Merge pull request #15369 from vespa-engine/hakonhall/introduce-node-ip-address-pool

Introduce node IP address pool

20 files changed, 302 insertions, 98 deletions

diff --git a/athenz-identity-provider-service/src/test/java/com/yahoo/vespa/hosted/athenz/instanceproviderservice/identitydocument/IdentityDocumentGeneratorTest.java b/athenz-identity-provider-service/src/test/java/com/yahoo/vespa/hosted/athenz/instanceproviderservice/identitydocument/IdentityDocumentGeneratorTest.java
index edda5593e79..0a757b5b17b 100644
--- a/athenz-identity-provider-service/src/test/java/com/yahoo/vespa/hosted/athenz/instanceproviderservice/identitydocument/IdentityDocumentGeneratorTest.java
+++ b/athenz-identity-provider-service/src/test/java/com/yahoo/vespa/hosted/athenz/instanceproviderservice/identitydocument/IdentityDocumentGeneratorTest.java
@@ -57,7 +57,7 @@ public class IdentityDocumentGeneratorTest {
                                                Generation.initial(),
                                                false);
         Node parentNode = Node.create("ostkid",
-                                      new IP.Config(Set.of("127.0.0.1"), Set.of()),
+                                      IP.Config.ofEmptyPool(Set.of("127.0.0.1")),
                                       parentHostname,
                                       new MockNodeFlavors().getFlavorOrThrow("default"),
                                       NodeType.host).build();
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/Node.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/Node.java
index 298404256b9..d0ee6229428 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/Node.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/Node.java
@@ -55,7 +55,7 @@ public final class Node implements Nodelike {
     /** Creates a node builder in the initial state (reserved) */
     public static Node.Builder createDockerNode(Set<String> ipAddresses, String hostname, String parentHostname, NodeResources resources, NodeType type) {
         return new Node.Builder("fake-" + hostname, hostname, new Flavor(resources), State.reserved, type)
-                .ipConfig(ipAddresses, Set.of())
+                .ipConfig(IP.Config.ofEmptyPool(ipAddresses))
                 .parentHostname(parentHostname);
     }
 
@@ -573,8 +573,8 @@ public final class Node implements Nodelike {
             return this;
         }
 
-        public Builder ipConfig(Set<String> primary, Set<String> pool) {
-            this.ipConfig = new IP.Config(primary, pool);
+        public Builder ipConfigWithEmptyPool(Set<String> primary) {
+            this.ipConfig = IP.Config.ofEmptyPool(primary);
             return this;
         }
 
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/CapacityChecker.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/CapacityChecker.java
index e5202dfd3c0..6094b497fff 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/CapacityChecker.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/maintenance/CapacityChecker.java
@@ -135,12 +135,12 @@ public class CapacityChecker {
         for (var host : hosts) {
             NodeResources hostResources = host.flavor().resources();
             int occupiedIps = 0;
-            Set<String> ipPool = host.ipConfig().pool().asSet();
+            Set<String> ipPool = host.ipConfig().pool().getIpSet();
             for (var child : nodeChildren.get(host)) {
                 hostResources = hostResources.subtract(child.resources().justNumbers());
                 occupiedIps += child.ipConfig().primary().stream().filter(ipPool::contains).count();
             }
-            availableResources.put(host, new AllocationResources(hostResources, host.ipConfig().pool().asSet().size() - occupiedIps));
+            availableResources.put(host, new AllocationResources(hostResources, host.ipConfig().pool().getIpSet().size() - occupiedIps));
         }
 
         return availableResources;
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/Address.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/Address.java
new file mode 100644
index 00000000000..bdef06f1070
--- /dev/null
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/Address.java
@@ -0,0 +1,49 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.provision.node;
+
+import java.util.Objects;
+
+/**
+ * Address info about a container that might run on a host.
+ *
+ * @author hakon
+ */
+public class Address {
+    private final String hostname;
+
+    public Address(String hostname) {
+        this.hostname = validateHostname(hostname, "hostname");
+    }
+
+    public String hostname() {
+        return hostname;
+    }
+
+    @Override
+    public String toString() {
+        return "Address{" +
+                "hostname='" + hostname + '\'' +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Address address = (Address) o;
+        return hostname.equals(address.hostname);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(hostname);
+    }
+
+    private String validateHostname(String value, String name) {
+        Objects.requireNonNull(value, name + " cannot be null");
+        if (value.isEmpty()) {
+            throw new IllegalArgumentException(name + " cannot be empty");
+        }
+        return value;
+    }
+}
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/IP.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/IP.java
index 955936931be..41d6c1e5425 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/IP.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/IP.java
@@ -60,15 +60,29 @@ public class IP {
     /** IP configuration of a node */
     public static class Config {
 
-        public static final Config EMPTY = new Config(Set.of(), Set.of());
+        public static final Config EMPTY = Config.ofEmptyPool(Set.of());
 
         private final Set<String> primary;
         private final Pool pool;
 
