笔记九

#################dns集群############

1.dns集群的基础配置

需求:一台dns服务器不能满足大量的访问需求,需要增加辅助dns服务器

辅助dns端 (client) :

vim /etc/resolv.conf 修改内容为:

3 nameserver 172.25.254.207

vim /etc/named.conf 修改为:

11         listen-on port 53 { any; };

17         allow-query     { any; };

31         dnssec-validation no;

vim /etc/named.rfc1912.zones

25 zone "westos.com" IN {

26         type slave;

27         file "slaves/westos.com.zone";

28         allow-update { none; };

29         masters { 172.25.254.107; };

30 };

ll /var/named --> 查看slaves目录信息

主dns端 (dns) :

vim /etc/named.conf 修改为:

11         listen-on port 53 { any; };

17         allow-query     { any; };

31         dnssec-validation no;

vim /etc/named.rfc1912.zones 修改内容为:

25 zone "westos.com" IN {

26         type master;

27         file "westos.com.zone";

28         allow-update { none; };

29    allow-transfer { 172.25.254.207; }; ##允许谁同步

30 };

systemctl restart named

测试 (desktop端):

systemctl restart named

dig www.westos.com

@@实例:

<1> client端操作不变

<2> dns端操作:

vim /etc/named.conf 修改为:

11         listen-on port 53 { any; };

17         allow-query     { any; };

31         dnssec-validation no;

vim /etc/named.rfc1912.zones 修改内容为:

25 zone "westos.com" IN {

26         type master;

27         file "westos.com.zone";

28         allow-update { key lzt; };

29         allow-transfer { 172.25.254.207; };

30 };

systemctl restart named

<3> 测试:

[[email protected] slaves]# systemctl restart named

[[email protected] slaves]# dig www.westos.com

;www.westos.com. IN A

;; ANSWER SECTION:

www.westos.com. 86400 IN A 172.25.0.108

;; AUTHORITY SECTION:

westos.com. 86400 IN NS dns.westos.com.

;; ADDITIONAL SECTION:

dns.westos.com. 86400 IN A 172.25.0.107

;; Query time: 1 msec

;; SERVER: 172.25.254.207#53(172.25.254.207)

2.自动同步dns服务

client端不做改变

dns端:

vim /etc/named.rfc1912.zones 修改内容为:

25 zone "westos.com" IN {

26         type master;

27         file "westos.com.zone";

28         allow-update { none; };

29         allow-transfer { 172.25.254.207; };

30         also-notify { 172.25.254.207; }; ##当dns文件被改变后,向谁推送新的数据

31 };

vim /var/named/westos.com.zone 修改内容为:

2 @       IN SOA  dns.westos.com. root.westos.com. (

3                  2016112601    ; serial

9 dns             A       172.25.0.107

10 www             A       172.25.0.112

systemctl restart named

dns同步时,本质是比较 serial 前的标识 (2016112601) 的不同,每一次对 /var/named/westos.com.zone 内容做修改时都应该改变标识符。

测试:

在client主机测试:

dig www.westos.com

实例:

[[email protected] slaves]# dig www.westos.com

;www.westos.com. IN A

;; ANSWER SECTION:

www.westos.com. 86400 IN A 172.25.0.112

;; AUTHORITY SECTION:

westos.com. 86400 IN NS dns.westos.com.

;; ADDITIONAL SECTION:

dns.westos.com. 86400 IN A 172.25.0.107

;; Query time: 0 msec

;; SERVER: 172.25.254.207#53(172.25.254.207)

3.远程修改dns服务

dns端:

vim /etc/named.rfc1912.zones 修改内容为:

zone "westos.com" IN {

type master;

file "westos.com.zone";

allow-update { 172.25.254.207; }; ##允许谁去更新

allow-transfer { 172.25.254.207; };

also-notify { 172.25.254.207; };

};

chmod 770 /var/named

cp -p /var/named/westos.com.zone  /mnt/westos.com.zone

client端:

nsupdate

> server 172.25.254.107

> update delete www.westos.com

> send

update failed: SERVFAIL ##报错原因:在 主dns 端漏做 chmod 770 /var/named

> server 172.25.254.107

> update delete www.westos.com ##删除www.westos.com

> send ##发送

> server 172.25.254.107

> update add www.westos.com 86400 A 172.25.254.1 ##添加 www.westos.com 对应的ip为 172.25.254.1,此处的 86400 代表的是dns一般保存周期为一天,即,86400 秒

> send

> quit

恢复:rm -fr /var/named/westos.com.zone /var/named/westos.com.zone.jnl

cp -p /mnt/westos.com.zone /var/named/westos.com.zone

实例:

client 端:

[[email protected] ~]# dig www.westos.com ##此处是删除了 www.westos.com 的效果

; <<>> DiG 9.9.4-RedHat-9.9.4-14.el7 <<>> www.westos.com

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 38482

;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

; AUTHORITY SECTION:

westos.com. 10800 IN SOA dns.westos.com.westos.com. root.westos.com. 2016112907 86400 3600 604800 10800

;; Query time: 1 msec

;; SERVER: 172.25.254.207#53(172.25.254.207)

;; WHEN: Wed Nov 30 01:07:30 EST 2016

;; MSG SIZE  rcvd: 99

[[email protected] ~]# dig dns.westos.com

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6513

;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 4096

;; QUESTION SECTION:

;dns.westos.com. IN A

;; ANSWER SECTION:

dns.westos.com. 86400 IN A 172.25.254.107

;; AUTHORITY SECTION:

westos.com. 86400 IN NS dns.westos.com.

