keepalived主从切换试验：
1、先搭建192.168.1.20与192.168.1.21的主主架构     192.168.1.76为VIP
2、在2机都安装keepalived
  1.  tar -zxvf keepalived-1.2.13.tar.gz 
  2.  cd keepalived-1.2.13
  3.  ./configure -prefix=/usr/local/keepalived
  4.  make
  5. make install
  6.  [root@likun keepalived-1.2.13]# cat /opt/mysql/mysql.sh 
  7. #!/bin/sh
  8. pkill keepalived
  9. [root@likun keepalived-1.2.13]# chmod +x /opt/mysql/mysql.sh
3、配置20机器的keepalived配置文件
  1. [root@likun keepalived-1.2.13]# cat /usr/local/keepalived/etc/keepalived.conf
  2. !ConfigurationFilefor keepalived 
  3.  
  4. global_defs { 
  5.    notification_email { 
  6.      likun@163.com 
  7.    } 
  8.    router_id mysql-ha 
  9. } 
  10.  
  11. vrrp_instance VI_20 { 
  12.     state BACKUP
  13.     interface eth0 
  14.     virtual_router_id 20
  15.     priority 90
  16.     advert_int 1 
  17.     nopreempt        
  18.     authentication { 
  19.         auth_type PASS 
  20.         auth_pass 1111  
  21.     } 
  22.     virtual_ipaddress {   
  23.         192.168.1.76
  24.     } 
  25. } 
  26.  
  27. virtual_server 192.168.1.763306{ 
  28.     delay_loop 2 
  29.     lb_algo wrr 
  30.     lb_kind DR 
  31.     persistence_timeout 60 
  32.     protocol TCP 
  33.  
  34.     real_server 192.168.1.203306{
  35.         weight 3 
  36.         notify_down /opt/mysql/mysql.sh 
  37.             TCP_CHECK { 
  38.             connect_timeout 10 
  39.             nb_get_retry 3 
  40.             delay_before_retry 3 
  41.             connect_port 3306
  42.         } 
  43.     } 
  44. } 
4、配置21机器的keepalived配置文件
  1. !ConfigurationFilefor keepalived 
  2.  
  3. global_defs { 
  4.    notification_email { 
  5.      likun@163.com 
  6.    } 
  7.    router_id mysql-ha 
  8. } 
  9.  
  10. vrrp_instance VI_21 { 
  11.     state BACKUP
  12.     interface eth0 
  13.     virtual_router_id 20        --注意2边要一致
  14.     priority 100
  15.     advert_int 1 
  16.     nopreempt        
  17.     authentication { 
  18.         auth_type PASS 
  19.         auth_pass 1111  
  20.     } 
  21.     virtual_ipaddress {   
  22.         192.168.1.76
  23.     } 
  24. } 
  25.  
  26. virtual_server 192.168.1.763306{ 
  27.     delay_loop 2 
  28.     lb_algo wrr 
  29.     lb_kind DR 
  30.     persistence_timeout 60 
  31.     protocol TCP 
  32.  
  33.     real_server 192.168.1.213306{
  34.         weight 3 
  35.         notify_down /opt/mysql/mysql.sh 
  36.             TCP_CHECK { 
  37.             connect_timeout 10 
  38.             nb_get_retry 3 
  39.             delay_before_retry 3 
  40.             connect_port 3306
  41.         } 
  42.     } 
  43. } 
5、测试
  • 在20机器测试，mysql没有启动的情况下，keepalived启动会被自动杀掉，证明keepalived配置正确
service mysql stop 
/usr/local/keepalived/sbin/keepalived -f /usr/local/keepalived/etc/keepalived.conf -D
ps -ef|grep keepalived        看到没有keepalived进程
 
