[Solved] Mysql Build Error: [ERROR] Slave I/O for channel ‘‘: error connecting to master

Project scenario:

mysql5. 7 build dual master replication:
host a: production library
host B: create a new empty library
operating system: centos7

Problem description

tip: describe the problems encountered in the project here:
start slave on host B:
change master to master_ host=‘’,master_ port=3306,master_ user=‘repl’,master_ password=‘*****’,master_ log_ file=‘mysql-bin. 000017’,master_ log_ pos=****;
start slave replication is normal;

Enable slave on host a:
change master to master_ host=‘’,master_ port=3307,master_ user=‘repl’,master_ password=‘*****’,master_ log_ file=‘mysql-bin. 1234’,master_ log_ pos=****;
after start save, show slave status reports the following error:
error connecting to master‘ [email protected] : 3307 ‘- retry time: 60 retries: 6
check that there are no other meaningful logs under/var/log/messages

Cause analysis:

Troubleshooting route:
1 Log in to host B MySQL on host a: MySQL – U repl – p ‘*****’ – P 3307 – H normal – eliminate account and password errors
2. Check the permission of the replication account on host B, show grants for repl @ ‘%’ and find that it has the permission of replication slave and replication client – eliminate the permission problem
I tried to create a new account, but it didn’t work to restart the service.
finally, it is found that SELinux is not related
check SELinux status:

 [[email protected] ~]# getenforce
Enforcing(means selinux does not close)


Close SELinux:
I Temporary shutdown
enter the command setenforce = 0 (it will be invalid after restarting the machine)
check SELinux status:

[[email protected] ~]# getenforce
	Permissive(means close successfully)

II Permanently close
open the /etc/selinux/config file and modify SELINUX=DISABLED (the server needs to be restarted to take effect);

re-change master and then restart to copy successfully

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