;; WHEN: Wed Nov 30 01:07:39 EST 2016

;; MSG SIZE  rcvd: 73

[[email protected] ~]# dig www.westos.com ##此处是添加 www.westos.com 对应的ip为 172.25.254.1 的情况

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 20619

;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 2

;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 4096

;; QUESTION SECTION:

;www.westos.com. IN A

;; ANSWER SECTION:

www.westos.com. 86400 IN A 172.25.254.1

;; AUTHORITY SECTION:

westos.com. 86400 IN NS dns.westos.com.

;; ADDITIONAL SECTION:

dns.westos.com. 86400 IN A 172.25.254.207

;; WHEN: Wed Nov 30 01:09:53 EST 2016

;; MSG SIZE  rcvd: 93

4.设置密钥远程修改dns服务

dns端:

cp -p /etc/rndc.key /etc/westos.key ##将系统密码文件连同权限复制一份为自己名称的密码文件

cd /mnt/

dnssec-keygen -a HMAC-MD5 -b 128 -n HOST westos

cat /mnt/Kwestos.+157+08237.private

cat /mnt/Kwestos.+157+08237.key ##可以发现两个文件中密文相同

vim /etc/westos.key

将原始文件内容(如下)修改:

key "rndc-key" {

algorithm hmac-md5;

secret "KgE1w+fRiEQRov1RhPqUDg==";

};

|

| ##修改成下面的内容

\|/

key "westos" { ##第一处修改点:名字修改为westos

algorithm hmac-md5;

secret "0QsS0gNcgoJPBCerborLmQ=="; ##第二处修改点:密文修改为 /mnt/Kwestos.+157+08237.key或者/mnt/Kwestos.+157+08237.private 文件中的密文,然后保存退出

};

vim /etc/named.conf

修改内容为:

42 };

43 include "/etc/westos.key"; ##修改点-->将密码所在的文件包含进去

44 logging {

scp Kwestos.+157+08237.* [email protected]:/mnt/ ##将密钥发送给client端

systemctl restart named

client端:

cd /mnt/

nsupdate -k Kwestos.+157+08237.private

或者

nsupdate -k /mnt/Kwestos.+157+08237.private

> server 172.25.254.207

> update add www.westos.com 86400 A 172.25.254.22 ##再次添加一个www.westos.com所对应的ip为 172.25.254.22

> send

> quit

恢复:rm -fr /var/named/westos.com.zone /var/named/westos.com.zone.jnl

cp -p /mnt/westos.com.zone /var/named/westos.com.zone

实例:

[[email protected] ~]# dig www.westos.com

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 63371

;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 1, ADDITIONAL: 2

;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 4096

;; QUESTION SECTION:

;www.westos.com. IN A

;; ANSWER SECTION:

www.westos.com. 86400 IN A 172.25.254.22

www.westos.com. 86400 IN A 172.25.254.220

;; AUTHORITY SECTION:

westos.com. 86400 IN NS dns.westos.com.

;; ADDITIONAL SECTION:

dns.westos.com. 86400 IN A 172.25.254.207

;; WHEN: Wed Nov 30 02:15:42 EST 2016

;; MSG SIZE  rcvd: 109

5.使用dhcp服务自动配置dns服务(ddns 或 花生壳)

DHCP + DNS = DDNS

dns端:

安装dhcp服务

yum install dhcp -y

systemctl start dhcpd

systemctl start firewalld 或者 将dhcp服务添加到防火墙允许的服务中去

将selinux设置为警告模式

cp /usr/share/doc/dhcp-4.2.5/dhcp.conf.example /etc/dhcp/dhcpd.conf

vim /etc/dhcp/dhcpd.conf

修改内容为:

7 option domain-name "westos.com";

8 option domain-name-servers 172.25.254.107;

14 ddns-update-style interim;

删除 27,28 行

30 subnet 172.25.254.0 netmask 255.255.255.0 {

31   range 172.25.254.207 172.25.254.210;

32   option routers 172.25.254.107;

33 }

34

35 key westos {

36         algorithm hmac-md5;

37         secret 0QsS0gNcgoJPBCerborLmQ==;

38 };

39

40 zone westos.com. {

41         primary 127.0.0.1;

42         key westos;

43 }

systemctl restart dhcpd

systemctl restart named

client端:

设置主机名为 music.westos.com

systemctl start firewalld 或者 将dhcp服务添加到防火墙允许的服务中去

将selinux设置为警告模式

将/etc/resolv.conf内容修改为

namedserver 172.25.254.107

配置/etc/sysconfig/network-scripts/ifcfg-eth0 文件:

vim /etc/sysconfig/network-scripts/ifcfg-eth0 内容修改为:

2 BOOTPROTO=dhcp

systemctl restart network

dig music.westos.com

测试:

[[email protected] ~]# dig music.westos.com

; <<>> DiG 9.9.4-RedHat-9.9.4-14.el7 <<>> music.westos.com

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 53938

;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 2

;; OPT PSEUDOSECTION:

; EDNS: version: 0, flags:; udp: 4096

;; QUESTION SECTION:

;music.westos.com. IN A

;; ANSWER SECTION:

music.westos.com. 300 IN A 172.25.254.207

;; AUTHORITY SECTION:

westos.com. 86400 IN NS dns.westos.com.

