.
type Provider interface {
// CreatePod takes a Kubernetes Pod and deploys it within the provider.
CreatePod(pod *v1.Pod) error
// UpdatePod takes a Kubernetes Pod and updates it within the provider.
UpdatePod(pod *v1.Pod) error
// DeletePod takes a Kubernetes Pod and deletes it from the provider.
DeletePod(pod *v1.Pod) error
// GetPod retrieves a pod by name from the provider (can be cached).
GetPod(namespace, name string) (*v1.Pod, error)
// GetPodStatus retrievesthe status of a pod by name from the provider.
GetPodStatus(namespace, name string) (*v1.PodStatus, error)
// GetPods retrieves a list of all pods running on the provider (can be cached).
GetPods() ([]*v1.Pod, error)
// Capacity returns a resource list with the capacity constraints of the provider.
Capacity() v1.ResourceList
// NodeConditions returns a list of conditions (Ready, OutOfDisk, etc), which is polled periodically to update the node status
// within Kuberentes.
NodeConditions() []v1.NodeCondition
// OperatingSystem returns the operating system the provider is for.
OperatingSystem() string
}
Testing
Running the unit tests locally is as simple as make test
.
Testing the Azure Provider Client
The unit tests for the azure
provider require a credentials.json
file exist in the root of this directory or that you have AZURE_AUTH_LOCATION
set to a credentials file.
You can generate this file by following the instructions listed in the README for that package.
Contributing
This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.
When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.
This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [email protected] with any additional questions or comments.