-        /** DO NOT USE in non-test code. Public for serialization purposes. */
+        public static Config ofEmptyPool(Set<String> primary) {
+            return new Config(primary, Set.of(), List.of());
+        }
+
+        public static Config of(Set<String> primary, Set<String> ipPool, List<Address> addressPool) {
+            return new Config(primary, ipPool, addressPool);
+        }
+
+        /** LEGACY TEST CONSTRUCTOR - use of() variants and/or the with- methods. */
         public Config(Set<String> primary, Set<String> pool) {
+            this(primary, pool, List.of());
+        }
+
+        /** DO NOT USE: Public for NodeSerializer. */
+        public Config(Set<String> primary, Set<String> pool, List<Address> addresses) {
             this.primary = ImmutableSet.copyOf(Objects.requireNonNull(primary, "primary must be non-null"));
-            this.pool = Pool.of(Objects.requireNonNull(pool, "pool must be non-null"));
+            this.pool = Pool.of(Objects.requireNonNull(pool, "pool must be non-null"),
+                                Objects.requireNonNull(addresses, "addresses must be non-null"));
         }
 
         /** The primary addresses of this. These addresses are used when communicating with the node itself */
@@ -82,13 +96,13 @@ public class IP {
         }
 
         /** Returns a copy of this with pool set to given value */
-        public Config with(Pool pool) {
-            return new Config(primary, pool.asSet());
+        public Config withPool(Pool pool) {
+            return new Config(primary, pool.getIpSet(), pool.getAddressList());
         }
 
         /** Returns a copy of this with pool set to given value */
-        public Config with(Set<String> primary) {
-            return new Config(primary, pool.asSet());
+        public Config withPrimary(Set<String> primary) {
+            return new Config(primary, pool.getIpSet(), pool.getAddressList());
         }
 
         @Override
@@ -107,7 +121,7 @@ public class IP {
 
         @Override
         public String toString() {
-            return String.format("ip config primary=%s pool=%s", primary, pool.asSet());
+            return String.format("ip config primary=%s pool=%s", primary, pool.getIpSet());
         }
 
         /**
@@ -124,8 +138,8 @@ public class IP {
                     var addresses = new HashSet<>(node.ipConfig().primary());
                     var otherAddresses = new HashSet<>(other.ipConfig().primary());
                     if (node.type().isHost()) { // Addresses of a host can never overlap with any other nodes
-                        addresses.addAll(node.ipConfig().pool().asSet());
-                        otherAddresses.addAll(other.ipConfig().pool().asSet());
+                        addresses.addAll(node.ipConfig().pool().getIpSet());
+                        otherAddresses.addAll(other.ipConfig().pool().getIpSet());
                     }
                     otherAddresses.retainAll(addresses);
                     if (!otherAddresses.isEmpty())
@@ -157,18 +171,18 @@ public class IP {
     }
 
     /** A list of IP addresses and their protocol */
-    public static class Addresses {
+    public static class IpAddresses {
 
-        private final Set<String> addresses;
+        private final Set<String> ipAddresses;
         private final Protocol protocol;
 
-        private Addresses(Set<String> addresses, Protocol protocol) {
-            this.addresses = ImmutableSet.copyOf(Objects.requireNonNull(addresses, "addresses must be non-null"));
+        private IpAddresses(Set<String> ipAddresses, Protocol protocol) {
+            this.ipAddresses = ImmutableSet.copyOf(Objects.requireNonNull(ipAddresses, "addresses must be non-null"));
             this.protocol = Objects.requireNonNull(protocol, "type must be non-null");
         }
 
         public Set<String> asSet() {
-            return addresses;
+            return ipAddresses;
         }
 
         /** The protocol of addresses in this */
@@ -177,20 +191,20 @@ public class IP {
         }
 
         /** Create addresses of the given set */
-        private static Addresses of(Set<String> addresses) {
+        private static IpAddresses of(Set<String> addresses) {
             long ipv6AddrCount = addresses.stream().filter(IP::isV6).count();
             if (ipv6AddrCount == addresses.size()) { // IPv6-only
-                return new Addresses(addresses, Protocol.ipv6);
+                return new IpAddresses(addresses, Protocol.ipv6);
             }
 
             long ipv4AddrCount = addresses.stream().filter(IP::isV4).count();
             if (ipv4AddrCount == addresses.size()) { // IPv4-only
-                return new Addresses(addresses, Protocol.ipv4);
+                return new IpAddresses(addresses, Protocol.ipv4);
             }
 
             // If we're dual-stacked, we must must have an equal number of addresses of each protocol.
             if (ipv4AddrCount == ipv6AddrCount) {
-                return new Addresses(addresses, Protocol.dualStack);
+                return new IpAddresses(addresses, Protocol.dualStack);
             }
 
             throw new IllegalArgumentException(String.format("Dual-stacked IP address list must have an " +
@@ -208,15 +222,28 @@ public class IP {
     }
 
     /**
-     * A pool of IP addresses from which an allocation can be made.
+     * A pool of addresses from which an allocation can be made.
      *
      * Addresses in this are available for use by Docker containers
      */
     public static class Pool {
 
-        private final Addresses addresses;
+        private final IpAddresses ipAddresses;
+        private final List<Address> addresses;
 
-        private Pool(Addresses addresses) {
+        /** Creates an empty pool. */
+        public static Pool of() {
+            return of(Set.of(), List.of());
+        }
+
+        /** Create a new pool containing given ipAddresses */
+        public static Pool of(Set<String> ipAddresses, List<Address> addresses) {
+            IpAddresses ips = IpAddresses.of(ipAddresses);
+            return new Pool(ips, addresses);
+        }
+
+        private Pool(IpAddresses ipAddresses, List<Address> addresses) {
+            this.ipAddresses = Objects.requireNonNull(ipAddresses, "ipAddresses must be non-null");
             this.addresses = Objects.requireNonNull(addresses, "addresses must be non-null");
         }
 