;; ADDITIONAL SECTION:

dns.westos.com. 86400 IN A 172.25.254.107

;; Query time: 1 msec

;; SERVER: 172.25.254.107#53(172.25.254.107)

;; WHEN: Wed Nov 30 19:57:24 EST 2016

;; MSG SIZE  rcvd: 95

#########数据库###########

1.安装与基本操作

yum install mysql mysql-server

mysqladmin -uroot -predhat password westos 修改本地mysql root密码

mysqladmin -uroot -predhat -h 172.25.254.207 password westos 修改远程192.168.0.188 mysql服务器 root密码

mysql_secure_installation 第一次安装mysql以后通过这条命令可以对mysql进行设置

mysql -uroot -predhat 从本机登录mysql数据库

show databases; 显示数据库

use mysql; 进入数据库

show tables; 显示数据库中的表

desc user; 查看user表的数据结构

flush privileges; 刷新数据库信息

select host,user,password from user; 查询user表中的host,user,password字段

create database westos; 创建westos数据库

use westos;

create table linux (username varchar(15) not null,password varchar(15) not null); 创建表linux,username,password字段

select * from mysql.user; 查询mysql库下的user表中的所有

alter table linux add age varchar(4); 添加age字段到linux表中

ALTER TABLE linux DROP age 删除age字段

ALTER TABLE linux ADD age  VARCHAR(5)  AFTER name 在name字段后添加字段age

show tables;

desc linux;

实例:

[[email protected] mnt]# yum install mariadb-server.x86_64 -y

Complete!

[[email protected] mnt]# systemctl start mariadb

[[email protected] mnt]# systemctl stop firewalld

[[email protected] mnt]# vim /etc/my.cnf

[[email protected] mnt]# mysql

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 2

MariaDB [(none)]> quit

Bye

[[email protected] mnt]# mysql_secure_installation

/usr/bin/mysql_secure_installation: line 379: find_mysql_client: command not found

Set root password? [Y/n]

New password: ##输入密码

Re-enter new password: ##确认密码

Password updated successfully!

Reloading privilege tables..

... Success!

Remove anonymous users? [Y/n] ##回车

... Success!

Disallow root login remotely? [Y/n] ##回车

... Success!

Remove test database and access to it? [Y/n]   ##回车

- Dropping test database...

... Success!

- Removing privileges on test database...

... Success!

Reload privilege tables now? [Y/n]   ##回车

... Success!

[[email protected] mnt]# systemctl restart mariadb.service

[[email protected] mnt]# mysql -uroot -predhat

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 2

MariaDB [(none)]> quit

Bye

[[email protected] mnt]# mysql -uroot -p

Enter password:

Welcome to the MariaDB monitor.  Commands end with ; or \g.

MariaDB [(none)]> quit

Bye

[[email protected] mnt]# mysql -uroot -predhat ##登录

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 4

Server version: 5.5.35-MariaDB MariaDB Server

Copyright (c) 2000, 2013, Oracle, Monty Program Ab and others.

Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.

MariaDB [(none)]> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

+--------------------+

3 rows in set (0.01 sec)

MariaDB [(none)]> use mysql;

Reading table information for completion of table and column names

You can turn off this feature to get a quicker startup with -A

Database changed

MariaDB [mysql]> SHOW TABLES;

+---------------------------+

| Tables_in_mysql           |

+---------------------------+

| columns_priv              |

| db                        |

| event                     |

| func                      |

| general_log               |

| help_category             |

| help_keyword              |

| help_relation             |

| help_topic                |

| host                      |

| ndb_binlog_index          |

| plugin                    |

| proc                      |

| procs_priv                |

| proxies_priv              |

| servers                   |

| slow_log                  |

| tables_priv               |

| time_zone                 |

| time_zone_leap_second     |

| time_zone_name            |

| time_zone_transition      |

| time_zone_transition_type |

| user                      |

+---------------------------+

24 rows in set (0.00 sec)

MariaDB [mysql]> DESC USER;

ERROR 1146 (42S02): Table ‘mysql.USER‘ doesn‘t exist

MariaDB [mysql]> DESC user;

+------------------------+-----------------------------------+------+-----+---------+-------+

| Field                  | Type                              | Null | Key | Default | Extra |

+------------------------+-----------------------------------+------+-----+---------+-------+

| Host                   | char(60)                          | NO   | PRI |         |       |

| User                   | char(16)                          | NO   | PRI |         |       |

| Password               | char(41)                          | NO   |     |         |       |

| Select_priv            | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Insert_priv            | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Update_priv            | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Delete_priv            | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Create_priv            | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Drop_priv              | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Reload_priv            | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Shutdown_priv          | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Process_priv           | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| File_priv              | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Grant_priv             | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| References_priv        | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Index_priv             | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Alter_priv             | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Show_db_priv           | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Super_priv             | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Create_tmp_table_priv  | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Lock_tables_priv       | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Execute_priv           | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Repl_slave_priv        | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Repl_client_priv       | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Create_view_priv       | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Show_view_priv         | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Create_routine_priv    | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Alter_routine_priv     | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Create_user_priv       | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Event_priv             | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Trigger_priv           | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| Create_tablespace_priv | enum(‘N‘,‘Y‘)                     | NO   |     | N       |       |

