利用数据库自定义并发 bunket 功能

场景

防止由于停电后大规模 HV 启动, 导致 OPENSTACK NEUTRON SERVER 服务由于 HV 并发注册量太大而拒绝服务

思路

1. 数据库中创建表, COUNT, 列 id int 表中定义并发量, (例如 30)

2. 当 HV 启动时候, 假如需要启动 NEUTRON 服务, 则先要向 COUNT 表中获得信息,

假如 count.id 中值 > 1 , 则可以获得启动权限, 并 count.id -1,

当 neutron 服务注册完成, 则向数据库执行 count.id +1

参考表结构

用于做 bunket 算法
create table count ( id int ) engine innodb;

mysql> desc count;
+-------+---------+------+-----+---------+-------+
| Field | Type    | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| id    | int(11) | YES  |     | NULL    |       |
+-------+---------+------+-----+---------+-------+
1 row in set (0.00 sec)

用于做数据记录的表, 可有可无

CREATE TABLE node (
id int(11) DEFAULT NULL,
name varchar(50) DEFAULT NULL
) ENGINE=InnoDB;

mysql> desc node;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id    | int(11)     | YES  |     | NULL    |       |
| name  | varchar(50) | YES  |     | NULL    |       |
+-------+-------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

参考存储过程

获得 bunket 数据的存储过程

drop procedure startup;

delimiter //
create procedure startup( in d varchar(50), out n varchar(5) )
begin
declare a int;
declare b int;
declare c varchar(50);
select id into a from compute.count for update;
set autocommit=0;
if a > 0
then
select name into c from compute.node where name=d;
if c is null
then
set b=a-1;
insert into compute.node values ( a, d);
update compute.count set id=b;
set n='ready';
else
set n='faile';
end if;
end if;
commit;
select n from dual;
end
//

delimiter ;

完成neutron 注册后回调 bunket 的存储过程

drop procedure startend;
delimiter //
create procedure startend( in d varchar(50) )
begin
declare a int;
declare b int;
declare c varchar(50);
select id into a from compute.count for update;
set autocommit=0;
set b=a+1;
update compute.count set id=b;
delete from compute.node where name=d;
commit;
end
//

delimiter ;

参加 compute 节点启动时候的启动脚本

#!/bin/bash
#
#

source params   <--- 注意:  公共变量,  公共函数存放的位置,  下文中缺的函数与变量都来自这里,  与整个算法无关, 忽略吧

service_type=compute

sqlstartpath='/root/manager/get_status.sql'
sqlendpath='/root/manager/end.sql'
status='faile'

if [ ! -d '/root/manager/' ]
then
mkdir -p '/root/manager'
fi

cat <<EOF  > $sqlstartpath
set @a='ok';
use compute;
call startup('$hostname',@a);
EOF

cat <<EOF > $sqlendpath
use compute;
call startend('$hostname');
EOF

if [ ! -f "/usr/bin/mysql" ]
then
yum install -y mysql > /dev/null 2>&1
fi

while [ "$status" != "ready" ]
do
status=`mysql -h $sql_server -u $sql_user -p"$sql_passwd" --skip-column-names $sql_db -e "source $sqlstartpath;"`
if [ "$status" != "ready" ]
then
sleep 5
fi
done

start_server messagebus messagebus
start_server libvirtd libvirtd
start_server openstack-nova-compute nova_compute
start_server neutron-openvswitch-agent openvswitch_agent
start_server openvswitch openvswitch
start_server openstack-ceilometer-compute ceilometer_compute

mysql -h $sql_server -u $sql_user -p"$sql_passwd" --skip-column-names $sql_db -e "source $sqlendpath;"