# 账号锁定导致启动Kafka组件失败
#### 问题背景与现象
新创建的MRS集群，启动Kafka服务失败。
查看服务启动日志，显示认证失败。
```
/home/omm/kerberos/bin/kinit -k -t ${BIGDATA_HOME}/etc/2_15_ Broker /kafka.keytab kafka/hadoop.hadoop.com -c ${BIGDATA_HOME}/etc/2_15_ Broker /11846 failed.
export key tab file for kafka/hadoop.hadoop.com failed.export and check keytab file failed, errMsg=]}] for Broker #192.168.1.92@192-168-1-92.
[2015-07-11 02:34:33] RoleInstance started failure for ROLE[name: Broker].
[2015-07-11 02:34:34] Failed to complete the instances start operation. Current operation entities: [Broker #192.168.1.92@192-168-1-92], Failure entities : [Broker #192.168.1.92@192-168-1-92].Operation Failed. Failed to complete the instances start operation. Current operation entities: [Broker#192.168.1.92@192-168-1-92], Failure entities: [Broker #192.168.1.92@192-168-1-92].
```
#### 原因分析
查看Kerberos日志"/var/log/Bigdata/kerberos/krb5kdc.log"，发现有集群外的IP使用Kafka用户连接，导致多次认证失败，最终导致Kafka账号被锁定。
```
Jul 11 02:49:16 192-168-1-91 krb5kdc[1863](info): AS_REQ (2 etypes {18 17}) 192.168.1.93: NEEDED_PREAUTH: kafka/hadoop.hadoop.com@HADOOP.COM for krbtgt/HADOOP.COM@HADOOP.COM, Additional pre-authentication required
Jul 11 02:49:16 192-168-1-91 krb5kdc[1863](info): preauth (encrypted_timestamp) verify failure: Decrypt integrity check failed
Jul 11 02:49:16 192-168-1-91 krb5kdc[1863](info): AS_REQ (2 etypes {18 17}) 192.168.1.93: PREAUTH_FAILED: kafka/hadoop.hadoop.com@HADOOP.COM for krbtgt/HADOOP.COM@HADOOP.COM, Decrypt integrity check failed
```
#### 解决办法
1. 确认集群外连接Kafka的节点IP地址信息（如原因分析示例中的192.168.1.93）。
2. 登录集群外的节点，断开其对Kafka的认证。
3. 等待5分钟，此账号就会被解锁。
4. 重新尝试启动Kafka服务。