| ssl_type               | enum(‘‘,‘ANY‘,‘X509‘,‘SPECIFIED‘) | NO   |     |         |       |

| ssl_cipher             | blob                              | NO   |     | NULL    |       |

| x509_issuer            | blob                              | NO   |     | NULL    |       |

| x509_subject           | blob                              | NO   |     | NULL    |       |

| max_questions          | int(11) unsigned                  | NO   |     | 0       |       |

| max_updates            | int(11) unsigned                  | NO   |     | 0       |       |

| max_connections        | int(11) unsigned                  | NO   |     | 0       |       |

| max_user_connections   | int(11)                           | NO   |     | 0       |       |

| plugin                 | char(64)                          | NO   |     |         |       |

| authentication_string  | text                              | NO   |     | NULL    |       |

+------------------------+-----------------------------------+------+-----+---------+-------+

42 rows in set (0.00 sec)

MariaDB [mysql]> SELECT Host,User,Password from user;

+-----------+------+-------------------------------------------+

| Host      | User | Password                                  |

+-----------+------+-------------------------------------------+

| localhost | root | *84BB5DF4823DA319BBF86C99624479A198E6EEE9 |

| 127.0.0.1 | root | *84BB5DF4823DA319BBF86C99624479A198E6EEE9 |

| ::1       | root | *84BB5DF4823DA319BBF86C99624479A198E6EEE9 |

+-----------+------+-------------------------------------------+

3 rows in set (0.00 sec)

MariaDB [mysql]> quit

Bye

[[email protected] mnt]# mysql -uroot -predhat

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 5

Server version: 5.5.35-MariaDB MariaDB Server

Copyright (c) 2000, 2013, Oracle, Monty Program Ab and others.

Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.

MariaDB [(none)]> CREATE DATABASE westos;

Query OK, 1 row affected (0.00 sec)

MariaDB [(none)]> use westos;

Database changed

MariaDB [westos]> CREATE TABLE Utab (username varchar(16) not null, passwd varchar(8) not null,age varchar(4));

Query OK, 0 rows affected (0.40 sec)

MariaDB [westos]> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

| westos             |

+--------------------+

4 rows in set (0.00 sec)

MariaDB [westos]> show tables;

+------------------+

| Tables_in_westos |

+------------------+

| Utab             |

+------------------+

1 row in set (0.01 sec)

MariaDB [westos]> desc Utab;

+----------+-------------+------+-----+---------+-------+

| Field    | Type        | Null | Key | Default | Extra |

+----------+-------------+------+-----+---------+-------+

| username | varchar(16) | NO   |     | NULL    |       |

| passwd   | varchar(8)  | NO   |     | NULL    |       |

| age      | varchar(4)  | YES  |     | NULL    |       |

+----------+-------------+------+-----+---------+-------+

3 rows in set (0.00 sec)

MariaDB [westos]> select * from Utab;

Empty set (0.00 sec)

MariaDB [westos]> insert into Utab values (‘小正太‘,‘redhat‘,‘18‘);

Query OK, 1 row affected, 1 warning (0.30 sec)

MariaDB [westos]> insert into Utab values(‘lzt‘,‘redhat‘,‘20‘);

Query OK, 1 row affected (0.07 sec)

MariaDB [westos]> select * from Utab;

+----------+--------+------+

| username | passwd | age  |

+----------+--------+------+

| ???      | redhat | 18   |

| lzt      | redhat | 20   |

+----------+--------+------+

2 rows in set (0.00 sec)

MariaDB [westos]> ALTER TABLE Utab ADD class varchar(10) AFTER password;

ERROR 1054 (42S22): Unknown column ‘password‘ in ‘Utab‘

MariaDB [westos]> ALTER TABLE Utab ADD class varchar(10) AFTER passwd;

Query OK, 2 rows affected (0.10 sec)

Records: 2  Duplicates: 0  Warnings: 0

MariaDB [westos]> SELECT * FROM Utab;

+----------+--------+-------+------+

| username | passwd | class | age  |

+----------+--------+-------+------+

| ???      | redhat | NULL  | 18   |

| lzt      | redhat | NULL  | 20   |

+----------+--------+-------+------+

2 rows in set (0.00 sec)

MariaDB [westos]> UPDATE Utab SET class=‘1‘ WHERE username=‘lzt‘;

Query OK, 1 row affected (0.34 sec)

Rows matched: 1  Changed: 1  Warnings: 0

MariaDB [westos]> select * from Utab;

+----------+--------+-------+------+

| username | passwd | class | age  |

+----------+--------+-------+------+

| ???      | redhat | NULL  | 18   |

| lzt      | redhat | 1     | 20   |

+----------+--------+-------+------+

2 rows in set (0.00 sec)

MariaDB [westos]> UPDATE Utab SET class=‘1‘;

Query OK, 1 row affected (0.29 sec)

Rows matched: 2  Changed: 1  Warnings: 0

MariaDB [westos]> select * from Utab;

