Wrong "index.routing.allocation.enable" value prevents all allocation

[masaruh]

(This happens on 1.7.3 and 2.1.0)

On single node cluster, do this

PUT recoverytest

PUT recoverytest/_settings
{
  "index.routing.allocation.enable": "true"
}

and restart node.
You get this exception and no shard is allocated.

[2016-01-12 17:04:52,871][ERROR][cluster.routing          ] [Blue Shield] unexpected failure during [cluster_reroute(async_shard_fetch)], current state version [2]
java.lang.IllegalArgumentException: Illegal allocation.enable value [TRUE]
    at org.elasticsearch.cluster.routing.allocation.decider.EnableAllocationDecider$Allocation.parse(EnableAllocationDecider.java:189)
    at org.elasticsearch.cluster.routing.allocation.decider.EnableAllocationDecider.canAllocate(EnableAllocationDecider.java:91)
    at org.elasticsearch.cluster.routing.allocation.decider.AllocationDeciders.canAllocate(AllocationDeciders.java:74)
    at org.elasticsearch.gateway.PrimaryShardAllocator.buildNodesToAllocate(PrimaryShardAllocator.java:179)
    at org.elasticsearch.gateway.PrimaryShardAllocator.allocateUnassigned(PrimaryShardAllocator.java:96)
    at org.elasticsearch.gateway.GatewayAllocator.allocateUnassigned(GatewayAllocator.java:125)
    at org.elasticsearch.cluster.routing.allocation.allocator.ShardsAllocators.allocateUnassigned(ShardsAllocators.java:72)
    at org.elasticsearch.cluster.routing.allocation.AllocationService.reroute(AllocationService.java:175)
    at org.elasticsearch.cluster.routing.allocation.AllocationService.reroute(AllocationService.java:155)
    at org.elasticsearch.cluster.routing.allocation.AllocationService.reroute(AllocationService.java:141)
    at org.elasticsearch.cluster.routing.RoutingService$2.execute(RoutingService.java:176)
    at org.elasticsearch.cluster.service.InternalClusterService$UpdateTask.run(InternalClusterService.java:388)
    at org.elasticsearch.common.util.concurrent.PrioritizedEsThreadPoolExecutor$TieBreakingPrioritizedRunnable.runAndClean(PrioritizedEsThreadPoolExecutor.java:231)
    at org.elasticsearch.common.util.concurrent.PrioritizedEsThreadPoolExecutor$TieBreakingPrioritizedRunnable.run(PrioritizedEsThreadPoolExecutor.java:194)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

I think one wrong value in index level setting shouldn't prevent other indices' shards allocation.
Could be dup of #6732 since this shouldn't happen if you can't set wrong value.

[clintongormley]

Fixed by #15278

[haiguo]

What we saw is that entire cluster recover can be stopped by a bad setting on a single index. Master node will stop directly recovery when an IllegalArgumentException is thrown. Is that fixed in 15278?

[clintongormley]

I missed the fact that this is an index setting rather than a cluster setting. Index settings are still being worked on, but yes, the validation of index settings will fix this. This will be fixed once #6732 is closed

[promiseofcake]

What can we do if we are currently in this state short of upgrading? (2.4.2)