Shell执行过程中被阻塞住，进程被挂起

[牵着蜗牛去散步_]

问题现象:
在执行脚本的时候，会概率性的出现，脚本执行到一半卡主的情况



查看进程，发现这条命令sleep了



求大神告知下什么原因。

shell脚本逻辑：

#!/bin/bash
set -x
namespace=onap
recovery_tmp=/opt/matrix/app/data/recovery_tmp

#替换文件
replaceFile(){
   j=0
   cassandra_pod=`kubectl get pods -n ${namespace} | grep dev-sdc-cs| grep -v sdc-cs-c | awk -F ' ' '{print $1}'`
   for i in ${cassandra_pod}; do
        kubectl exec ${i} -n ${namespace}  -- rm -rf /var/lib/sdc_cs/ 
                dlog "------------rm -rf ${i} /var/lib/sdc_cs/ end------------- "
                sleep 3
                kubectl cp ${recovery_tmp}/sdc_cs/cassandra-${j}/commitlog ${namespace}/${i}:/var/lib/cassandra         >/dev/null
                kubectl cp ${recovery_tmp}/sdc_cs/cassandra-${j}/data ${namespace}/${i}:/var/lib/cassandra      >/dev/null
               kubectl cp ${recovery_tmp}/sdc_cs/cassandra-${j}/saved_caches/ ${namespace}/${i}:/var/lib/cassandra >/dev/null
                if [ "${?}" -ne 0 ]; then
                        dlog "[ERROR][${i}] cassandra replace failed."
                        info 1 "[${i}] cassandra replace"
                        exit -1;
                else
                        dlog "[INFO][${i}] cassandra replace finished."
                fi
                let j+=1
  done
           return 0
}

replaceFile