+----------+--------+-------+------+

| username | passwd | class | age  |

+----------+--------+-------+------+

| ???      | redhat | 1     | 18   |

| lzt      | redhat | 1     | 20   |

+----------+--------+-------+------+

2 rows in set (0.00 sec)

MariaDB [westos]> delete from Utab where username=‘lzt‘;

Query OK, 1 row affected (0.30 sec)

MariaDB [westos]> select * from Utab;

+----------+--------+-------+------+

| username | passwd | class | age  |

+----------+--------+-------+------+

| ???      | redhat | 1     | 18   |

+----------+--------+-------+------+

1 row in set (0.00 sec)

MariaDB [westos]> drop table Utab;

Query OK, 0 rows affected (0.04 sec)

MariaDB [westos]> select * from Utab;

ERROR 1146 (42S02): Table ‘westos.Utab‘ doesn‘t exist

MariaDB [westos]> drop database westos;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

+--------------------+

3 rows in set (0.00 sec)

insert into linux values (‘user1‘,‘passwd1‘); 在linux表中插入值为username = user1,password = password1

update linux set password=password(‘passwd2‘) where username=user1;(此种改密方式后的密码为加密密文) 更新linux表中user1 的密码为password2

update linux set password=‘passwd2‘ where username=user1;(此种修改方式后的密码为明文可见) 更新linux表中user1 的密码为password2

delete from linux where username=user1; 删除linux表中user1的所以内容

grant select on  *.* to [email protected] identified by ‘passwd1‘; 授权user1 密码为passwd1  并且只能在本地 查询数据库的所以内容

grant all on mysql.* to [email protected]‘%‘ identified by ‘passwd2‘; 授权user2 密码为passwd2  可以从远程任意主机登录mysql 并且可以对mysql数据库任意操作

2.备份

/var/lib/mysql

mysqldump -uroot -predhat mysql > mysql.bak 备份mysql库到mysql.bak

mysql -uroot -predhat westos < mysql.bak 恢复mysql.bak 到westos库

备份实例:

[[email protected] ~]# mysql -uroot -predhat

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 8

MariaDB [(none)]> SHOW DATABASES;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

+--------------------+

3 rows in set (0.00 sec)

MariaDB [(none)]> CREATE DATABASE westos;

Query OK, 1 row affected (0.00 sec)

MariaDB [(none)]> USE westos;

MariaDB [westos]> CREATE TABLE lzt (username varchar(10) not null,password varchar(10) not null,age varchar(4));

Query OK, 0 rows affected (0.07 sec)

MariaDB [westos]> show databases;

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

| westos             |

+--------------------+

4 rows in set (0.00 sec)

MariaDB [westos]> show lzt;

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ‘lzt‘ at line 1

MariaDB [westos]> desc lzt;

+----------+-------------+------+-----+---------+-------+

| Field    | Type        | Null | Key | Default | Extra |

+----------+-------------+------+-----+---------+-------+

| username | varchar(10) | NO   |     | NULL    |       |

| password | varchar(10) | NO   |     | NULL    |       |

| age      | varchar(4)  | YES  |     | NULL    |       |

+----------+-------------+------+-----+---------+-------+

3 rows in set (0.00 sec)

MariaDB [westos]> insert into lzt values(‘lp‘,‘westos‘,20);

Query OK, 1 row affected (0.34 sec)

MariaDB [westos]> select * from lzt;

+----------+----------+------+

| username | password | age  |

+----------+----------+------+

| lp       | westos   | 20   |

+----------+----------+------+

1 row in set (0.01 sec)

MariaDB [westos]> quit

Bye

[[email protected] ~]# mysqldump -uroot -predhat westos

-- MySQL dump 10.14  Distrib 5.5.35-MariaDB, for Linux (x86_64)

--

-- Host: localhost    Database: westos

-- ------------------------------------------------------

-- Server version 5.5.35-MariaDB

/*!40101 SET @[email protected]@CHARACTER_SET_CLIENT */;

/*!40101 SET @[email protected]@CHARACTER_SET_RESULTS */;

/*!40101 SET @[email protected]@COLLATION_CONNECTION */;

/*!40101 SET NAMES utf8 */;

/*!40103 SET @[email protected]@TIME_ZONE */;

/*!40103 SET TIME_ZONE=‘+00:00‘ */;

/*!40014 SET @[email protected]@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;

/*!40014 SET @[email protected]@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;

/*!40101 SET @[email protected]@SQL_MODE, SQL_MODE=‘NO_AUTO_VALUE_ON_ZERO‘ */;

/*!40111 SET @[email protected]@SQL_NOTES, SQL_NOTES=0 */;

--

-- Table structure for table `lzt`

--

DROP TABLE IF EXISTS `lzt`;

/*!40101 SET @saved_cs_client     = @@character_set_client */;

/*!40101 SET character_set_client = utf8 */;

CREATE TABLE `lzt` (

`username` varchar(10) NOT NULL,

`password` varchar(10) NOT NULL,

`age` varchar(4) DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=latin1;

/*!40101 SET character_set_client = @saved_cs_client */;

--

-- Dumping data for table `lzt`

--

LOCK TABLES `lzt` WRITE;

/*!40000 ALTER TABLE `lzt` DISABLE KEYS */;

INSERT INTO `lzt` VALUES (‘lp‘,‘westos‘,‘20‘);

/*!40000 ALTER TABLE `lzt` ENABLE KEYS */;

