Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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1.4.0, 1.4.1
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None
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CentOS release 6.7 (Final)
kernel: 2.6.32-573.18.1.el6.x86_64
Galera Cluster / MariaDB: 5.5.46-MariaDB-wsrep MariaDB Server, wsrep_25.12.r4f81026
Description
We have 12 MaxScale (version 1.3.0) servers running at the moment, behind HAproxy and connected to a Galera Cluster of 4 nodes (1 master, 3 slaves)
I've put 1 server in maintenance, so I could try to update MaxScale to 1.4.1.
Situation before updating (and running 1.3.0):
# maxadmin -pmariadb list servers
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Servers.
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-------------------+-----------------+-------+-------------+--------------------
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Server | Address | Port | Connections | Status
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-------------------+-----------------+-------+-------------+--------------------
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db-03 | 192.168.120.74 | 3306 | 22 | Master, Synced, Running
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db-04 | 192.168.120.95 | 3306 | 23 | Slave, Synced, Running
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db-05 | 192.168.120.96 | 3306 | 22 | Slave, Synced, Running
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db-06 | 192.168.120.97 | 3306 | 23 | Slave, Synced, Running
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-------------------+-----------------+-------+-------------+--------------------
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After updating (running 1.4.1)
# maxadmin -pmariadb list servers
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Servers.
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-------------------+-----------------+-------+-------------+--------------------
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Server | Address | Port | Connections | Status
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-------------------+-----------------+-------+-------------+--------------------
|
db-03 | 192.168.120.74 | 3306 | 1 | Slave, Synced, Running
|
db-04 | 192.168.120.95 | 3306 | 1 | Slave, Synced, Running
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db-05 | 192.168.120.96 | 3306 | 1 | Slave, Synced, Running
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db-06 | 192.168.120.97 | 3306 | 1 | Master, Synced, Running
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-------------------+-----------------+-------+-------------+--------------------
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Whatever we do, we can't get db-03 to be Master again. It will always change back to db-06.
db-03 has the lowest wsrep_local_index, so it should be elected as Master, right?
We've noticed some difference in the "Node Id" from "show servers" output. On 1.3.0, the Node Id = 0 and on 1.4.1 the Node Id = -1
On 1.3.0:
# maxadmin -pmariadb show servers | egrep 'Id|Server '
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Server 0x25903f0 (db-03)
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Server Version: 5.5.45-MariaDB-wsrep
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Node Id: 0
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Master Id: -1
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Server 0x25902b0 (db-04)
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Server Version: 5.5.46-MariaDB-wsrep
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Node Id: 3
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Master Id: -1
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Server 0x2590190 (db-05)
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Server Version: 5.5.46-MariaDB-wsrep
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Node Id: 2
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Master Id: -1
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Server 0x258ffc0 (db-06)
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Server Version: 5.5.46-MariaDB-wsrep
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Node Id: 1
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Master Id: -1
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On 1.4.1:
# maxadmin -pmariadb show servers | egrep 'Id|Server '
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Server 0x87efe0 (db-03)
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Server Version: 5.5.45-MariaDB-wsrep
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Node Id: -1
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Master Id: -1
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Server 0x87eea0 (db-04)
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Server Version: 5.5.46-MariaDB-wsrep
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Node Id: 3
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Master Id: -1
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Server 0x87ed60 (db-05)
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Server Version: 5.5.46-MariaDB-wsrep
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Node Id: 2
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Master Id: -1
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Server 0x87eb70 (db-06)
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Server Version: 5.5.46-MariaDB-wsrep
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Node Id: 1
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Master Id: -1
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The logfile shows some errors:
2016-04-01 09:50:36 error : Couldn't find suitable Master from 4 candidates.
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2016-04-01 09:50:36 error : Failed to create new router session for service 'Splitter Service'. See previous errors for more details.
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When we downgrade back to 1.3.0, server db-03 is Master again.