Elasticsearch enabling slow logs to all the indices in cluster at once?

[Yaswanth]

ES 2.4.0

I know that we can enable slow log per-index level but i want to enabling for all the indices in my cluster at once.
So i tried giving the setting for the whole cluster:

PUT _cluster/settings
     {
      "transient": {
        "index.search.slowlog.threshold.query.trace": "0s",
        "index.search.slowlog.threshold.fetch.trace": "0s",
        "index.indexing.slowlog.threshold.index.trace": "0s"
      }
    }

It thrown the error like this:
[2017-02-22 12:44:33,650][WARN ][action.admin.cluster.settings] [Powderkeg] igno ring transient setting [index.indexing.slowlog.threshold.index.trace], not dynam ically updateable [2017-02-22 12:44:33,651][WARN ][action.admin.cluster.settings] [Powderkeg] igno ring transient setting [index.search.slowlog.threshold.fetch.trace], not dynamic ally updateable [2017-02-22 12:44:33,651][WARN ][action.admin.cluster.settings] [Powderkeg] igno ring transient setting [index.search.slowlog.threshold.query.trace], not dynamic ally updateable [2017-02-22 13:58:30,051][WARN ][action.admin.cluster.settings] [Powderkeg] igno ring transient setting [index.indexing.slowlog.threshold.index.debug], not dynam ically updateable [2017-02-22 13:58:30,051][WARN ][action.admin.cluster.settings] [Powderkeg] igno ring transient setting [index.search.slowlog.threshold.fetch.debug], not dynamic ally updateable [2017-02-22 13:58:30,052][WARN ][action.admin.cluster.settings] [Powderkeg] igno ring transient setting [index.search.slowlog.threshold.query.debug], not dynamic ally updateable

[Yaswanth]

This can't be done at cluster level this can only be done at per-index level.

PUT indexname/settings
     {
        "index.search.slowlog.threshold.query.trace": "0s",
        "index.search.slowlog.threshold.fetch.trace": "0s",
        "index.indexing.slowlog.threshold.index.trace": "0s"
    }