@@ -227,6 +254,12 @@ public class IP {
          * @return an allocation from the pool, if any can be made
          */
         public Optional<Allocation> findAllocation(LockedNodeList nodes, NameResolver resolver) {
+            if (ipAddresses.protocol == IpAddresses.Protocol.ipv4) {
+                return findUnused(nodes).stream()
+                        .findFirst()
+                        .map(addr -> Allocation.ofIpv4(addr, resolver));
+            }
+
             var unusedAddresses = findUnused(nodes);
             var allocation = unusedAddresses.stream()
                                             .filter(IP::isV6)
@@ -248,64 +281,47 @@ public class IP {
          * @param nodes a list of all nodes in the repository
          */
         public Set<String> findUnused(NodeList nodes) {
-            var unusedAddresses = new LinkedHashSet<>(asSet());
-            nodes.matching(node -> node.ipConfig().primary().stream().anyMatch(ip -> asSet().contains(ip)))
+            var unusedAddresses = new LinkedHashSet<>(getIpSet());
+            nodes.matching(node -> node.ipConfig().primary().stream().anyMatch(ip -> getIpSet().contains(ip)))
                  .forEach(node -> unusedAddresses.removeAll(node.ipConfig().primary()));
             return Collections.unmodifiableSet(unusedAddresses);
         }
 
-        public Set<String> asSet() {
-            return addresses.asSet();
+        public IpAddresses.Protocol getProtocol() {
+            return ipAddresses.protocol;
         }
 
-        public boolean isEmpty() {
-            return asSet().isEmpty();
+        public Set<String> getIpSet() {
+            return ipAddresses.asSet();
         }
 
-        @Override
-        public boolean equals(Object o) {
-            if (this == o) return true;
-            if (o == null || getClass() != o.getClass()) return false;
-            Pool that = (Pool) o;
-            return Objects.equals(addresses, that.addresses);
+        public List<Address> getAddressList() {
+            return addresses;
         }
 
-        @Override
-        public int hashCode() {
-            return Objects.hash(addresses);
+        public boolean isEmpty() {
+            return getIpSet().isEmpty();
         }
 
-        /** Create a new pool containing given ipAddresses */
-        public static Pool of(Set<String> ipAddresses) {
-            var addresses = Addresses.of(ipAddresses);
-            if (addresses.protocol() == Addresses.Protocol.ipv4) {
-                return new Ipv4Pool(addresses);
-            }
-            return new Pool(addresses);
+        public Pool withIpAddresses(Set<String> ipAddresses) {
+            return Pool.of(ipAddresses, addresses);
         }
 
-        /** Validates and returns the given IP address pool */
-        public static Set<String> require(Set<String> pool) {
-            return of(pool).asSet();
+        public Pool withAddresses(List<Address> addresses) {
+            return Pool.of(ipAddresses.ipAddresses, addresses);
         }
 
-    }
-
-    /** A pool of IPv4-only addresses from which an allocation can be made. */
-    public static class Ipv4Pool extends Pool {
-
-        private Ipv4Pool(Addresses addresses) {
-            super(addresses);
-            if (addresses.protocol() != Addresses.Protocol.ipv4) {
-                throw new IllegalArgumentException("Protocol of addresses must be " + Addresses.Protocol.ipv4);
-            }
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Pool that = (Pool) o;
+            return Objects.equals(ipAddresses, that.ipAddresses);
         }
 
         @Override
-        public Optional<Allocation> findAllocation(LockedNodeList nodes, NameResolver resolver) {
-            return findUnused(nodes).stream()
-                                    .findFirst()
-                                    .map(addr -> Allocation.ofIpv4(addr, resolver));
+        public int hashCode() {
+            return Objects.hash(ipAddresses);
         }
 
     }
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializer.java
index 0f171351fba..2d2ea05dc44 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializer.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializer.java
@@ -26,6 +26,7 @@ import com.yahoo.slime.Slime;
 import com.yahoo.slime.SlimeUtils;
 import com.yahoo.slime.Type;
 import com.yahoo.vespa.hosted.provision.Node;
+import com.yahoo.vespa.hosted.provision.node.Address;
 import com.yahoo.vespa.hosted.provision.node.Agent;
 import com.yahoo.vespa.hosted.provision.node.Allocation;
 import com.yahoo.vespa.hosted.provision.node.Generation;
@@ -43,6 +44,7 @@ import java.util.List;
 import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ExecutionException;
+import java.util.stream.Collectors;
 
