如何运行带外部数据目录的Percona XtraDB集群？

当我运行带有外部数据目录的Percona XtraDB集群 （我尝试从用Percona XtraBackup制作的备份中恢复）时，出现错误：

--initialize specified but the data directory has files in it. Aborting. 

我该如何解决？

Docker命令：

 docker run --name xtradb_from_backup -p 3307:3306 \ -e MYSQL_ROOT_PASSWORD=1 -e XTRABACKUP_PASSWORD=2 \ -e CLUSTER_NAME=xtradb -d -v ~/mysql/:/etc/mysql/conf.d \ -v /db:/var/lib/mysql percona/percona-xtradb-cluster:5.7.16 \ --pxc_strict_mode=PERMISSIVE; 

另外我也试过根据文档省略MYSQL_ROOT_PASSWORD ：

 docker run --name xtradb_from_backup -p 3307:3306 \ -e MYSQL_ALLOW_EMPTY_PASSWORD=yes -e XTRABACKUP_PASSWORD=2 \ -e CLUSTER_NAME=xtradb -d -v ~/mysql/:/etc/mysql/conf.d \ -v /db:/var/lib/mysql percona/percona-xtradb-cluster:5.7.16 \ --pxc_strict_mode=PERMISSIVE; 

错误日志：

 Running --initialize-insecure on /var/lib/mysql/ total 345M drwxrwxr-x 7 1001 root 4.0K Apr 13 14:53 . drwxr-xr-x 19 root root 4.0K Dec 15 21:40 .. -rw-r----- 1 1001 root 56 Apr 13 09:28 auto.cnf ... -rw-r----- 1 1001 root 3.8M Apr 13 14:27 xb_doublewrite -rw-r--r-- 1 1001 root 23 Apr 13 09:14 xtrabackup_binlog_info -rw-r--r-- 1 1001 root 23 Apr 13 10:23 xtrabackup_binlog_pos_innodb -rw-rw---- 1 1001 root 123 Apr 13 10:23 xtrabackup_checkpoints -rw-r--r-- 1 1001 root 46 Apr 13 09:14 xtrabackup_galera_info -rw-rw---- 1 1001 root 549 Apr 11 00:34 xtrabackup_info -rw-rw---- 1 1001 root 158M Apr 13 09:14 xtrabackup_logfile 2017-04-13T14:53:02.875351Z 0 [Warning] 'NO_ZERO_DATE', 'NO_ZERO_IN_DATE' and 'ERROR_FOR_DIVISION_BY_ZERO' sql modes should be used with strict mode. They will be merged with strict mode in a future release. 2017-04-13T14:53:02.875413Z 0 [Warning] 'NO_AUTO_CREATE_USER' sql mode was not set. 2017-04-13T14:53:02.875473Z 0 [Warning] WSREP: Node is running in bootstrap/initialize mode. Disabling pxc_strict_mode checks 2017-04-13T14:53:02.877589Z 0 [ERROR] --initialize specified but the data directory has files in it. Aborting. 2017-04-13T14:53:02.877618Z 0 [ERROR] Aborting