  • 在2边启动mysql并启动keepalived，测试用vip登陆数据库
  1. [root@likun1 keepalived-1.2.13]# mysql -h192.168.1.76-P3306 -uroot -proot
  2. Welcome to the MySQL monitor.  Commands end with ; or \g.
  3. YourMySQL connection id is 682
  4. Server version:5.5.30-log Source distribution
  6. Copyright(c)2000,2013,Oracle and/or its affiliates.All rights reserved.
  8. Oracle is a registered trademark of OracleCorporation and/or its
  9. affiliates.Other names may be trademarks of their respective
  10. owners.
  12. Type'help;' or '\h'for help.Type'\c' to clear the current input statement.
  14. mysql> 
 
21机器查看IP：
  1. [root@likun1 keepalived-1.2.13]# ip addr show
  2. 1: lo:<LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
  3.     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
  4.     inet 127.0.0.1/8 scope host lo
  5.     inet6 ::1/128 scope host 
  6.        valid_lft forever preferred_lft forever
  7. 2: eth0:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
  8.     link/ether 08:00:27:5d:ef:c3 brd ff:ff:ff:ff:ff:ff
  9.     inet 192.168.1.21/24 brd 192.168.1.255 scope global eth0
  10.     inet 192.168.1.76/32 scope global eth0
  11.     inet6 fe80::a00:27ff:fe5d:efc3/64 scope link 
  12.        valid_lft forever preferred_lft forever
 
20机器查看IP：
  1. [root@likun keepalived-1.2.13]# ip addr show
  2. 1: lo:<LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
  3.     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
  4.     inet 127.0.0.1/8 scope host lo
  5.     inet6 ::1/128 scope host 
  6.        valid_lft forever preferred_lft forever
  7. 2: eth0:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
  8.     link/ether 08:00:27:00:58:57 brd ff:ff:ff:ff:ff:ff
  9.     inet 192.168.1.20/24 brd 192.168.1.255 scope global eth0
  10.     inet6 fe80::a00:27ff:fe00:5857/64 scope link 
  11.        valid_lft forever preferred_lft forever
关闭20节点的mysql，发现VIP漂移到21上，并且20上的keepalived被kill
 
  • 杀掉master的keepalived，vip会飘到slave上，slave的日志：
  1. Jul2020:03:31 likun Keepalived_vrrp[8547]: VRRP_Instance(VI_20)Transition to MASTER STATE
  2. Jul2020:03:32 likun Keepalived_vrrp[8547]: VRRP_Instance(VI_20)Entering MASTER STATE
  3. Jul2020:03:32 likun Keepalived_vrrp[8547]: VRRP_Instance(VI_20) setting protocol VIPs.
  4. Jul2020:03:32 likun Keepalived_vrrp[8547]: VRRP_Instance(VI_20)Sending gratuitous ARPs on eth0 for192.168.1.76
  5. Jul2020:03:32 likun Keepalived_healthcheckers[8546]:Netlink reflector reports IP 192.168.1.76 added
  • 再启动master的keepalived，不会抢vip，变为backup state，master的日志：
  1. Jul2020:03:49 likun1 Keepalived[7416]:StartingKeepalived v1.2.13(07/20,2014)
  2. Jul2020:03:49 likun1 Keepalived[7417]:StartingHealthcheck child process, pid=7418
  3. Jul2020:03:49 likun1 Keepalived[7417]:Starting VRRP child process, pid=7419
  4. Jul2020:03:49 likun1 Keepalived_vrrp[7419]:Netlink reflector reports IP 192.168.1.21 added
  5. Jul2020:03:49 likun1 Keepalived_healthcheckers[7418]:Netlink reflector reports IP 192.168.1.21 added
  6. Jul2020:03:49 likun1 Keepalived_healthcheckers[7418]:Netlink reflector reports IP fe80::a00:27ff:fe5d:efc3 added
  7. Jul2020:03:49 likun1 Keepalived_healthcheckers[7418]:RegisteringKernel netlink reflector
  8. Jul2020:03:49 likun1 Keepalived_healthcheckers[7418]:RegisteringKernel netlink command channel
  9. Jul2020:03:49 likun1 Keepalived_vrrp[7419]:Netlink reflector reports IP fe80::a00:27ff:fe5d:efc3 added
  10. Jul2020:03:49 likun1 Keepalived_vrrp[7419]:RegisteringKernel netlink reflector
  11. Jul2020:03:49 likun1 Keepalived_vrrp[7419]:RegisteringKernel netlink command channel
  12. Jul2020:03:49 likun1 Keepalived_vrrp[7419]:Registering gratuitous ARP shared channel
  13. Jul2020:03:49 likun1 Keepalived_vrrp[7419]:Opening file '/usr/local/keepalived/etc/keepalived.conf'.
  14. Jul2020:03:49 likun1 Keepalived_vrrp[7419]:Configuration is using:62953Bytes
  15. Jul2020:03:49 likun1 Keepalived_vrrp[7419]:UsingLinkWatch kernel netlink reflector...
  16. Jul2020:03:49 likun1 Keepalived_vrrp[7419]: VRRP_Instance(VI_21)Entering BACKUP STATE
  17. Jul2020:03:49 likun1 Keepalived_vrrp[7419]: VRRP sockpool:[ifindex(2), proto(112), unicast(0), fd(10,11)]
  18. Jul2020:03:49 likun1 Keepalived_healthcheckers[7418]:Opening file '/usr/local/keepalived/etc/keepalived.conf'.
  19. Jul2020:03:49 likun1 Keepalived_healthcheckers[7418]:Configuration is using:11555Bytes
  20. Jul2020:03:49 likun1 Keepalived_healthcheckers[7418]:UsingLinkWatch kernel netlink reflector...
  21. Jul2020:03:49 likun1 Keepalived_healthcheckers[7418]:Activating healthchecker for service [192.168.1.21]:3306
 