 /**
  * Serializes a node to/from JSON.
@@ -66,6 +68,8 @@ public class NodeSerializer {
     private static final String hostnameKey = "hostname";
     private static final String ipAddressesKey = "ipAddresses";
     private static final String ipAddressPoolKey = "additionalIpAddresses";
+    private static final String containersKey = "containers";
+    private static final String containerHostnameKey = "hostname";
     private static final String idKey = "openStackId";
     private static final String parentHostnameKey = "parentHostname";
     private static final String historyKey = "history";
@@ -146,7 +150,8 @@ public class NodeSerializer {
     private void toSlime(Node node, Cursor object) {
         object.setString(hostnameKey, node.hostname());
         toSlime(node.ipConfig().primary(), object.setArray(ipAddressesKey));
-        toSlime(node.ipConfig().pool().asSet(), object.setArray(ipAddressPoolKey));
+        toSlime(node.ipConfig().pool().getIpSet(), object.setArray(ipAddressPoolKey));
+        toSlime(node.ipConfig().pool().getAddressList(), object);
         object.setString(idKey, node.id());
         node.parentHostname().ifPresent(hostname -> object.setString(parentHostnameKey, hostname));
         toSlime(node.flavor(), object);
@@ -214,6 +219,14 @@ public class NodeSerializer {
         ipAddresses.stream().map(IP::parse).sorted(IP.NATURAL_ORDER).map(IP::asString).forEach(array::addString);
     }
 
+    private void toSlime(List<Address> addresses, Cursor object) {
+        if (addresses.isEmpty()) return;
+        Cursor addressCursor = object.setArray(containersKey);
+        addresses.forEach(address -> {
+            addressCursor.addObject().setString(containerHostnameKey, address.hostname());
+        });
+    }
+
     // ---------------- Deserialization --------------------------------------------------
 
     public Node fromJson(Node.State state, byte[] data) {
@@ -232,7 +245,8 @@ public class NodeSerializer {
         Flavor flavor = flavorFromSlime(object);
         return new Node(object.field(idKey).asString(),
                         new IP.Config(ipAddressesFromSlime(object, ipAddressesKey),
-                                      ipAddressesFromSlime(object, ipAddressPoolKey)),
+                                      ipAddressesFromSlime(object, ipAddressPoolKey),
+                                      addressesFromSlime(object)),
                         object.field(hostnameKey).asString(),
                         parentHostnameFromSlime(object),
                         flavor,
@@ -358,6 +372,12 @@ public class NodeSerializer {
         return ipAddresses.build();
     }
 
+    private List<Address> addressesFromSlime(Inspector object) {
+        return SlimeUtils.entriesStream(object.field(containersKey))
+                .map(elem -> new Address(elem.field(containerHostnameKey).asString()))
+                .collect(Collectors.toList());
+    }
+
     private Optional<String> modelNameFromSlime(Inspector object) {
         if (object.field(modelNameKey).valid()) {
             return Optional.of(object.field(modelNameKey).asString());
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodePatcher.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodePatcher.java
index f2755176124..832310cf2c9 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodePatcher.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodePatcher.java
@@ -15,6 +15,7 @@ import com.yahoo.slime.SlimeUtils;
 import com.yahoo.slime.Type;
 import com.yahoo.vespa.hosted.provision.LockedNodeList;
 import com.yahoo.vespa.hosted.provision.Node;
+import com.yahoo.vespa.hosted.provision.node.Address;
 import com.yahoo.vespa.hosted.provision.node.Agent;
 import com.yahoo.vespa.hosted.provision.node.Allocation;
 import com.yahoo.vespa.hosted.provision.node.IP;
@@ -26,6 +27,7 @@ import java.io.InputStream;
 import java.io.UncheckedIOException;
 import java.time.Clock;
 import java.time.Instant;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -116,9 +118,11 @@ public class NodePatcher {
             case "parentHostname" :
                 return node.withParentHostname(asString(value));
             case "ipAddresses" :
-                return IP.Config.verify(node.with(node.ipConfig().with(asStringSet(value))), memoizedNodes.get());
+                return IP.Config.verify(node.with(node.ipConfig().withPrimary(asStringSet(value))), memoizedNodes.get());
             case "additionalIpAddresses" :
-                return IP.Config.verify(node.with(node.ipConfig().with(IP.Pool.of(asStringSet(value)))), memoizedNodes.get());
+                return IP.Config.verify(node.with(node.ipConfig().withPool(node.ipConfig().pool().withIpAddresses(asStringSet(value)))), memoizedNodes.get());
+            case "additionalHostnames" :
+                return IP.Config.verify(node.with(node.ipConfig().withPool(node.ipConfig().pool().withAddresses(asAddressList(value)))), memoizedNodes.get());
             case WANT_TO_RETIRE :
             case WANT_TO_DEPROVISION :
                 boolean wantToRetire = asOptionalBoolean(root.field(WANT_TO_RETIRE)).orElse(node.status().wantToRetire());
@@ -212,6 +216,22 @@ public class NodePatcher {
         return strings;
     }
 
