Problem joining the secondary(slave) server to the cluster (Percona XtraDB Cluster 5.7.35-38-57 - CentOS7)

Hello everyone!
I have Percona XtraDB Cluster 5.7.35-35-57 installed on 3 identical VPS on CentOS 7.
After shutting down all 3 servers in the cluster, I restored the database to the primary (master) server that was backed up by Percona XtraBackup from the production stand-alone Percona MySQL 5.7.23-23 server.

I successfully started the primary server using the command: systemctl start mysql@bootstrap.service as staded in the documentation, but my secondary servers (slave 1 and 2) do not want to run and their journalctl -xe displays the following messages:
(I run the secondary servers with a command: systemctl start mysql)

-- Unit systemd-hostnamed.service has finished starting up.
--
-- The start-up result is done.
Dec 21 10:37:37 server2-xtradb polkitd[690]: Registered Authentication Agent for unix-process:28332:41737902 (system bus name :1.307 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object path /org/freedesktop/PolicyKit1/Authenticati
Dec 21 10:37:37 server2-xtradb systemd[1]: Starting Percona XtraDB Cluster...
-- Subject: Unit mysql.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit mysql.service has begun starting up.
Dec 21 10:37:50 server2-xtradb mysqld_safe[28489]: 2021-12-21T09:37:50.161341Z mysqld_safe Logging to '/var/log/mysqld.log'.
Dec 21 10:37:50 server2-xtradb mysqld_safe[28489]: 2021-12-21T09:37:50.168908Z mysqld_safe Logging to '/var/log/mysqld.log'.
Dec 21 10:37:50 server2-xtradb mysqld_safe[28489]: 2021-12-21T09:37:50.240866Z mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
Dec 21 10:37:50 server2-xtradb mysqld_safe[28489]: 2021-12-21T09:37:50.256377Z mysqld_safe Skipping wsrep-recover for empty datadir: /var/lib/mysql
Dec 21 10:37:50 server2-xtradb mysqld_safe[28489]: 2021-12-21T09:37:50.260924Z mysqld_safe Assigning 00000000-0000-0000-0000-000000000000:-1 to wsrep_start_position
Dec 21 10:37:50 server2-xtradb systemd[1]: mysql.service: main process exited, code=exited, status=1/FAILURE
Dec 21 10:37:51 server2-xtradb mysql-systemd[28490]: /usr/bin/mysql-systemd: line 140: kill: (28489) - No such process
Dec 21 10:37:51 server2-xtradb systemd[1]: mysql.service: control process exited, code=exited status=1
Dec 21 10:37:51 server2-xtradb mysql-systemd[28490]: ERROR! mysqld_safe with PID 28489 has already exited: FAILURE
Dec 21 10:37:51 server2-xtradb mysql-systemd[29219]: WARNING: mysql pid file /var/run/mysqld/mysqld.pid empty or not readable
Dec 21 10:37:51 server2-xtradb systemd[1]: mysql.service: control process exited, code=exited status=2
Dec 21 10:37:51 server2-xtradb mysql-systemd[29219]: ERROR! mysql already dead
Dec 21 10:37:51 server2-xtradb mysql-systemd[29247]: WARNING: mysql pid file /var/run/mysqld/mysqld.pid empty or not readable
Dec 21 10:37:51 server2-xtradb mysql-systemd[29247]: WARNING: mysql may be already dead
Dec 21 10:37:51 server2-xtradb systemd[1]: Failed to start Percona XtraDB Cluster.
-- Subject: Unit mysql.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit mysql.service has failed.
--
-- The result is failed.
Dec 21 10:37:51 server2-xtradb systemd[1]: Unit mysql.service entered failed state.
Dec 21 10:37:51 server2-xtradb systemd[1]: mysql.service failed.
Dec 21 10:37:51 server2-xtradb polkitd[690]: Unregistered Authentication Agent for unix-process:28332:41737902 (system bus name :1.307, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) (disconnected from bus)

mysqld.log from secundary server:

2021-12-21T09:37:37.130318Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2021-12-21T09:37:37.130565Z 0 [Warning] WSREP: Node is running in bootstrap/initialize mode. Disabling pxc_strict_mode checks
2021-12-21T09:37:37.140951Z 0 [Warning] No argument was provided to --log-bin, and --log-bin-index was not used; so replication may break when this MySQL server acts as a master and has his hostname changed!! Please use '--log-bin=s$
2021-12-21T09:37:38.410257Z 0 [Warning] InnoDB: New log files created, LSN=45790
2021-12-21T09:37:38.674920Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
2021-12-21T09:37:38.771421Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: a2f09179-6241-11ec-923e-00155d1f8e13.
2021-12-21T09:37:38.774305Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.
2021-12-21T09:37:40.125957Z 0 [Warning] A deprecated TLS version TLSv1 is enabled. Please use TLSv1.2 or higher.
2021-12-21T09:37:40.126033Z 0 [Warning] A deprecated TLS version TLSv1.1 is enabled. Please use TLSv1.2 or higher.
2021-12-21T09:37:40.127559Z 0 [Warning] CA certificate ca.pem is self signed.
2021-12-21T09:37:40.234314Z 1 [Note] A temporary password is generated for root@localhost: 

by logs the problem seems to be in creating a mysql PID.
I tried everything I could find on the internet.
Thanks in advance for your help.

Any help would be welcome.

1 Like

Ensure that this path exists and is owned by mysql user. You need to include more of mysql’s error log in your next post as what you have above shows no issues.

1 Like

thanks for the reply, but /var/run/mysqld/ already has mysql permissions.

Since my primary server was successfully started, I would try to copy the data from it to one of the secondary servers. Is there a command for this because I could not find it in the documentation or do I need to use the Percona XtraBackup tool?

Thanks in advance for your help.

1 Like

No, this is not how you set up PXC. You need to figure out why your node2 is not starting. When node2 starts correctly, it will automatically get the necessary data from node1. You need to provide more logs from node2 so we can see what is really going wrong. What OS is this?

1 Like