 
切换时不会kill keepalived的方式
20、21先配置主主架构
2边数据库做授权：
root@localhost 19:30:38 [db3]> GRANT REPLICATION CLIENT ON *.* TO 'monitor'@'%' IDENTIFIED BY 'm0n1tor'; 
Query OK, 0 rows affected (0.00 sec)
flush privileges
 
2边系统拷贝检测脚本并+x
chmod +x /usr/local/keepalived/checkMySQL.py        (脚本在附件，要检查一下脚本变量值)
 
两边配置文件做成如下：
20：
  1. [root@likun ~]# cat /usr/local/keepalived/etc/keepalived.conf 
  2. vrrp_script vs_mysql_20 {
  3.     script "/usr/local/keepalived/checkMySQL.py -h 192.168.1.20 -P 3306"
  4.     interval 60 
  5. }
  6. vrrp_instance VI_20 {
  7.     state BACKUP
  8.     nopreempt
  9.     interface eth0
  10.     virtual_router_id 21
  11.     priority 100
  12.     advert_int 5
  13.     authentication {
  14.         auth_type PASS
  15.         auth_pass 1111
  16.     }
  17.     track_script {
  18.        vs_mysql_20
  19.     }
  20.     virtual_ipaddress {
  21.         192.168.1.76
  22.     }
  23. } 
21：
  1. [root@likun1 ~]# cat /usr/local/keepalived/etc/keepalived.conf 
  2. vrrp_script vs_mysql_21 {
  3.     script "/usr/local/keepalived/checkMySQL.py -h 192.168.1.21 -P 3306"
  4.     interval 60 
  5. }
  6. vrrp_instance VI_21 {
  7.     state BACKUP
  8.     nopreempt
  9.     interface eth0
  10.     virtual_router_id 21
  11.     priority 90
  12.     advert_int 5
  13.     authentication {
  14.         auth_type PASS
  15.         auth_pass 1111
  16.     }
  17.     track_script {
  18.        vs_mysql_21
  19.     }
  20.     virtual_ipaddress {
  21.         192.168.1.76
  22.     }
  23. } 
启动20的keepalived，并查看日志，发现启动为master状态，vip绑定：
  1. [root@likun ~]#/usr/local/keepalived/sbin/keepalived -f /usr/local/keepalived/etc/keepalived.conf -D
  2. [root@likun ~]# tail -f /var/log/messages
  3. Aug  820:58:41 likun Keepalived[8023]:StoppingKeepalived v1.2.13(07/20,2014)
  4. Aug  820:59:04 likun Keepalived[8064]:StartingKeepalived v1.2.13(07/20,2014)
  5. Aug  820:59:04 likun Keepalived[8065]:StartingHealthcheck child process, pid=8066
  6. Aug  820:59:04 likun Keepalived[8065]:Starting VRRP child process, pid=8067
  7. Aug  820:59:04 likun Keepalived_vrrp[8067]:Netlink reflector reports IP 192.168.1.20 added
  8. Aug  820:59:04 likun Keepalived_vrrp[8067]:Netlink reflector reports IP 10.0.3.15 added
  9. Aug  820:59:04 likun Keepalived_vrrp[8067]:Netlink reflector reports IP fe80::a00:27ff:fe00:5857 added
  10. Aug  820:59:04 likun Keepalived_healthcheckers[8066]:Netlink reflector reports IP 192.168.1.20 added
  11. Aug  820:59:04 likun Keepalived_vrrp[8067]:Netlink reflector reports IP fe80::a00:27ff:fe5d:683a added
  12. Aug  820:59:04 likun Keepalived_vrrp[8067]:RegisteringKernel netlink reflector
  13. Aug  820:59:04 likun Keepalived_vrrp[8067]:RegisteringKernel netlink command channel
  14. Aug  820:59:04 likun Keepalived_vrrp[8067]:Registering gratuitous ARP shared channel
  15. Aug  820:59:04 likun Keepalived_healthcheckers[8066]:Netlink reflector reports IP 10.0.3.15 added
  16. Aug  820:59:04 likun Keepalived_healthcheckers[8066]:Netlink reflector reports IP fe80::a00:27ff:fe00:5857 added