+    private List<Address> asAddressList(Inspector field) {
+        if ( ! field.type().equals(Type.ARRAY))
+            throw new IllegalArgumentException("Expected an ARRAY value, got a " + field.type());
+
+        List<Address> addresses = new ArrayList<>(field.entries());
+        for (int i = 0; i < field.entries(); i++) {
+            Inspector entry = field.entry(i);
+            if ( ! entry.type().equals(Type.STRING))
+                throw new IllegalArgumentException("Expected a STRING value, got a " + entry.type());
+            Address address = new Address(entry.asString());
+            addresses.add(address);
+        }
+
+        return addresses;
+    }
+
     private Node patchRequiredDiskSpeed(Node node, String value) {
         Optional<Allocation> allocation = node.allocation();
         if (allocation.isPresent())
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodesResponse.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodesResponse.java
index 39375494d01..3a9246379cf 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodesResponse.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodesResponse.java
@@ -15,6 +15,7 @@ import com.yahoo.slime.Slime;
 import com.yahoo.vespa.applicationmodel.HostName;
 import com.yahoo.vespa.hosted.provision.Node;
 import com.yahoo.vespa.hosted.provision.NodeRepository;
+import com.yahoo.vespa.hosted.provision.node.Address;
 import com.yahoo.vespa.hosted.provision.node.History;
 import com.yahoo.vespa.hosted.provision.node.filter.NodeFilter;
 import com.yahoo.vespa.orchestrator.Orchestrator;
@@ -186,7 +187,8 @@ class NodesResponse extends HttpResponse {
         object.setBool("wantToDeprovision", node.status().wantToDeprovision());
         toSlime(node.history(), object.setArray("history"));
         ipAddressesToSlime(node.ipConfig().primary(), object.setArray("ipAddresses"));
-        ipAddressesToSlime(node.ipConfig().pool().asSet(), object.setArray("additionalIpAddresses"));
+        ipAddressesToSlime(node.ipConfig().pool().getIpSet(), object.setArray("additionalIpAddresses"));
+        addressesToSlime(node.ipConfig().pool().getAddressList(), object);
         node.reports().toSlime(object, "reports");
         node.modelName().ifPresent(modelName -> object.setString("modelName", modelName));
         node.switchHostname().ifPresent(switchHostname -> object.setString("switchHostname", switchHostname));
@@ -229,6 +231,13 @@ class NodesResponse extends HttpResponse {
         ipAddresses.forEach(array::addString);
     }
 
+    private void addressesToSlime(List<Address> addresses, Cursor object) {
+        if (addresses.isEmpty()) return;
+        // When/if Address becomes richer: add another field (e.g. "addresses") and expand to array of objects
+        Cursor addressesArray = object.setArray("additionalHostnames");
+        addresses.forEach(address -> addressesArray.addString(address.hostname()));
+    }
+
     private String lastElement(String path) {
         if (path.endsWith("/"))
             path = path.substring(0, path.length()-1);
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodesV2ApiHandler.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodesV2ApiHandler.java
index 59604d094fa..304cebb3c01 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodesV2ApiHandler.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/restapi/NodesV2ApiHandler.java
@@ -257,7 +257,7 @@ public class NodesV2ApiHandler extends LoggingRequestHandler {
         inspector.field("additionalIpAddresses").traverse((ArrayTraverser) (i, item) -> ipAddressPool.add(item.asString()));
 
         Node.Builder builder = Node.create(inspector.field("openStackId").asString(),
-                                           new IP.Config(ipAddresses, ipAddressPool),
+                                           IP.Config.of(ipAddresses, ipAddressPool, List.of()),
                                            inspector.field("hostname").asString(),
                                            flavorFromSlime(inspector),
                                            nodeTypeFromSlime(inspector.field("type")));
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockNodeRepository.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockNodeRepository.java
index fb78e76f0c7..b24d2417db5 100644
--- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockNodeRepository.java
+++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/testutils/MockNodeRepository.java
@@ -206,11 +206,11 @@ public class MockNodeRepository extends NodeRepository {
 
     private IP.Config ipConfig(int nodeIndex, int primarySize, int poolSize) {
         var primary = new LinkedHashSet<String>();
-        var pool = new LinkedHashSet<String>();
+        var ipPool = new LinkedHashSet<String>();
         for (int i = 1; i <= primarySize + poolSize; i++) {
             var set = primary;
             if (i > primarySize) {
-                set = pool;
+                set = ipPool;
             }
             var rootName = "test-node-primary";
             if (i > primarySize) {
@@ -226,7 +226,7 @@ public class MockNodeRepository extends NodeRepository {
                 set.add(ipv4Address);
             }
         }
-        return new IP.Config(primary, pool);
+        return IP.Config.of(primary, ipPool, List.of());
     }
 
     private IP.Config ipConfig(int nodeIndex) {
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/DynamicProvisioningMaintainerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/DynamicProvisioningMaintainerTest.java
index c08e51bf0cc..478376bc0cd 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/DynamicProvisioningMaintainerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/maintenance/DynamicProvisioningMaintainerTest.java
@@ -66,9 +66,9 @@ public class DynamicProvisioningMaintainerTest {
         assertTrue("No IP addresses assigned",
                    Stream.of(host3, host4, host41).map(node -> node.ipConfig().primary()).allMatch(Set::isEmpty));
 
