One of the many ways to restore a replication in case of mysql-bin log loss is to use Percona Xtrabackup utility.
The advantage of using this method is that it does not require a MASTER server stop. The only condition is having binary logging enabled.
1) Install Xtrabackup utility
root@vagrant-ubuntu-trusty-64-test1111:~# apt install percona-xtrabackup
2) Prepare data for copying and create a database backup
To do that, create a new directory and copy files to it
root@vagrant-ubuntu-trusty-64-test1111:~/mysql# innobackupex --user=root --password=root /home/vagrant/mysql/
In the directory created, a new one with the current date will appear
3) When a backup is created, data is not yet ready for the restore. The logs to be restored may contain cancelled transactions. It is required to apply a change log to a data file
root@vagrant-ubuntu-trusty-64-test1111:~/mysql# innobackupex --user=root --password=root --apply-log /home/vagrant/mysql/2018-10-03_08-07-34/
When a backup is ready, copy data files to a SLAVE server
4) On the SLAVE server, stop mysql service and copy data to mysql directory.
root@vagrant-ubuntu-trusty-64-test4444:~/mysql# service mysql stop root@vagrant-ubuntu-trusty-64-test4444:~/mysql# mv /var/lib/mysql /var/lib/mysql.old root@vagrant-ubuntu-trusty-64-test4444:~/mysql# cp /home/vagrant/mysql/2018-10-03_08-07-34/ /var/lib/mysql root@vagrant-ubuntu-trusty-64-test4444:~/mysql# chown -R mysql:mysql /var/lib/mysql root@vagrant-ubuntu-trusty-64-test4444:~/mysql# service mysql start
5) Open mysql console, get the binary log's location and name. After that, configure replication on the SLAVE server.
root@vagrant-ubuntu-trusty-64-test4444:~/mysql# cat /home/vagrant/mysql/2018-10-03_08-07-34/xtrabackup_binlog_info mysql-bin.002454 9311320
mysql> STOP SLAVE; mysql> CHANGE MASTER TO MASTER_HOST='<ip_server1>', MASTER_USER='replication', MASTER_PASSWORD='password', MASTER_LOG_FILE='mysql-bin.002454', MASTER_LOG_POS=9311320; mysql> START SLAVE;
Check if replication is working
mysql> SHOW SLAVE STATUS\G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: <ip_server1>
Master_User: replication
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.002455
Read_Master_Log_Pos: 89717415
Relay_Log_File: mysqld-relay-bin.000004
Relay_Log_Pos: 89717561
Relay_Master_Log_File: mysql-bin.002455
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table: