我在服务器上通过SSH启动了logstash，但是连接到Elasticsearch时出现错误。当我尝试按CTRL+C时，Logstash没有停止，并且现在仍在运行。我如何强制它停止？
我的服务器运行CentOS5

Got error to send bulk of actions to elasticsearch server at localhost : blocked by: [SERVICE_UNAVAILABLE/1/state not recovered / initialized];[SERVICE_UNAVAILABLE/2/no master]; {:level=>:error}
Failed to flush outgoing items {:outgoing_count=>552, :exception=>org.elasticsearch.cluster.block.ClusterBlockException: blocked by: [SERVICE_UNAVAILABLE/1/state not recovered / initialized];[SERVICE_UNAVAILABLE/2/no master];, :backtrace=>["org.elasticsearch.cluster.block.ClusterBlocks.globalBlockedException(org/elasticsearch/cluster/block/ClusterBlocks.java:151)", "org.elasticsearch.cluster.block.ClusterBlocks.globalBlockedRaiseException(org/elasticsearch/cluster/block/ClusterBlocks.java:141)", "org.elasticsearch.action.bulk.TransportBulkAction.executeBulk(org/elasticsearch/action/bulk/TransportBulkAction.java:210)", "org.elasticsearch.action.bulk.TransportBulkAction.access$000(org/elasticsearch/action/bulk/TransportBulkAction.java:73)", "org.elasticsearch.action.bulk.TransportBulkAction$1.onFailure(org/elasticsearch/action/bulk/TransportBulkAction.java:148)", "org.elasticsearch.action.support.TransportAction$ThreadedActionListener$2.run(org/elasticsearch/action/support/TransportAction.java:137)", "java.util.concurrent.ThreadPoolExecutor.runWorker(java/util/concurrent/ThreadPoolExecutor.java:1145)", "java.util.concurrent.ThreadPoolExecutor$Worker.run(java/util/concurrent/ThreadPoolExecutor.java:615)", "java.lang.Thread.run(java/lang/Thread.java:745)"], :level=>:warn}
SIGTERM received. Shutting down the pipeline. {:level=>:warn}
^CSIGINT received. Shutting down the pipeline. {:level=>:warn}
^CSIGINT received. Shutting down the pipeline. {:level=>:warn}
^CSIGINT received. Shutting down the pipeline. {:level=>:warn}
^CSIGINT received. Shutting down the pipeline. {:level=>:warn}