UNLOCK TABLES;

/*!40103 SET [email protected]_TIME_ZONE */;

/*!40101 SET [email protected]LD_SQL_MODE */;

/*!40014 SET [email protected]_FOREIGN_KEY_CHECKS */;

/*!40014 SET [email protected]_UNIQUE_CHECKS */;

/*!40101 SET [email protected]_CHARACTER_SET_CLIENT */;

/*!40101 SET [email protected]_CHARACTER_SET_RESULTS */;

/*!40101 SET [email protected]_COLLATION_CONNECTION */;

/*!40111 SET [email protected]_SQL_NOTES */;

-- Dump completed on 2016-11-26 21:32:12

[[email protected] ~]# mysqldump -uroot -predhat westos > /mnt/westos.sql

[[email protected] ~]# mysql -uroot -predhat -e "show databases;"

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

| westos             |

+--------------------+

[[email protected] ~]# mysql -uroot -predhat -e "drop database westos;"

[[email protected] ~]# mysql -uroot -predhat -e "show databases;"

+--------------------+

| Database           |

+--------------------+

| information_schema |

| mysql              |

| performance_schema |

+--------------------+

[[email protected] ~]# mysql -uroot -predhat westos < /mnt/westos.sql

ERROR 1049 (42000): Unknown database ‘westos‘

[[email protected] ~]# mysql -uroot -predhat -e "create database westos;"

[[email protected] ~]# mysql -uroot -predhat westos < /mnt/westos.sql

[[email protected] ~]# mysql -uroot -predhat -e "select * from westos.lzt;"

+----------+----------+------+

| username | password | age  |

+----------+----------+------+

| lp       | westos   | 20   |

+----------+----------+------+

3.mysql 密码恢复

systmctl stop  mariadb

mysqld_safe --skip-grant-tables & 跳过grant-tables授权表  不需要认证登录本地mysql数据库

update mysql.user set password=password(‘westos‘) where user=‘root‘; 更新mysql.user 表中条件为root用户的密码为加密westos

systemctl restart mariadb

忘记密码实例:

systemctl stop mariadb

mysqld_safe --skip-grant-tables &

mysql -uroot

MariaDB [(none)]> UPDATE mysql.user set Password=password (‘westos‘) WHERE User=‘root‘;

MariaDB [(none)]> quit

Bye

[[email protected] ~]# fg

mysqld_safe --skip-grant-tables

^Z

[1]+  Stopped                 mysqld_safe --skip-grant-tables

[[email protected] ~]# killall -9 1

1: no process found

[[email protected] ~]# killall -9 mysqld_safe

[1]+  Killed                  mysqld_safe --skip-grant-tables

[[email protected] ~]# ps aux | grep mysql

mysql     2616  0.1  5.0 859060 95360 pts/0    Sl   20:52   0:00 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --user=mysql --skip-grant-tables --log-error=/var/log/mariadb/mariadb.log --pid-file=/var/run/mariadb/mariadb.pid --socket=/var/lib/mysql/mysql.sock

root      2684  0.0  0.0 112640   936 pts/0    R+   20:57   0:00 grep --color=auto mysql

[[email protected] ~]# kill -9 2616

[[email protected] ~]# ps aux | grep mysql

root      2694  0.0  0.0 112640   932 pts/0    R+   20:58   0:00 grep --color=auto mysql

[[email protected] ~]# systemctl start mariadb

[[email protected] ~]# mysql -uroot -pwestos

MariaDB [(none)]> quit

Bye

[[email protected] ~]# mysqladmin -uroot -pwestos password redhat

[[email protected] ~]# mysql -uroot -predhat

phpmyadmin

yum install php php-mysql httpd mysql mysql-server

tar jxf phpmyadmin-*.tar.bz2 -C /var/www/html

mv phpmyadmin phpadmin

cp config.sample.inc.php config.inc.php

vim config.inc.php

add

$cfg[‘blowfish_secret‘] = ‘test‘;

4.创建用户

(‘localhost‘表示‘本地‘,‘%‘表示‘服务器端‘,‘identified‘ 表示 ‘密码‘)

CREATE USER [email protected] identified by ‘westos‘; ##创建本地用户,并设置密码

CREATE USER [email protected]‘%‘ identified by ‘redhat‘; ##创建服务器端用户(只要有账户和密码,就可以在数据库开放的主机上登录)

用户授权

GRANT INSERT,UPDATE,DELETE,SELECT on mariadb.* to [email protected];

GRANT SELECT on mariadb.* [email protected]‘%‘;

重载授权表

FLUSH PRIVILEGES;

查看用户授权

SHOW GRANTS FOR [email protected];

撤销用户权限

REVOKE DELETE,UPDATE,INSERT on mariadb.* from [email protected];

删除用户

DROP USER [email protected];

实例:

[[email protected] ~]# mysql -uroot -predhat

Welcome to the MariaDB monitor.  Commands end with ; or \g.

