Enable parallel image pulls

As of 1.27, Kubernetes added support for parallelizing image pulls but
this is not enabled by default.  This is especially useful in situations
where multiple images need to be downloaded to a host, but one of them
is particularly large.

charts/cluster-api-cluster-openstack/templates/workload.yaml

@@ -107,6 +107,16 @@ spec:
         path: {{ $file.path }}
         permissions: "0600"
       {{- end }}
+      - path: /etc/kubernetes/patches/kubeletconfiguration0+strategic.json
+        owner: "root:root"
+        permissions: "0644"
+        content: |
+            {
+              "apiVersion": "kubelet.config.k8s.io/v1beta1",
+              "kind": "KubeletConfiguration",
+              "serializeImagePulls": false,
+              "maxParallelImagePulls": 10,
+            }
       joinConfiguration:
         nodeRegistration:
           name: {{ "'{{ local_hostname }}'" }}
@@ -115,4 +125,6 @@ spec:
             node-labels: {{- include "openstack.nodelabels.workload" $context | nindent 14 }}
           taints:
             {{- include "openstack.taints.workload" $ | nindent 10 }}
+        patches:
+          directory: /etc/kubernetes/patches
 {{- end }}