public Node withWantedOsVersion(Optional<Version> version) {
        if (status.osVersion().wanted().equals(version)) return this;
        return with(status.withOsVersion(status.osVersion().withWanted(version)));
    }
Returns a copy of this node with wanted OS version set to given version
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/Node.java