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The guide assumes that you have SSH access to the Squirro servers and the password to access mysql.

1. Identify the current master

2. For each broken slave, stop the Squirro cluster service:

   $ sudo monit stop

   Code Block
   sudo systemctl stop sqclusterd

3. Ensure you have a running system with one cluster node.

4. At the master:

   Code Block
   mysql> RESET MASTER;

   Query OK,

    

   0

    

   rows affected (0.14

    

   sec)

    

   mysql> FLUSH TABLES WITH READ LOCK;

   Query OK,

    

   0

    

   rows affected (0.00

    

   sec)

    

   mysql> SHOW MASTER STATUS;

   +------------------+----------+--------------+------------------+

   |

    File             | Position |

   File | Position | Binlog_Do_DB | Binlog_Ignore_DB |

   +------------------+----------+--------------+------------------+

   | mysql-bin.000001

    |     12268 |              |                  |

   | 12268 | | | +------------------+----------+--------------+------------------+

   1

    

   row

    

   in

    

   set

    

   (0.00

    

   sec)

    
   mysql>
    
    
   $ mkdir 

   mysql> exit $ mkdir /var/lib/squirro/cluster/mysql/<date>

   $ mysqldump

    

   --host=127.0.0.1

    

   --port=3306

    

   --user=cluster

    

   --password=$(PASSWORD)

    

   --all-databases

    

   --master-data

    

   --single-transaction

    

   --result-file

    

   /var/lib/squirro/cluster/mysql/<date>/dump.db

    

   $ mysql -u root -p

   mysql> UNLOCK TABLES;

    

   $ cd

    

   /var/lib/squirro/cluster/mysql/<date>/

   $ gzip dump.db

   $ scp dump.db.gz $(SSH_USER)@$(IP_SLAVE1):/tmp/

   $ scp dump.db.gz $(SSH_USER)@$(IP_SLAVE2):/tmp/

5. On each slave:

   Code Block
   $ mkdir

    

   /var/lib/squirro/cluster/mysql/restore-<date>

   $ mv

    

   /tmp/dump.db.gz

    

   /var/lib/squirro/cluster/mysql/restore-<date>

   $ cd

    

   /var/lib/squirro/cluster/mysql/restore-<date>

   $ gunzip dump.db.gz

    

   mysql> stop slave;

    

   $ mysql

    

   --host=127.0.0.1

    

   --port=3306

    

   --user=cluster

    

   --password=$(PASSWORD)

    

   -e

    

   "source dump.db;"

   $ mysql -u root -p

   mysql> RESET SLAVE;

   mysql> change master to master_user='repl';

   mysql> show slave status\G;

       

   -->

    

   if

    

   master_host does

    

   not

    

   point to current master, e.g.: mysql> change master to master_host

    

   =

    

   "$(IP_MASTER)";

    

   mysql> CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS=12268;

               

   --> ensure that the position matches the value

    

   from

    

   SHOW MASTER STATUS; above

   mysql> START SLAVE;

   mysql> show slave status\G;

         

   --> ensure that Slave_IO_Running:

   Yes  and   

   Yes and Slave_SQL_Running: Yes

    
   $ monit start sqclusterd
   $ monit

   $ sudo systemctl start sqclusterd $ monit summary