  17. Aug  820:59:04 likun Keepalived_healthcheckers[8066]:Netlink reflector reports IP fe80::a00:27ff:fe5d:683a added
  18. Aug  820:59:04 likun Keepalived_healthcheckers[8066]:RegisteringKernel netlink reflector
  19. Aug  820:59:04 likun Keepalived_healthcheckers[8066]:RegisteringKernel netlink command channel
  20. Aug  820:59:05 likun Keepalived_vrrp[8067]:Opening file '/usr/local/keepalived/etc/keepalived.conf'.
  21. Aug  820:59:05 likun Keepalived_healthcheckers[8066]:Opening file '/usr/local/keepalived/etc/keepalived.conf'.
  22. Aug  820:59:05 likun Keepalived_vrrp[8067]:Configuration is using:62993Bytes
  23. Aug  820:59:05 likun Keepalived_healthcheckers[8066]:Configuration is using:5287Bytes
  24. Aug  820:59:05 likun Keepalived_vrrp[8067]:UsingLinkWatch kernel netlink reflector...
  25. Aug  820:59:05 likun Keepalived_vrrp[8067]: VRRP_Instance(VI_20)Entering BACKUP STATE
  26. Aug  820:59:05 likun Keepalived_vrrp[8067]: VRRP sockpool:[ifindex(2), proto(112), unicast(0), fd(10,11)]
  27. Aug  820:59:05 likun Keepalived_healthcheckers[8066]:UsingLinkWatch kernel netlink reflector...
  28. Aug  820:59:07 likun Keepalived_vrrp[8067]: VRRP_Script(vs_mysql_20) succeeded
  29. Aug  820:59:20 likun Keepalived_vrrp[8067]: VRRP_Instance(VI_20)Transition to MASTER STATE
  30. Aug  820:59:25 likun Keepalived_vrrp[8067]: VRRP_Instance(VI_20)Entering MASTER STATE
  31. Aug  820:59:25 likun Keepalived_vrrp[8067]: VRRP_Instance(VI_20) setting protocol VIPs.
  32. Aug  820:59:25 likun Keepalived_vrrp[8067]: VRRP_Instance(VI_20)Sending gratuitous ARPs on eth0 for192.168.1.76
  33. Aug  820:59:25 likun Keepalived_healthcheckers[8066]:Netlink reflector reports IP 192.168.1.76 added
  34. Aug  820:59:30 likun Keepalived_vrrp[8067]: VRRP_Instance(VI_20)Sending gratuitous ARPs on eth0 for192.168.1.76
启动21的keepalived，并查看日志，启动为backup状态：
  1. [root@likun1 ~]#/usr/local/keepalived/sbin/keepalived -f /usr/local/keepalived/etc/keepalived.conf -D
  2. [root@likun1 ~]# tail -f /var/log/messages
  3. Aug  918:11:27 likun1 Keepalived[3355]:StartingKeepalived v1.2.13(07/20,2014)
  4. Aug  918:11:27 likun1 Keepalived[3356]:StartingHealthcheck child process, pid=3357
  5. Aug  918:11:27 likun1 Keepalived[3356]:Starting VRRP child process, pid=3358
  6. Aug  918:11:27 likun1 Keepalived_vrrp[3358]:Netlink reflector reports IP 192.168.1.21 added
  7. Aug  918:11:27 likun1 Keepalived_healthcheckers[3357]:Netlink reflector reports IP 192.168.1.21 added
  8. Aug  918:11:27 likun1 Keepalived_healthcheckers[3357]:Netlink reflector reports IP 10.0.3.15 added
  9. Aug  918:11:27 likun1 Keepalived_healthcheckers[3357]:Netlink reflector reports IP fe80::a00:27ff:fe5d:efc3 added
  10. Aug  918:11:27 likun1 Keepalived_vrrp[3358]:Netlink reflector reports IP 10.0.3.15 added
  11. Aug  918:11:27 likun1 Keepalived_healthcheckers[3357]:Netlink reflector reports IP fe80::a00:27ff:fe97:754a added
  12. Aug  918:11:27 likun1 Keepalived_healthcheckers[3357]:RegisteringKernel netlink reflector
