mysql: variable master_host empty on slave reboot

Hello,

I'm having trouble with a MariaDB cluster (2 nodes, master-slave) on Debian 11.
I don't know what to do anymore.

**Environment:**

Node1:
OS: Debian 11
Kernel: 5.10.0-21-amd64 #1 SMP Debian 5.10.162-1 (2023-01-21)
Versions: resource-agents (4.7.0-1), pacemaker (2.0.5-2), corosync (3.1.2-2), mariadb (10.5.18-0+deb11u1)

Node2:
OS: Debian 11
Kernel: 5.10.0-21-amd64 #1 SMP Debian 5.10.162-1 (2023-01-21)
Versions: resource-agents (4.7.0-1), pacemaker (2.0.5-2), corosync (3.1.2-2), mariadb (10.5.18-0+deb11u1)

crm configure show as attachment:
[crm_configure_show.txt](https://github.com/ClusterLabs/resource-agents/files/10571196/crm_configure_show.txt)

**Problem:**

When I restart Node2 (which is a slave), it goes up correctly in the cluster:

```
$ crm status
Cluster Summary:
* Stack: corosync
* Current DC: Node1 (version 2.0.5-ba59be7122) - partition with quorum
* Last updated: Thu Jan 26 12:04:57 2023
* Last change: Thu Jan 26 11:39:58 2023 by root via cibadmin on Node2
* 2 nodes configured
* 3 resource instances configured

Node List:
* Online: [ Node1 Node2 ]

Full List of Resources:
* VIP (ocf::heartbeat:IPaddr2): Started Node1
* Clone Set: MYSQLREPLICATOR [MYSQL] (promotable):
* Masters: [ Node1 ]
* Slaves: [ Node2 ]
```

But it does not retrieve the replication information. (SHOW SLAVE STATUS; returns nothing)
In the Node2 logs, I can see this message that explains that replication is not taking place:

```
Jan 25 16:29:38 mysql(MYSQL)[22862]: INFO: No MySQL master present - clearing replication state
Jan 25 16:29:39 mysql(MYSQL)[22862]: WARNING: MySQL Slave IO threads currently not running.
Jan 25 16:29:39 mysql(MYSQL)[22862]: ERROR: MySQL Slave SQL threads currently not running.
Jan 25 16:29:39 mysql(MYSQL)[22862]: ERROR: See for details
Jan 25 16:29:39 mysql(MYSQL)[22862]: ERROR: ERROR 1200 (HY000) at line 1: Misconfigured slave: MASTER_HOST was not set; Fix in config file or with CHANGE MASTER TO
```

From what I see, when activating the trace mode, the variable master_host is empty:

```
+ [ -n ]
+ [ 0 -eq 0 ]
+ [ 1 -a ! -z ]
+ return 0
+ echo
+ tr -d
+ master_host=
+ [ -a != Node2 ]
+ ocf_log info No MySQL master present - clearing replication state

```

Because the environment variables are also empty and especially "OCF_RESKEY_CRM_meta_notify_master_uname":

```
OCF_RESKEY_CRM_meta_notify=true
OCF_RESKEY_CRM_meta_notify_active_resource=
OCF_RESKEY_CRM_meta_notify_active_uname=
OCF_RESKEY_CRM_meta_notify_all_uname=Node1 Node2
OCF_RESKEY_CRM_meta_notify_available_uname=Node2 Node1
OCF_RESKEY_CRM_meta_notify_demote_resource=
OCF_RESKEY_CRM_meta_notify_demote_uname=
OCF_RESKEY_CRM_meta_notify_inactive_resource=MYSQL:0 MYSQL:1
OCF_RESKEY_CRM_meta_notify_master_resource=
OCF_RESKEY_CRM_meta_notify_master_uname=
OCF_RESKEY_CRM_meta_notify_promote_resource=
OCF_RESKEY_CRM_meta_notify_promote_uname=
OCF_RESKEY_CRM_meta_notify_slave_resource=
OCF_RESKEY_CRM_meta_notify_slave_uname=
OCF_RESKEY_CRM_meta_notify_start_resource=MYSQL:0
OCF_RESKEY_CRM_meta_notify_start_uname=Node2
OCF_RESKEY_CRM_meta_notify_stop_resource=
OCF_RESKEY_CRM_meta_notify_stop_uname=
```

As it is a production environment, I performed a bare metal restore of these machines on 2 test machines and I have no problem…
In production, there is a lot of writing but the servers are far from being saturated.

Pacemaker log before and after reboot on slave:
[log_pacemaker.txt](https://github.com/ClusterLabs/resource-agents/files/10571249/log_pacemaker.txt)

Thank you in advance for all the help you can give me.

Best regards

Start with the attached crm_configure_show.txt and log_pacemaker.txt, then trace the MYSQL resource agent's notification handling and how it derives master_host after a slave reboot. Reproduce the Node2 restart scenario and verify that SHOW SLAVE STATUS returns replication information without the MASTER_HOST error.

Written by the indexing model from the issue text.