MariaDB [(none)]> CREATE USER [email protected] identified by ‘lzt‘;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> quit;

Bye

[[email protected] ~]# mysql -ulzt -plzt

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 3

MariaDB [(none)]> CREATE DATABASE nihao;

ERROR 1044 (42000): Access denied for user ‘lzt‘@‘localhost‘ to database ‘nihao‘

MariaDB [(none)]> quit;

Bye

[[email protected] ~]# mysql -uroot -predhat

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 4

MariaDB [(none)]> GRANT CREATE on *.* to [email protected];

Query OK, 0 rows affected (0.01 sec)

MariaDB [(none)]> GRANT SELECT on *.* to [email protected];

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> SHOW GRANTS FOR [email protected];

+---------------------------------------------------------------------------------------------------------------------+

| Grants for [email protected]                                                                                            |

+---------------------------------------------------------------------------------------------------------------------+

| GRANT SELECT, CREATE ON *.* TO ‘lzt‘@‘localhost‘ IDENTIFIED BY PASSWORD ‘*0B5204298A57D2948EB6AF6312B83D940E6D4C9F‘ |

+---------------------------------------------------------------------------------------------------------------------+

1 row in set (0.00 sec)

MariaDB [(none)]> FLUSH PRIVILEGES;

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> GRANT INSERT on *.* to [email protected];

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> SHOW GRANTS FOR [email protected];

+-----------------------------------------------------------------------------------------------------------------------------+

| Grants for [email protected]                                                                                                    |

+-----------------------------------------------------------------------------------------------------------------------------+

| GRANT SELECT, INSERT, CREATE ON *.* TO ‘lzt‘@‘localhost‘ IDENTIFIED BY PASSWORD ‘*0B5204298A57D2948EB6AF6312B83D940E6D4C9F‘ |

+-----------------------------------------------------------------------------------------------------------------------------+

1 row in set (0.01 sec)

MariaDB [(none)]> SHOW GRANTS FOR [email protected];

+-----------------------------------------------------------------------------------------------------------------------------+

| Grants for [email protected]                                                                                                    |

+-----------------------------------------------------------------------------------------------------------------------------+

| GRANT SELECT, INSERT, CREATE ON *.* TO ‘lzt‘@‘localhost‘ IDENTIFIED BY PASSWORD ‘*0B5204298A57D2948EB6AF6312B83D940E6D4C9F‘ |

+-----------------------------------------------------------------------------------------------------------------------------+

1 row in set (0.00 sec)

MariaDB [(none)]> SELECT * FROM mysql.user;

+-----------+------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------

| Host      | User | Password                                  | Select_priv | Insert_priv | Update_priv | Delete_priv | Create_priv | Drop_priv | Reload_priv | Shutdown_priv | Process_priv | File_priv | Grant_priv | References_priv | Index_priv | Alter_priv | Show_db_priv | Super_priv | Create_tmp_table_priv | Lock_tables_priv | Execute_priv | Repl_slave_priv | Repl_client_priv | Create_view_priv | Show_view_priv | Create_routine_priv | Alter_routine_priv | Create_user_priv | Event_priv | Trigger_priv | Create_tablespace_priv | ssl_type | ssl_cipher | x509_issuer | x509_subject | max_questions | max_updates | max_connections | max_user_connections | plugin | authentication_string |

+-----------+------+-------------------------------------------+-------------+-------------+-------------+-------------+-------------+-----------+-------------+---------------

| localhost | root | *84BB5DF4823DA319BBF86C99624479A198E6EEE9 | Y           | Y           | Y           | Y           | Y           | Y         | Y           | Y             | Y            | Y         | Y          | Y               | Y          | Y          | Y            | Y          | Y                     | Y                | Y            | Y               | Y                | Y                | Y              | Y                   | Y                  | Y                | Y          | Y            | Y                      |          |            |             |              |             0 |           0 |               0 |                    0 |        |                       |

| localhost | lzt  | *0B5204298A57D2948EB6AF6312B83D940E6D4C9F | Y           | Y           | N           | N           | Y           | N         | N           | N             | N            | N         | N          | N               | N          | N          | N            | N          | N                     | N                | N            | N               | N                | N                | N              | N                   | N                  | N                | N          | N            | N                      |          |            |             |              |             0 |           0 |               0 |                    0 |        |                       |

4 rows in set (0.00 sec)

MariaDB [(none)]> REVOKE CREATE on *.* from [email protected];

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> REVOKE INSERT on *.* from [email protected];

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> REVOKE SELECT on *.* from [email protected];

Query OK, 0 rows affected (0.00 sec)

MariaDB [(none)]> DROP USER [email protected];

Query OK, 0 rows affected (0.00 sec)

5.图形管理数据库:

[[email protected] ~]# yum install httpd -y

[[email protected] ~]# cd /var/www/html/

[[email protected] html]# lftp 172.25.254.250

lftp 172.25.254.250:~> cd pub/

lftp 172.25.254.250:/pub> cd docs

cd ok, cwd=/pub/docs

lftp 172.25.254.250:/pub/docs> cd software/

lftp 172.25.254.250:/pub/docs/software> get phpMyAdmin-3.4.0-all-languages.tar.bz2