-        Node host3new = host3.with(host3.ipConfig().with(Set.of("::3:0")));
-        Node host4new = host4.with(host4.ipConfig().with(Set.of("::4:0")));
-        Node host41new = host41.with(host41.ipConfig().with(Set.of("::4:1", "::4:2")));
+        Node host3new = host3.with(host3.ipConfig().withPrimary(Set.of("::3:0")));
+        Node host4new = host4.with(host4.ipConfig().withPrimary(Set.of("::4:0")));
+        Node host41new = host41.with(host41.ipConfig().withPrimary(Set.of("::4:1", "::4:2")));
 
         tester.maintainer.maintain();
         assertEquals(host3new, tester.nodeRepository.getNode("host3").get());
@@ -290,7 +290,7 @@ public class DynamicProvisioningMaintainerTest {
                             Generation.initial(),
                             false));
             Node.Builder builder = Node.create("fake-id-" + hostname, hostname, flavor, state, nodeType)
-                    .ipConfig(state == Node.State.active ? Set.of("::1") : Set.of(), Set.of());
+                    .ipConfigWithEmptyPool(state == Node.State.active ? Set.of("::1") : Set.of());
             parentHostname.ifPresent(builder::parentHostname);
             allocation.ifPresent(builder::allocation);
             return builder.build();
@@ -382,16 +382,18 @@ public class DynamicProvisioningMaintainerTest {
             if (node.parentHostname().isPresent()) return node;
             int hostIndex = Integer.parseInt(node.hostname().replaceAll("^[a-z]+|-\\d+$", ""));
             Set<String> addresses = Set.of("::" + hostIndex + ":0");
-            Set<String> pool = new HashSet<>();
+            Set<String> ipAddressPool = new HashSet<>();
             if (!behaviours.contains(Behaviour.failDnsUpdate)) {
                 nameResolver.addRecord(node.hostname(), addresses.iterator().next());
                 for (int i = 1; i <= 2; i++) {
                     String ip = "::" + hostIndex + ":" + i;
-                    pool.add(ip);
+                    ipAddressPool.add(ip);
                     nameResolver.addRecord(node.hostname() + "-" + i, ip);
                 }
             }
-            return node.with(node.ipConfig().with(addresses).with(IP.Pool.of(pool)));
+
+            IP.Pool pool = node.ipConfig().pool().withIpAddresses(ipAddressPool);
+            return node.with(node.ipConfig().withPrimary(addresses).withPool(pool));
         }
 
         enum Behaviour {
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/node/IPTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/node/IPTest.java
index a209ea206d3..fb9c1ad0e5a 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/node/IPTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/node/IPTest.java
@@ -177,7 +177,7 @@ public class IPTest {
         }
 
         IP.Pool pool = node.ipConfig().pool();
-        assertNotEquals(dualStack, pool instanceof IP.Ipv4Pool);
+        assertNotEquals(dualStack, pool.getProtocol() == IP.IpAddresses.Protocol.ipv4);
         return pool;
     }
 
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializerTest.java
index 10e3592e548..8b9d60aeaf4 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializerTest.java
@@ -21,6 +21,7 @@ import com.yahoo.test.ManualClock;
 import com.yahoo.text.Utf8;
 import com.yahoo.vespa.hosted.provision.Node;
 import com.yahoo.vespa.hosted.provision.Node.State;
+import com.yahoo.vespa.hosted.provision.node.Address;
 import com.yahoo.vespa.hosted.provision.node.Agent;
 import com.yahoo.vespa.hosted.provision.node.Generation;
 import com.yahoo.vespa.hosted.provision.node.History;
@@ -249,15 +250,19 @@ public class NodeSerializerTest {
     public void serialize_ip_address_pool() {
         Node node = createNode();
 
-        // Test round-trip with IP address pool
-        node = node.with(node.ipConfig().with(IP.Pool.of(Set.of("::1", "::2", "::3"))));
+        // Test round-trip with address pool
+        node = node.with(node.ipConfig().withPool(IP.Pool.of(
+                Set.of("::1", "::2", "::3"),
+                List.of(new Address("a"), new Address("b"), new Address("c")))));
         Node copy = nodeSerializer.fromJson(node.state(), nodeSerializer.toJson(node));
-        assertEquals(node.ipConfig().pool().asSet(), copy.ipConfig().pool().asSet());
+        assertEquals(node.ipConfig().pool().getIpSet(), copy.ipConfig().pool().getIpSet());
+        assertEquals(Set.copyOf(node.ipConfig().pool().getAddressList()), Set.copyOf(copy.ipConfig().pool().getAddressList()));
 
-        // Test round-trip without IP address pool (handle empty pool)
+        // Test round-trip without address pool (handle empty pool)
         node = createNode();
         copy = nodeSerializer.fromJson(node.state(), nodeSerializer.toJson(node));
-        assertEquals(node.ipConfig().pool().asSet(), copy.ipConfig().pool().asSet());
+        assertEquals(node.ipConfig().pool().getIpSet(), copy.ipConfig().pool().getIpSet());
+        assertEquals(Set.copyOf(node.ipConfig().pool().getAddressList()), Set.copyOf(copy.ipConfig().pool().getAddressList()));
     }
 
     @Test
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/AllocationSimulator.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/AllocationSimulator.java
index b76588b7036..24b3139a91b 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/AllocationSimulator.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/AllocationSimulator.java
@@ -11,6 +11,7 @@ import com.yahoo.vespa.hosted.provision.Node;
 import com.yahoo.vespa.hosted.provision.NodeList;
 import com.yahoo.vespa.hosted.provision.node.Allocation;
 import com.yahoo.vespa.hosted.provision.node.Generation;
+import com.yahoo.vespa.hosted.provision.node.IP;
 
 import javax.swing.JFrame;
 import java.util.ArrayList;
@@ -76,7 +77,7 @@ public class AllocationSimulator {
         Node.Builder builder = Node.create("fake", hostname, flavor,
                 parent.isPresent() ? Node.State.ready : Node.State.active,
                 parent.isPresent() ? NodeType.tenant : NodeType.host)
-                .ipConfig(Set.of("127.0.0.1"), parent.isPresent() ? Set.of() : getAdditionalIP());
+                .ipConfig(IP.Config.of(Set.of("127.0.0.1"), parent.isPresent() ? Set.of() : getAdditionalIP(), List.of()));
         parent.ifPresent(builder::parentHostname);
         allocation(tenant, flavor).ifPresent(builder::allocation);
 
