public AllocatedHosts toAllocatedHosts() {
        // Preserve add order for tests
        Set<HostSpec> hostSet = new LinkedHashSet<>();
        for (var host : hosts.values())
            hostSet.add(host.getFirst());
        return AllocatedHosts.withHosts(hostSet);
    }
Adds the nodes allocated for a particular model version.
configserver/src/main/java/com/yahoo/vespa/config/server/modelfactory/AllocatedHostsFromAllModels.java