  13. Aug  918:11:27 likun1 Keepalived_healthcheckers[3357]:RegisteringKernel netlink command channel
  14. Aug  918:11:27 likun1 Keepalived_vrrp[3358]:Netlink reflector reports IP fe80::a00:27ff:fe5d:efc3 added
  15. Aug  918:11:27 likun1 Keepalived_vrrp[3358]:Netlink reflector reports IP fe80::a00:27ff:fe97:754a added
  16. Aug  918:11:27 likun1 Keepalived_vrrp[3358]:RegisteringKernel netlink reflector
  17. Aug  918:11:27 likun1 Keepalived_vrrp[3358]:RegisteringKernel netlink command channel
  18. Aug  918:11:27 likun1 Keepalived_vrrp[3358]:Registering gratuitous ARP shared channel
  19. Aug  918:11:30 likun1 Keepalived_vrrp[3358]:Opening file '/usr/local/keepalived/etc/keepalived.conf'.
  20. Aug  918:11:30 likun1 Keepalived_healthcheckers[3357]:Opening file '/usr/local/keepalived/etc/keepalived.conf'.
  21. Aug  918:11:30 likun1 Keepalived_vrrp[3358]:Configuration is using:63001Bytes
  22. Aug  918:11:30 likun1 Keepalived_healthcheckers[3357]:Configuration is using:5295Bytes
  23. Aug  918:11:30 likun1 Keepalived_vrrp[3358]:UsingLinkWatch kernel netlink reflector...
  24. Aug  918:11:30 likun1 Keepalived_vrrp[3358]: VRRP_Instance(VI_21)Entering BACKUP STATE
  25. Aug  918:11:30 likun1 Keepalived_vrrp[3358]: VRRP sockpool:[ifindex(2), proto(112), unicast(0), fd(10,11)]
  26. Aug  918:11:30 likun1 Keepalived_healthcheckers[3357]:UsingLinkWatch kernel netlink reflector...
  27. Aug  918:11:31 likun1 Keepalived_vrrp[3358]: VRRP_Script(vs_mysql_21) succeeded
20机器关闭mysql，看到20 keepalived切换为fault状态，21机器切换为master状态并绑定vip
  1. 20日志：
  2. Aug  823:09:05 likun Keepalived_vrrp[8067]: VRRP_Script(vs_mysql_20) failed
  3. Aug  823:09:08 likun Keepalived_vrrp[8067]: VRRP_Instance(VI_20)Entering FAULT STATE
  4. Aug  823:09:08 likun Keepalived_vrrp[8067]: VRRP_Instance(VI_20) removing protocol VIPs.
  5. Aug  823:09:08 likun Keepalived_vrrp[8067]: VRRP_Instance(VI_20)Now in FAULT state
  6. Aug  823:09:08 likun Keepalived_healthcheckers[8066]:Netlink reflector reports IP 192.168.1.76 removed
  1. 21日志：
  2. Aug  920:21:00 likun1 Keepalived_vrrp[3358]: VRRP_Instance(VI_21)Transition to MASTER STATE
  3. Aug  920:21:05 likun1 Keepalived_vrrp[3358]: VRRP_Instance(VI_21)Entering MASTER STATE
  4. Aug  920:21:05 likun1 Keepalived_vrrp[3358]: VRRP_Instance(VI_21) setting protocol VIPs.
  5. Aug  920:21:05 likun1 Keepalived_healthcheckers[3357]:Netlink reflector reports IP 192.168.1.76 added
  6. Aug  920:21:05 likun1 avahi-daemon[1320]:Registeringnew address record for192.168.1.76 on eth0.IPv4.
  7. Aug  920:21:05 likun1 Keepalived_vrrp[3358]: VRRP_Instance(VI_21)Sending gratuitous ARPs on eth0 for192.168.1.76
  8. Aug  920:21:10 likun1 Keepalived_vrrp[3358]: VRRP_Instance(VI_21)Sending gratuitous ARPs on eth0 for192.168.1.76
20机器再次启动mysql，keepalived会切换为backup状态，但不会抢vip
  1. Aug  823:49:05 likun Keepalived_vrrp[8067]: VRRP_Script(vs_mysql_20) succeeded
  2. Aug  823:49:08 likun Keepalived_vrrp[8067]: VRRP_Instance(VI_20)Entering BACKUP STATE
 
