Bash
An example of deploying and managing Virtual Servers using programmatic access to the Kubernetes REST API with Bash.
Overview
Follow along by pulling the example script from CoreWeave's GitHub.
In this example, the curl
and jq
tools are used to perform the following actions via the Kubernetes REST API using Bash:
- Create a CoreWeave Virtual Server, which:
- Runs Ubuntu 20.04
- Has 2 CPUs
- Has 2Gi of memory
- List the created Virtual Server.
- Delete the created Virtual Server.
Using curl
and jq
to deploy a Virtual Server
This script makes calls to two different API endpoints separately:
The Kubevirt endpoint
Kubevirt is an open-source project that allows running virtual systems on the Kubernetes cluster. The script defines and leverages the following functions to call to the Kubevirt API:
VM
start_vm()
- Starts a Virtual Machine and creates a Virtual Machine Instance (VMI)stop_vm()
- Stops the Virtual Machine, then deletes the Virtual Machine Instance (VMI)list_vm()
- Lists all the Virtual Machines (VMs) in the namespaceget_vm()
- Prints formatted JSON details about the Virtual Machine (requiresjq)
VMI
list_vmi()
- Lists all the Virtual Machine Instances (VMIs) in the designated namespaceget_vmi()
- Prints formatted JSON details about the Virtual Machine Instance (VMI)
The Virtual Server endpoint
The Virtual Server endpoint is a Kubernetes Custom Resource that allows deploying a virtual system and interacting with Kubevirt with ease.
Functions calling the Virtual Server API
The Bash script defines and leverages the following functions to call the Virtual Server API:
create_vs()
- Creates a Virtual Server (VS)delete_vs()
- Deletes a Virtual Server (VS)list_vs()
- Lists of all the Virtual Servers (VS) in the designated namespaceget_vs()
- Prints formatted JSON details about the Virtual Server (requiresjq
)wait_until_vs_status()
- Loops until the expected condition of the Virtual Server (VS) is met
Installation
Before invoking the script, the jq
and curl
commands must be installed and available from the PATH
.
Environment variables
In invoking this script, TOKEN
and NAMESPACE
are exported as environment variables. The value of NAMESPACE
should be set to the desired namespace. The value of TOKEN
should be replaced with the value of 'token:'
generated in the kubeconfig
file.
Run
The script is invoked using the following command and environment variable exports:
TOKEN=<token> NAMESPACE=<namespace> ./run.sh
The latest resource details, such as statuses and conditions, are available in the Virtual Servers reference API.
The general description of the Kubernetes RESTful API is available in the official documentation of the Kubernetes API Overview.
The basic concepts of the API are described in the official documentation of the Kubernetes API Concepts.
The Kubevirt Python client, kubevirt-py, can list all of the Kubevirt RESTful API endpoints for both VMs and VMIs.