Container Resource Upsync Plugin

The container resource upsync plugin annotates vcluster pods with any container resource constraints found on the host cluster, but not the virtual cluster. This is to account for the scenario where a Limit Range in the host cluster mutates the physical pod, but the changes are not reflected in the virtual pod.

For more information how to develop plugins in vcluster, please refer to the official vcluster docs.

Using the Plugin

To use the plugin, create a new vcluster with the plugin.yaml:

# Use public plugin.yaml
vcluster create my-vcluster -n my-vcluster -f https://raw.githubusercontent.com/spectrocloud-labs/vcluster-container-resource-upsync-plugin/main/plugin.yaml

Building the Plugin

To build the plugin image and push it to the registry, run:

# Build
docker build . -t my-repo/my-plugin:0.0.1

# Push
docker push my-repo/my-plugin:0.0.1

Then exchange the image in the plugin.yaml.

Development

General vcluster plugin project structure:

.
├── go.mod              # Go module definition
├── go.sum
├── devspace.yaml       # Development environment definition
├── devspace_start.sh   # Development entrypoint script
├── Dockerfile          # Production Dockerfile 
├── Dockerfile.dev      # Development Dockerfile
├── main.go             # Go Entrypoint
├── plugin.yaml         # Plugin Helm Values
├── syncers/            # Plugin Syncers
└── manifests/          # Additional plugin resources

Before starting to develop, make sure you have installed the following tools on your computer:

• docker
• kubectl with a valid kube context configured
• helm, which is used to deploy vcluster and the plugin
• vcluster CLI v0.6.0 or higher
• DevSpace, which is used to spin up a development environment

If you want to develop within a remote Kubernetes cluster (as opposed to docker-desktop or minikube), make sure to exchange PLUGIN_IMAGE in the devspace.yaml with a valid registry path you can push to.

After successfully setting up the tools, start the development environment with:

devspace dev -n vcluster

After a while a terminal should show up with additional instructions. Enter the following command to start the plugin:

go run -mod vendor main.go

The output should look something like this:

I0124 11:20:14.702799    4185 logr.go:249] plugin: Try creating context...
I0124 11:20:14.730044    4185 logr.go:249] plugin: Waiting for vcluster to become leader...
I0124 11:20:14.731097    4185 logr.go:249] plugin: Starting syncers...
[...]
I0124 11:20:15.957331    4185 logr.go:249] plugin: Successfully started plugin.

You can now change a file locally in your IDE and then restart the command in the terminal to apply the changes to the plugin.

Delete the development environment with:

devspace purge -n vcluster