public List<Node> restartActive(Predicate<Node> filter) {
        return performOn(NodeFilter.in(Set.of(State.active)).and(filter),
                         (node, lock) -> write(node.withRestart(node.allocation().get().restartGeneration().withIncreasedWanted()),
                                               lock));
    }
Increases the restart generation of the active nodes matching given filter.

@return the nodes in their new state
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/node/Nodes.java