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/HostCapacityTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/HostCapacityTest.java
index 4891387e9e8..c6e89680e85 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/HostCapacityTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/HostCapacityTest.java
@@ -43,9 +43,9 @@ public class HostCapacityTest {
         NodeFlavors nodeFlavors = FlavorConfigBuilder.createDummies("host", "docker", "docker2");
 
         // Create three docker hosts
-        host1 = Node.create("host1", new IP.Config(Set.of("::1"), generateIPs(2, 4)), "host1", nodeFlavors.getFlavorOrThrow("host"), NodeType.host).build();
-        host2 = Node.create("host2", new IP.Config(Set.of("::11"), generateIPs(12, 3)), "host2", nodeFlavors.getFlavorOrThrow("host"), NodeType.host).build();
-        host3 = Node.create("host3", new IP.Config(Set.of("::21"), generateIPs(22, 1)), "host3", nodeFlavors.getFlavorOrThrow("host"), NodeType.host).build();
+        host1 = Node.create("host1", IP.Config.of(Set.of("::1"), generateIPs(2, 4), List.of()), "host1", nodeFlavors.getFlavorOrThrow("host"), NodeType.host).build();
+        host2 = Node.create("host2", IP.Config.of(Set.of("::11"), generateIPs(12, 3), List.of()), "host2", nodeFlavors.getFlavorOrThrow("host"), NodeType.host).build();
+        host3 = Node.create("host3", IP.Config.of(Set.of("::21"), generateIPs(22, 1), List.of()), "host3", nodeFlavors.getFlavorOrThrow("host"), NodeType.host).build();
 
         // Add two containers to host1
         var nodeA = Node.createDockerNode(Set.of("::2"), "nodeA", "host1", resources1, NodeType.tenant).build();
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/LoadBalancerProvisionerTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/LoadBalancerProvisionerTest.java
index fe1fb43dcb9..c51ef7250e2 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/LoadBalancerProvisionerTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/LoadBalancerProvisionerTest.java
@@ -256,7 +256,7 @@ public class LoadBalancerProvisionerTest {
     private void assignIps(List<Node> nodes) {
         try (var lock = tester.nodeRepository().lockUnallocated()) {
             for (int i = 0; i < nodes.size(); i++) {
-                tester.nodeRepository().write(nodes.get(i).with(IP.Config.EMPTY.with(Set.of("127.0.0." + i))), lock);
+                tester.nodeRepository().write(nodes.get(i).with(IP.Config.EMPTY.withPrimary(Set.of("127.0.0." + i))), lock);
             }
         }
     }
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/NodeCandidateTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/NodeCandidateTest.java
index 7f637ba8804..8aa362aa932 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/NodeCandidateTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/NodeCandidateTest.java
@@ -133,7 +133,7 @@ public class NodeCandidateTest {
 
     private static Node node(String hostname, Node.State state) {
         return Node.create(hostname, hostname, new Flavor(new NodeResources(2, 2, 2, 2)), state, NodeType.tenant)
-                .ipConfig(Set.of("::1"), Set.of()).build();
+                .ipConfigWithEmptyPool(Set.of("::1")).build();
     }
 
     private static NodeCandidate node(String hostname,
@@ -143,9 +143,9 @@ public class NodeCandidateTest {
                                       boolean exclusiveSwitch) {
         Node node = Node.create(hostname, hostname, new Flavor(nodeResources), Node.State.ready, NodeType.tenant)
                 .parentHostname(hostname + "parent")
-                .ipConfig(Set.of("::1"), Set.of()).build();
+                .ipConfigWithEmptyPool(Set.of("::1")).build();
         Node parent = Node.create(hostname + "parent", hostname, new Flavor(totalHostResources), Node.State.ready, NodeType.host)
-                .ipConfig(Set.of("::1"), Set.of()).build();
+                .ipConfigWithEmptyPool(Set.of("::1")).build();
         return new NodeCandidate.ConcreteNodeCandidate(node, totalHostResources.subtract(allocatedHostResources), Optional.of(parent),
                                                        false, exclusiveSwitch, false, true, false);
     }
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/ProvisioningTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/ProvisioningTest.java
index 82b20bcae14..2fe39780cf5 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/ProvisioningTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/ProvisioningTest.java
@@ -894,7 +894,7 @@ public class ProvisioningTest {
         Flavor flavor = tester.nodeRepository().flavors().getFlavorOrThrow("default");
         List<Node> nodes = List.of(
                 Node.create("cfghost1", new IP.Config(Set.of("::1:0"), Set.of("::1:1")), "cfghost1", flavor, NodeType.confighost).build(),
-                Node.create("cfghost2", new IP.Config(Set.of("::2:0"), Set.of("::2:1")), "cfghost2", flavor, NodeType.confighost).ipConfig(Set.of("::2:0"), Set.of("::2:1")).build(),
+                Node.create("cfghost2", new IP.Config(Set.of("::2:0"), Set.of("::2:1")), "cfghost2", flavor, NodeType.confighost).ipConfig(IP.Config.of(Set.of("::2:0"), Set.of("::2:1"), List.of())).build(),
                 Node.create("cfg1", new IP.Config(Set.of("::1:1"), Set.of()), "cfg1", flavor, NodeType.config).parentHostname("cfghost1").build(),
                 Node.create("cfg2", new IP.Config(Set.of("::2:1"), Set.of()), "cfg2", flavor, NodeType.config).parentHostname("cfghost2").build());
         tester.nodeRepository().setReady(tester.nodeRepository().addNodes(nodes, Agent.system), Agent.system, ProvisioningTest.class.getSimpleName());
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/NodesV2ApiTest.java b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/NodesV2ApiTest.java
index 97f850102fc..a98d383e219 100644
--- a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/NodesV2ApiTest.java
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/NodesV2ApiTest.java
@@ -360,6 +360,23 @@ public class NodesV2ApiTest {
     }
 