 
 
keepalived双主带一从的配置方式
20 <-->21（双主）
 |
22(从库)
 
 

14、高可用keepalived搭建及切换的更多相关文章

  1. 高可用Keepalived+LVS搭建流程

    本流程搭建1个master,1个backup节点的Keepalived,使用lvs轮询2个节点的服务. 一.使用版本 CentOS 7.7 Keepalived 1.3.5 ipvsadm 1.27( ...

  2. 美团点评基于MGR的CMDB高可用架构搭建之路【转】

    王志朋 美团点评DBA 曾在京东金融担任DBA,目前就职于美团点评,主要负责金融业务线数据库及基础组件数据库的运维. MySQL Group Replication(以下简称MGR),于5.7.17版 ...

  3. 解决nginx负载均衡高可用keepalived只针对物理机的问题

    在高可用keepalived软件,在默认的情况下仅仅在对方机器宕机或keepalived停掉的时候才会接管业务. 但是在实际工作过程中,例如在nginx负载均衡工作实例中,nginx服务已停止,而ke ...

  4. haproxy + rabbitmq + keepalived的高可用环境搭建

    一.rabbitmq的搭建:参考rabbimq的安装及集群设置 二.安装和配置haproxy 1.安装haproxyyum install haproxy 2.安装rsysloga. 检查rsyslo ...

