标签：mysql mha
bmildren edited this page on 27 Jan 2016 · 1 revision
MHA consists of MHA Manager and MHA Node packages. MHA Manager runs on a manager server, and MHA Node runs on each MySQL server. MHA Node programs do not run always, but are invoked from MHA manager programs when needed (at configuration check, failover, etc). Both MHA Manager and MHA Node are written in Perl.
MHA Node and MHA Manager can be downloaded from "Downloads" section. These are stable packages.
If you want to try development source trees, check out GitHub source trees. MHA Manager is hosted here, and MHA Node is hosted here.
MHA Node has scripts and dependent perl modules that do the following.
save_binary_logs: Saving and copying dead master‘s binary logs
apply_diff_relay_logs: Identifying differential relay log events and applying all necessary log events
purge_relay_logs: Purging relay log files
You need to install MHA Node to all MySQL servers (both master and slave). You also need to install MHA Node on a management server because MHA Manager modules internally depend on MHA Node modules. MHA Manager internally connects to managed MySQL servers via SSH and executes MHA Node scripts. MHA Node does not depend on any external Perl modules except DBD::mysql so you should be able to install easily.
On RHEL/CentOS distribution, you can install MHA Node rpm package as below.
## If you have not installed DBD::mysql, install it like below, or install from source. # yum install perl-DBD-MySQL ## Get MHA Node rpm package from "Downloads" section. # rpm -ivh mha4mysql-node-X.Y-0.noarch.rpm
On Ubuntu/Debian distribution, you can install MHA Node deb package as below.
## If you have not installed DBD::mysql, install it like below, or install from source. # apt-get install libdbd-mysql-perl ## Get MHA Node deb package from "Downloads" section. # dpkg -i mha4mysql-node_X.Y_all.deb
You can also install MHA Node from source.
## Install DBD::mysql if not installed $ tar -zxf mha4mysql-node-X.Y.tar.gz $ perl Makefile.PL $ make $ sudo make install
MHA Manager has administrative command line programs such as masterha_manager, masterha_master_switch, etc, and dependent Perl modules. MHA Manager depends on the following Perl modules. You need to install them before installing MHA Manager. Do not forget to install MHA Node.
MHA Node package
DBD::mysql
Config::Tiny
Log::Dispatch
Parallel::ForkManager
Time::HiRes (included from Perl v5.7.3)
On RHEL/CentOS distribution, you can install MHA Manager rpm package as below.
## Install dependent Perl modules # yum install perl-DBD-MySQL # yum install perl-Config-Tiny # yum install perl-Log-Dispatch # yum install perl-Parallel-ForkManager ## Install MHA Node, since MHA Manager uses some modules provided by MHA Node. # rpm -ivh mha4mysql-node-X.Y-0.noarch.rpm ## Finally you can install MHA Manager # rpm -ivh mha4mysql-manager-X.Y-0.noarch.rpm
On Ubuntu/Debian distribution, you can install MHA Manager deb package as below.
## Install dependent Perl modules # apt-get install libdbd-mysql-perl # apt-get install libconfig-tiny-perl # apt-get install liblog-dispatch-perl # apt-get install libparallel-forkmanager-perl ## Install MHA Node, since MHA Manager uses some modules provided by MHA Node. # dpkg -i mha4mysql-node_X.Y_all.deb ## Finally you can install MHA Manager # dpkg -i mha4mysql-manager_X.Y_all.deb
You can also install MHA Manager from source.
## Install dependent Perl modules # MHA Node (See above) # Config::Tiny ## perl -MCPAN -e "install Config::Tiny" # Log::Dispatch ## perl -MCPAN -e "install Log::Dispatch" # Parallel::ForkManager ## perl -MCPAN -e "install Parallel::ForkManager" ## Installing MHA Manager $ tar -zxf mha4mysql-manager-X.Y.tar.gz $ perl Makefile.PL $ make $ sudo make install
bmildren edited this page on 27 Jan 2016 · 1 revision
To make MHA work, you have to create a configuration file and set parameters. Parameters include hostname of each MySQL server, MySQL username and password, working directory name, etc. The whole parameters are described at Parameters page.