     @Test
+    public void patch_hostnames() throws IOException {
+        assertFile(new Request("http://localhost:8080/nodes/v2/node/host4.yahoo.com"), "node4.json");
+
+        assertResponse(new Request("http://localhost:8080/nodes/v2/node/host4.yahoo.com",
+                        Utf8.toBytes("{\"additionalHostnames\": [\"a\",\"b\"]}"), Request.Method.PATCH),
+                "{\"message\":\"Updated host4.yahoo.com\"}");
+
+        assertFile(new Request("http://localhost:8080/nodes/v2/node/host4.yahoo.com"), "node4-with-hostnames.json");
+
+        assertResponse(new Request("http://localhost:8080/nodes/v2/node/host4.yahoo.com",
+                        Utf8.toBytes("{\"additionalHostnames\": []}"), Request.Method.PATCH),
+                "{\"message\":\"Updated host4.yahoo.com\"}");
+
+        assertFile(new Request("http://localhost:8080/nodes/v2/node/host4.yahoo.com"), "node4.json");
+    }
+
+    @Test
     public void post_controller_node() throws Exception {
         String data = "[{\"hostname\":\"controller1.yahoo.com\", \"openStackId\":\"fake-controller1.yahoo.com\"," +
                       createIpAddresses("127.0.0.1") +
diff --git a/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/responses/node4-with-hostnames.json b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/responses/node4-with-hostnames.json
new file mode 100644
index 00000000000..40b5f29c13f
--- /dev/null
+++ b/node-repository/src/test/java/com/yahoo/vespa/hosted/provision/restapi/responses/node4-with-hostnames.json
@@ -0,0 +1,65 @@
+{
+  "url": "http://localhost:8080/nodes/v2/node/host4.yahoo.com",
+  "id": "host4.yahoo.com",
+  "state": "active",
+  "type": "tenant",
+  "hostname": "host4.yahoo.com",
+  "parentHostname": "dockerhost1.yahoo.com",
+  "openStackId": "node4",
+  "flavor": "[vcpu: 1.0, memory: 4.0 Gb, disk 100.0 Gb, bandwidth: 1.0 Gbps, storage type: local]",
+  "resources":{"vcpu":1.0,"memoryGb":4.0,"diskGb":100.0,"bandwidthGbps":1.0,"diskSpeed":"fast","storageType":"local"},
+  "environment": "DOCKER_CONTAINER",
+  "owner": {
+    "tenant": "tenant3",
+    "application": "application3",
+    "instance": "instance3"
+  },
+  "membership": {
+    "clustertype": "content",
+    "clusterid": "id3",
+    "group": "0",
+    "index": 0,
+    "retired": false
+  },
+  "restartGeneration": 0,
+  "currentRestartGeneration": 0,
+  "wantedDockerImage": "docker-registry.domain.tld:8080/dist/vespa:6.42.0",
+  "wantedVespaVersion": "6.42.0",
+  "requestedResources": { "vcpu":1.0, "memoryGb":4.0, "diskGb":100.0, "bandwidthGbps":1.0, "diskSpeed":"fast", "storageType":"any" },
+  "allowedToBeDown": false,
+  "rebootGeneration": 1,
+  "currentRebootGeneration": 0,
+  "vespaVersion": "6.41.0",
+  "currentDockerImage": "docker-registry.domain.tld:8080/dist/vespa:6.41.0",
+  "failCount": 0,
+  "wantToRetire": false,
+  "wantToDeprovision": false,
+  "history": [
+    {
+      "event": "provisioned",
+      "at": 123,
+      "agent": "system"
+    },
+    {
+      "event": "readied",
+      "at": 123,
+      "agent": "system"
+    },
+    {
+      "event": "reserved",
+      "at": 123,
+      "agent": "application"
+    },
+    {
+      "event": "activated",
+      "at": 123,
+      "agent": "application"
+    }
+  ],
+  "ipAddresses": [
+    "127.0.4.1",
+    "::4:1"
+  ],
+  "additionalIpAddresses": [],
+  "additionalHostnames": ["a","b"]
+}