Add support to set allocation_pools for subnet

This commit adds API that allows users to set `allocations_pools` in the
subnet created by CAPO. This allows the users to restrict the IP address
ranges that will be allocated automatically by OpenStack when creating
Machines.

Users can utilize this to reserve addresses for VIPs (virtual IPs) or
special nodes that will have predefined addresses and will be created
later.

Author: dulek

api/v1alpha6/conversion.go

@@ -232,6 +232,11 @@ var v1alpha8OpenStackClusterRestorer = conversion.RestorerFor[*infrav1.OpenStack
 		},
 		restorev1alpha8ClusterStatus,
 	),
+	"managedSubnets": conversion.UnconditionalFieldRestorer(
+		func(c *infrav1.OpenStackCluster) *[]infrav1.SubnetSpec {
+			return &c.Spec.ManagedSubnets
+		},
+	),
 }
 
 func (r *OpenStackCluster) ConvertTo(dstRaw ctrlconversion.Hub) error {
@@ -322,6 +327,11 @@ var v1alpha8OpenStackClusterTemplateRestorer = conversion.RestorerFor[*infrav1.O
 		},
 		restorev1alpha8ManagedSecurityGroups,
 	),
+	"managedSubnets": conversion.UnconditionalFieldRestorer(
+		func(c *infrav1.OpenStackClusterTemplate) *[]infrav1.SubnetSpec {
+			return &c.Spec.Template.Spec.ManagedSubnets
+		},
+	),
 }
 
 func (r *OpenStackClusterTemplate) ConvertTo(dstRaw ctrlconversion.Hub) error {

api/v1alpha6/conversion_test.go

@@ -142,6 +142,19 @@ func TestFuzzyConversion(t *testing.T) {
 					spec.CIDR = c.RandString()
 				}
 			},
+
+			func(pool *infrav1.AllocationPool, c fuzz.Continue) {
+				c.FuzzNoCustom(pool)
+
+				// Start and End are required properties, let's make sure both are set
+				for pool.Start == "" {
+					pool.Start = c.RandString()
+				}
+
+				for pool.End == "" {
+					pool.End = c.RandString()
+				}
+			},
 		}
 	}
 

api/v1alpha7/conversion_test.go

@@ -110,6 +110,19 @@ func TestFuzzyConversion(t *testing.T) {
 					spec.CIDR = c.RandString()
 				}
 			},
+
+			func(pool *infrav1.AllocationPool, c fuzz.Continue) {
+				c.FuzzNoCustom(pool)
+
+				// Start and End are required properties, let's make sure both are set
+				for pool.Start == "" {
+					pool.Start = c.RandString()
+				}
+
+				for pool.End == "" {
+					pool.End = c.RandString()
+				}
+			},
 		}
 	}
 

api/v1alpha8/types.go

@@ -92,9 +92,25 @@ type SubnetSpec struct {
 	// This field is required when defining a subnet.
 	// +required
 	CIDR string `json:"cidr"`
+
 	// DNSNameservers holds a list of DNS server addresses that will be provided when creating
 	// the subnet. These addresses need to have the same IP version as CIDR.
 	DNSNameservers []string `json:"dnsNameservers,omitempty"`
+
+	// AllocationPools is an array of AllocationPool objects that will be applied to OpenStack Subnet being created.
+	// If set, OpenStack will only allocate these IPs for Machines. It will still be possible to create ports from
+	// outside of these ranges manually.
+	AllocationPools []AllocationPool `json:"allocationPools,omitempty"`
+}
+
+type AllocationPool struct {
+	// Start represents the start of the AllocationPool, that is the lowest IP of the pool.
+	// +required
+	Start string `json:"start"`
+
+	// End represents the end of the AlloctionPool, that is the highest IP of the pool.
+	// +required
+	End string `json:"end"`
 }
 
 type PortOpts struct {

api/v1alpha8/zz_generated.deepcopy.go

@@ -5537,6 +5537,26 @@ spec:
                   subnet is supported. If you leave this empty, no network will be created.
                 items:
                   properties:
+                    allocationPools:
+                      description: |-
+                        AllocationPools is an array of AllocationPool objects that will be applied to OpenStack Subnet being created.
+                        If set, OpenStack will only allocate these IPs for Machines. It will still be possible to create ports from
+                        outside of these ranges manually.
+                      items:
+                        properties:
+                          end:
+                            description: End represents the end of the AlloctionPool,
+                              that is the highest IP of the pool.
+                            type: string
+                          start:
+                            description: Start represents the start of the AllocationPool,
+                              that is the lowest IP of the pool.
+                            type: string
+                        required:
+                        - end
+                        - start
+                        type: object
+                      type: array
                     cidr:
                       description: |-
                         CIDR is representing the IP address range used to create the subnet, e.g. 10.0.0.0/24.

config/crd/bases/infrastructure.cluster.x-k8s.io_openstackclusters.yaml

@@ -2972,6 +2972,27 @@ spec:
                           subnet is supported. If you leave this empty, no network will be created.
                         items:
                           properties:
+                            allocationPools:
+                              description: |-
+                                AllocationPools is an array of AllocationPool objects that will be applied to OpenStack Subnet being created.
+                                If set, OpenStack will only allocate these IPs for Machines. It will still be possible to create ports from
+                                outside of these ranges manually.
+                              items:
+                                properties:
+                                  end:
+                                    description: End represents the end of the AlloctionPool,
+                                      that is the highest IP of the pool.
+                                    type: string
+                                  start:
+                                    description: Start represents the start of the
+                                      AllocationPool, that is the lowest IP of the
+                                      pool.
+                                    type: string
+                                required:
+                                - end
+                                - start
+                                type: object
+                              type: array
                             cidr:
                               description: |-
                                 CIDR is representing the IP address range used to create the subnet, e.g. 10.0.0.0/24.

config/crd/bases/infrastructure.cluster.x-k8s.io_openstackclustertemplates.yaml

@@ -210,6 +210,10 @@ In v1alpha8, this will be automatically converted to:
 
 Please note that currently `managedSubnets` can only hold one element.
 
+#### Addition of allocationPools
+
+In v1alpha8, an `AllocationPools` property is introduced to `OpenStackCluster.Spec.ManagedSubnets`. When specified, OpenStack subnet created by CAPO will have the given values set as the `allocation_pools` property. This allows users to make sure OpenStack will not allocate some IP ranges in the subnet automatically. If the subnet is precreated and configured, CAPO will ignore `AllocationPools` property.
+
 #### Change to managedSecurityGroups
 
 The field `managedSecurityGroups` is now a pointer to a `ManagedSecurityGroups` object rather than a boolean.

docs/book/src/topics/crd-changes/v1alpha7-to-v1alpha8.md

@@ -256,6 +256,10 @@ func (s *Service) createSubnet(openStackCluster *infrav1.OpenStackCluster, clust
 		Description:    names.GetDescription(clusterName),
 	}
 
+	for _, pool := range openStackCluster.Spec.ManagedSubnets[0].AllocationPools {
+		opts.AllocationPools = append(opts.AllocationPools, subnets.AllocationPool{Start: pool.Start, End: pool.End})
+	}
+
 	subnet, err := s.client.CreateSubnet(opts)
 	if err != nil {
 		record.Warnf(openStackCluster, "FailedCreateSubnet", "Failed to create subnet %s: %v", name, err)