The below is an example configuration file.
manager_host$ cat /etc/app1.cnf
[server default] # mysql user and password user=root password=mysqlpass # working directory on the manager manager_workdir=/var/log/masterha/app1 # manager log file manager_log=/var/log/masterha/app1/app1.log # working directory on MySQL servers remote_workdir=/var/log/masterha/app1 [server1] hostname=host1 [server2] hostname=host2 [server3] hostname=host3
All parameters must follow "param=value" syntax. For example, the below parameter setting is incorrect.
[server1] hostname=host1 # incorrect: must be "no_master=1" no_master
Application-scope parameters should be written in [server default] block. In [serverN]
blocks, you should set local-scope parameters. hostname is mandatory
local-scope parameter so has to be written here. Block name should start
from "server". Internally server configurations are sorted by block
name, and sorted order matters when MHA decides new master (See FAQ for details).
If you plan to manage two or more MySQL applications ((master, slaves) pairs) from a single manager server, creating a global configuration file makes it much easier to configure. Once you write parameters in the global configuration file, you do not need to set parameters for each application. If you create a file at /etc/masterha_default.cnf, MHA Manager scripts automatically reads the file as a global configuration file.
You can set application scope parameters in the global configuration file. For example, if MySQL administrative user and password are identical on all MySQL servers, you can set "user" and "password" here.
Global configuration file (/etc/masterha_default.cnf)
[server default] user=root password=rootpass ssh_user=root master_binlog_dir= /var/lib/mysql remote_workdir=/data/log/masterha secondary_check_script= masterha_secondary_check -s remote_host1 -s remote_host2 ping_interval=3 master_ip_failover_script=/script/masterha/master_ip_failover shutdown_script= /script/masterha/power_manager report_script= /script/masterha/send_master_failover_mail
These parameters are applied to all applications monitored by MHA Manager running on the host.
Application configuration file should be written separately. The below example is configuraing app1 (host1-4) and app2 (host11-14).
app1:
manager_host$ cat /etc/app1.cnf
[server default] manager_workdir=/var/log/masterha/app1 manager_log=/var/log/masterha/app1/app1.log [server1] hostname=host1 candidate_master=1 [server2] hostname=host2 candidate_master=1 [server3] hostname=host3 [server4] hostname=host4 no_master=1
In the above case, MHA Manager generates working files (including status files) under /var/log/masterha/app1, and generates log file at /var/log/masterha/app1/app1.log. You need to set unique directory/file names when monitoring other applications.
app2:
manager_host$ cat /etc/app2.cnf
[server default] manager_workdir=/var/log/masterha/app2 manager_log=/var/log/masterha/app2/app2.log [server1] hostname=host11 candidate_master=1 [server2] hostname=host12 candidate_master=1 [server3] hostname=host13 [server4] hostname=host14 no_master=1
If you set same parameters on both global configuration file and application configuration file, the latter (application configuration) is used.
Starting from MHA version 0.56, MHA supports new section [binlogN]. In binlog section, you can define mysqlbinlog streaming servers.
When MHA does GTID based failover, MHA checks binlog servers, and if
binlog servers are ahead of other slaves, MHA applies differential
binlog events to the new master before recovery. When MHA does non-GTID
based (traditional) failover, MHA ignores binlog servers.
Below is an example configuration.
manager_host$ cat /etc/app1.cnf
[server default] # mysql user and password user=root password=mysqlpass # working directory on the manager manager_workdir=/var/log/masterha/app1 # manager log file manager_log=/var/log/masterha/app1/app1.log # working directory on MySQL servers remote_workdir=/var/log/masterha/app1 [server1] hostname=host1 [server2] hostname=host2 [server3] hostname=host3 [binlog1] hostname=binlog_host1 [binlog2] hostname=binlog_host2
转自： https://github.com/yoshinorim/mha4mysql-manager/wiki
标签：mysql mha
原文地址：http://132408.blog.51cto.com/122408/1896843
