[suggestion] Allow to add new labels to the node

[cmoulliard]

Suggestion

The kind go project allows to set additonal labels to a node using the type field

// https://github.com/kubernetes-sigs/kind/blob/296749aa2de8577f6865e4db1870d2566a28d14b/pkg/apis/config/v1alpha4/types.go#L108

// Labels are the labels with which the respective node will be labeled
Labels map[string]string `yaml:"labels,omitempty" json:"labels,omitempty"`

that a user can define par of the kube config file

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  image: "kindest/node:v1.31.4"
  labels:
    ingress-ready: "true"
  extraPortMappings:
  - containerPort: 443
    hostPort: 8443
    protocol: TCP
...

that the kind go project will render in the template using the field

// https://github.com/kubernetes-sigs/kind/blob/f96632a3c84686f5cf322e1d5f0201b02ca324e9/pkg/cluster/internal/kubeadm/config.go#L243-L248
  kubeletExtraArgs:
    node-ip: "{{ .NodeAddress }}"
    provider-id: "kind://{{.NodeProvider}}/{{.ClusterName}}/{{.NodeName}}"
    node-labels: "{{ .NodeLabels }}"

Such a feature is not supported by this project and is blocking by example the deployment of the ingress controller where a new label has been declared part of the nodeSelector section

// https://github.com/kubernetes/ingress-nginx/blob/main/deploy/static/provider/kind/deploy.yaml#L508
 nodeSelector:
    ingress-ready: "true"
    kubernetes.io/os: linux

[dajudge]

Hi @cmoulliard! Thank you for your input!

Would maybe something a long these lines solve the problem you describe?

kindcontainer/src/test/java/com/dajudge/kindcontainer/kubectl/KubectlLabelFluentTest.java

Line 38 in cc646b8

return container.withKubectl(kubectl -> kubectl.label

[cmoulliard]

Some changes are required within the existing code:

• Add a new field to allow a user to pass using a property the labels to be added the Node
• Update the kubeadm-1.[21,24].0.yaml files to allow to pass the labels part of the following field

  kubeletExtraArgs:
    fail-swap-on: "false"
    node-ip: {{ .NodeIp }}
    node-labels: {{ .NodeLabels }}
    provider-id: kind://docker/kind/kindcontainer-control-plane

• Add labels to the list of the params

// https://github.com/dajudge/kindcontainer/blob/f89039b84c56ffffbd9deb0d3d05a5a3022c1d51/src/main/java/com/dajudge/kindcontainer/KindContainer.java#L206

        final Map<String, String> params = new HashMap<String, String>() {{
            put(".NodeIp", containerInternalIpAddress);
            put(".NodeLabels", nodeLabels);
..

Note: We will have also to adapt this method which until now only accept a Map<String, String> and only a key and value and not a list a values = labels !!

//     private static String template(String string, final Map<String, String> replacements) {
        return replacements.entrySet().stream()
                .map(r -> ((Function<String, String>) (s -> s.replace("{{ " + r.getKey() + " }}", r.getValue()))))
                .reduce(Function.identity(), Function::andThen)
                .apply(string);
    }

[cmoulliard]

We could also patch the node created within the container too as you do here to untain:

// https://github.com/dajudge/kindcontainer/blob/f89039b84c56ffffbd9deb0d3d05a5a3022c1d51/src/main/java/com/dajudge/kindcontainer/KindContainer.java#L229

    private void untaintNode() {
        client().v1().nodes().list().getItems().forEach(node -> {
            asList("master", "control-plane").forEach(role -> {
                final String key = format("node-role.kubernetes.io/%s", role);
                final String effect = "NoSchedule";
                final String removeTaint = String.format("%s:%s-", key, effect);
                if (hasTaint(node, key, null, effect)) {
                    try {
                        kubectl("taint", "node", node.getMetadata().getName(), removeTaint);
                    } catch (final IOException | InterruptedException e) {
                        throw new RuntimeException("Failed to untaint node", e);
                    }
                }
            });
        });
    }

[dajudge]

The described use case is already supported through the post-startup kubectl API, without modifying the kubeadm templates:

new KindContainer<>()
        .withKubectl(kubectl -> kubectl.label
                .with("ingress-ready", "true")
                .run("node", "kind"))
        .withKubectl(kubectl -> {
            // Install ingress-nginx here
        });

The node is labelled before subsequent startup callbacks install workloads that select it. A dedicated kubeadm-template option would duplicate this existing functionality, so I’m closing the issue as already supported.