MySQL：Pacemaker 无法将出现故障的主服务器启动为新的从服务器？

Question

尤里卡！

我们俩都忘了非常非常重要的日志文件，它是...... /var/log/mysqld.log：

socket: '/var/lib/mysql/mysql.sock'  port: 3306  MySQL Community Server (GPL) by Atomicorp
[Note] Slave SQL thread initialized, starting replication in log 'mysql-bin.000082' at position 58569, relay log './mysqld-relay-bin.000002' position: 58715
[Note] Slave I/O thread: connected to master '[email protected]:3306',replication started in log 'mysql-bin.000082' at position 58569
[Warning] Aborted connection 10 to db: 'unconnected' user: 'test_user' host: 'localhost' (init_connect command failed)
[Warning] The MySQL server is running with the --read-only option so it cannot execute this statement
[Note] /usr/libexec/mysqld: Normal shutdown

你可以猜到，我通过结合 binlog 和init-connect：

init_connect = "INSERT INTO audit.accesslog (connect_time, user_host, connection_id) VALUES (NOW(), CURRENT_USER(), CONNECTION_ID());"

但serving-6192在作为从属设备启动时设置为只读，然后当 Pacemaker 使用以下命令执行监视操作test_user：

    # Check for test table
    ocf_run -q $MYSQL $MYSQL_OPTIONS_TEST \
        -e "SELECT COUNT(*) FROM $OCF_RESKEY_test_table"

init_connect命令失败，出现上述错误：

MySQL 服务器正在使用该--read-only选项运行，因此无法执行此语句

解决方案是，我应该init_connect在初始化监视操作之前将选项设置为空字符串（在将节点提升为主节点时不要忘记将其改回）

对于正在使用事件调度程序：还请注意，在将从服务器提升为主服务器时必须启用它：

set_event_scheduler() {
    local es_val
    if ocf_is_true $1; then
        es_val="on"
    else
        es_val="off"
    fi
    ocf_run $MYSQL $MYSQL_OPTIONS_REPL \
        -e "SET GLOBAL event_scheduler=${es_val}"
}

get_event_scheduler() {
    # Check if event-scheduler is set
    local event_scheduler_state

    event_scheduler_state=`$MYSQL $MYSQL_OPTIONS_REPL \
        -e "SHOW VARIABLES" | grep event_scheduler | awk '{print $2}'`

    if [ "$event_scheduler_state" = "ON" ]; then
        return 0
    else
        return 1
    fi
}

mysql_promote() {
    local master_info

    if ( ! mysql_status err ); then
        return $OCF_NOT_RUNNING
    fi
    ocf_run $MYSQL $MYSQL_OPTIONS_REPL \
        -e "STOP SLAVE"

    # Set Master Info in CIB, cluster level attribute
    update_data_master_status
    master_info="$(get_local_ip)|$(get_master_status File)|$(get_master_status Position)"
    ${CRM_ATTR_REPL_INFO} -v "$master_info"
    rm -f $tmpfile

    set_read_only off || return $OCF_ERR_GENERIC
    set_event_scheduler on || return $OCF_ERR_GENERIC

降级时也不要忘记将其关闭：

    'pre-demote')
        # Is the notification for our set
        notify_resource=`echo $OCF_RESKEY_CRM_meta_notify_demote_resource|cut -d: -f1`
        my_resource=`echo $OCF_RESOURCE_INSTANCE|cut -d: -f1`
        if [ $notify_resource != ${my_resource} ]; then
            ocf_log debug "Notification is not for us"
            return $OCF_SUCCESS
        fi

        demote_host=`echo $OCF_RESKEY_CRM_meta_notify_demote_uname|tr -d " "`
        if [ $demote_host = ${HOSTNAME} ]; then
            ocf_log info "post-demote notification for $demote_host"
            set_read_only on
            set_event_scheduler off

干杯，

Answer 1