  5. Redis + keepalived 高可用群集搭建

    本次实验环境介绍: 操作系统: Centos 7.3 IP : 192.168.10.10 Centos 7.3 IP : 192.168.10.20  VIP    地址   : 192.168.1 ...

  6. mamcached+（magent+keepalived高可用）搭建及理论概述

    目录 一.理论概述 工作流程 二.部署 环境 环境概述 部署 三.测试 四.总结 一.理论概述 Memcached服务器端与PHP-Memcache客户端安装配置_服务器应用_Linux公社-Linu ...

  7. nginx1.14.0版本高可用——keepalived双机热备

    nginx不支持主从,所以我们需要使用keepalive支持高可用. keepalived重要知识点 在局域网内,每个主机上各安装一个keepalived,注意关闭防火墙firewalld,然后设定一 ...

  8. HA高可用的搭建

    HA 即 (high available)高可用,又被叫做双机热备,用于关键性业务. 简单理解就是,有两台机器A和B,正常是A提供服务,B待命闲置,当A宕机或服务宕掉,会切换至B机器继续提供服务.常用 ...

  9. linux下mysql5.7的MHA高可用架构搭建

    一.MHA简介 MHA(Master High Availability)目前在mysql高可用方面比较成熟.是一套优秀的作为 mysql高可用性环境下故障切换和主从提升的高可用软件.在MySQL故障 ...

随机推荐

  1. 将setter方法与itemClick: 进行类比

        https://www.evernote.com/shard/s227/sh/a0c3afa3-8792-4756-8594-d2387a7f57ad/b561ff665af9ad401c8e ...

  2. BZoj 1003 物流运输 DP+最短路

    2013-09-11 09:56 W[I]代表前I天能取得的最小花费,假设在第J天更改一次路线,那么如果有 W[I]>W[J]+第j+1到第I天的最小花费+更改路线的花费(K) 那么更新W[I] ...

  3. Pycharm中快捷键大全

    #1.按住ctrl然后鼠标放在函数上就会提示出这个函数有那些参数,双击进入该函数. 1.Pycharm中快捷键大全,遇到一个更新一个 撤销与反撤销:Ctrl + z,Ctrl + Shift + z ...

  4. Linux2.6.32内核笔记（5）在应用程序中移植使用内核链表【转】

    转自:http://blog.csdn.net/Deep_l_zh/article/details/48392935 版权声明:本文为博主原创文章,未经博主允许不得转载. 摘要:将内核链表移植到应用程 ...

  5. 3.资源调度框架yarn

    既然要分析yarn,无非是从以下方面分析 (一).yarn产生背景(二).yarn概述(三).yarn架构(四).yarn执行流程(五).yarn环境搭建(六).提交作业到yarn上运行 (一).ya ...

  6. Python实现图片转字符画

    from PIL import Image def get_char(r, g, b, alpha=256): ascii_char = '''$@B%8&WM#*oahkbdpqwmZO0Q ...

  7. could not find or load the Qt platform plugin "xcb"

    没有解决 一些资料: https://wiki.qt.io/Install_Qt_5_on_Ubuntu http://doc.qt.io/qt-5/linux-requirements.html h ...

  8. css项目列表如何水平放置

    列表项目默认分行排列,那么将列表项设置浮动就可以实现水平放置 1 li{float:left;} 示例如下: 创建Html元素 1 2 3 4 5 6 <ul>     <li> ...

  9. [BZOJ4199][Noi2015]品酒大会 树形DP+后缀自动机

    由于要找后缀的前缀,所以先用反串建立SAM. link边组成了后缀树. 两个子串的最长公共前缀是LCA的step 树形dp即可. #include<iostream> #include&l ...

  10. [libgdx游戏开发教程]使用Libgdx进行游戏开发(8)-粒子系统

    没有美工的程序员,能够依赖的还有粒子系统. 这一章我们将使用libGDX的粒子系统线性插值以及其他的方法来增加一些特效. 你也可以使用自己编辑的粒子效果,比如这个粒子文件dust:http://fil ...