tests: capture k3s startup failures

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

Author: crazy-max

tests/helpers/k3d.go

@@ -39,6 +39,7 @@ func NewK3dServer(ctx context.Context, cfg *integration.BackendConfig, dockerAdd
 	args := []string{
 		"cluster", "create", clusterName,
 		"--wait",
+		"--k3s-arg=--debug@server:0",
 	}
 	if image := KubernetesK3sImage(); image != "" {
 		args = append(args, "--image="+image)

tests/helpers/kubernetes_diagnostics.go

@@ -86,6 +86,7 @@ func appendK3sServerDiagnostics(ctx context.Context, buf *bytes.Buffer, clusterN
 		appendCommandOutput(ctx, buf, "docker exec "+nodeName+" cgroup", "docker", []string{"exec", nodeName, "sh", "-c", "cat /proc/1/cgroup && echo && mount | grep cgroup"}, []string{"DOCKER_CONTEXT=" + dockerContext})
 		appendCommandOutput(ctx, buf, "docker exec "+nodeName+" env", "docker", []string{"exec", nodeName, "sh", "-c", "env | sort"}, []string{"DOCKER_CONTEXT=" + dockerContext})
 		appendCommandOutput(ctx, buf, "docker exec "+nodeName+" entrypoint", "docker", []string{"exec", nodeName, "sh", "-c", "sed -n '1,200p' /bin/k3d-entrypoint.sh"}, []string{"DOCKER_CONTEXT=" + dockerContext})
+		appendCommandOutput(ctx, buf, "docker exec "+nodeName+" entrypoint logs", "docker", []string{"exec", nodeName, "sh", "-c", "for f in /var/log/k3d-entrypoints_*.log; do if [ -f \"$f\" ]; then echo \"== $f ==\"; tail -n 200 \"$f\"; echo; fi; done"}, []string{"DOCKER_CONTEXT=" + dockerContext})
 		appendCommandOutput(ctx, buf, "docker exec "+nodeName+" k3s files", "docker", []string{"exec", nodeName, "sh", "-c", "find /var/lib/rancher/k3s -maxdepth 3 -type f 2>/dev/null | sort"}, []string{"DOCKER_CONTEXT=" + dockerContext})
 		appendCommandOutput(ctx, buf, "docker exec "+nodeName+" k3s logs", "docker", []string{"exec", nodeName, "sh", "-c", "for f in /var/log/k3s.log /var/lib/rancher/k3s/agent/containerd/containerd.log /var/lib/rancher/k3s/server/logs/*; do if [ -f \"$f\" ]; then echo \"== $f ==\"; tail -n 200 \"$f\"; echo; fi; done"}, []string{"DOCKER_CONTEXT=" + dockerContext})
 		appendCommandOutput(ctx, buf, "docker exec "+nodeName+" kubectl get pods", "docker", []string{"exec", nodeName, "kubectl", "get", "pods", "-A", "-o", "wide"}, []string{"DOCKER_CONTEXT=" + dockerContext})