4548030 bytes transferred

lftp 172.25.254.250:/pub/docs/software> quit

[[email protected] html]# ls

phpMyAdmin-3.4.0-all-languages.tar.bz2

[[email protected] html]# tar -jxf phpMyAdmin-3.4.0-all-languages.tar.bz2

[[email protected] html]# ls

phpMyAdmin-3.4.0-all-languages  phpMyAdmin-3.4.0-all-languages.tar.bz2

[[email protected] html]# rm -fr phpMyAdmin-3.4.0-all-languages.tar.bz2

[[email protected] html]# ls

phpMyAdmin-3.4.0-all-languages

[[email protected] html]# firewall-cmd --permanent --add-service=http

success

[[email protected] html]# firewall-cmd --reload

success

[[email protected] html]# yum install php -y

[[email protected] html]# yum install php-mysql.x86_64 -y

[[email protected] html]# mv phpMyAdmin-3.4.0-all-languages myadmin

[[email protected] html]# cp -p config.sample.inc.php config.inc.php

[[email protected] myadmin]# vim config.inc.php

修改第 17 行:

$cfg[‘blowfish_secret‘] = ‘westos‘;(此处添加任意字符即可) /* YOU MUST FILL IN THIS FOR COOKIE AUTH! *    /

[[email protected] myadmin]# systemctl start httpd

[[email protected] myadmin]# ifconfig

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500

inet 172.25.254.207  netmask 255.255.0.0  broadcast 172.25.255.255

测试:

在另外一台主机的浏览器里输入 172.25.254.207/myadmin 即可登录数据库

#############配置电子邮件的传输########

1.基础配置

server主机:

修改ip为 172.25.254.207

systemctl restart network

配置yum源为 172.25.254.250/rhel7

vim /etc/resolv.conf

添加内容为: nameserver 172.25.254.107

修改主机名为 mailwestos.westos.com

desktop主机:

修改ip为 172.25.254.107

systemctl restart network

配置yum源为 172.25.254.250/rhel7

vim /etc/resolv.conf

添加内容为: nameserver 172.25.254.107

修改主机名为 maillinux.linux.com

下载dns服务:

yum install bind -y

配置 /etc/named.conf文件

11 //      listen-on port 53 { 127.0.0.1; };

12 //      listen-on-v6 port 53 { ::1; };

17 //      allow-query     { localhost; };

32         nssec-validation no;

配置/etc/named.rfc1912.zones

先对模块复制两次(y6y --> p)

26 zone "westos.com" IN {

27         type master;

28         file "westos.com.zone";

29         allow-update { none; };

30 };

31 zone "linux.com" IN {

32         type master;

33         file "linux.com.zone";

34         allow-update { none; };

35 };

cp -p named.localhost westos.com.zone

配置 /var/named/westos.com.zone 文件为:

$TTL 1D

@       IN SOA  dns.westos.com root.westos.com. (

0       ; serial

1D      ; refresh

1H      ; retry

1W      ; expire

3H )    ; minimum

NS      dns.westos.com.

dns             A       172.25.254.107

westos.com.     MX 1    172.25.254.207.

cp -p westos.com.zone linux.com.zone

配置 /var/named/westos.com.zone 文件为:

$TTL 1D

@       IN SOA  dns.westos.com root.westos.com. (

0       ; serial

1D      ; refresh

1H      ; retry

1W      ; expire

3H )    ; minimum

NS      dns.westos.com.

dns             A       172.25.254.107

linux.com.      MX 1    172.25.254.107.

systemctl restart named

systemctl stop firewalld

测试:

dig -t MX westos.com

dig -t MX linux.com

2.邮件服务配置

desktop端:

vim /etc/postfix/main.cf

内容为:

75 myhostname = maillinux.linux.com

83 mydomain = linux.com

99 myorigin = $mydomain

113 inet_interfaces = all

116 #inet_interfaces = localhost

164 mydestination = $myhostname, $mydomain, localhost

server端:

75 myhostname = mailwestos.westos.com

83 mydomain = westos.com

99 myorigin = $mydomain

113 inet_interfaces = all

116 #inet_interfaces = localhost

164 mydestination = $myhostname, $mydomain, localhost

3.别名发送:

要求:

desktop(linux.com) 主机向 server(westos.com)主机发送邮件,使用别名发送:mail [email protected] (server主机里没有lzt用户)

此时需要配置接收方(server主机) /etc/aliases

97 lzt:            root ##别名

98 all:    :include:/etc/alluser ##群发

vim /etc/alluser 修改内容为:

root

student

postalias /etc/aliases

systemctl restart postfix.service

测试:

使用dekstop主机发送邮件

mail [email protected]

mail [email protected]

4.出站地址伪装

server (westos.com)主机:

vim /etc/postfix/generic 修改内容为:

在最后一行添加:[email protected] [email protected]

postmap /etc/postfix/generic

postconf -d | grep generic 会出来一段字符,选择最后的一行字符(如下),进行复制:

smtp_generic_maps =

postconf -e "smtp_generic_maps = hash:/etc/postfix/generic" ##此处用到上条语句复制的字符

systemctl restart postfix.servic

测试:

使用server(westos.com)向dsktop(linux.com)主机:

mail [email protected]

在dsktop(linux.com)主机查看邮件来源

实例结果:

[[email protected] postfix]# mail [email protected] ##在westos.com上操作

Subject: tt

gg

.

EOT

[[email protected] named]# mail ##在linux.com上操作

>N  5 root                  Sun Nov 27 03:38  21/741   "tt"

& 5

Message  5:

From [email protected]  Sun Nov 27 03:38:39 2016

Return-Path: <[email protected]>

X-Original-To: [email protected]

5.检测25端口

软件下载 yum install telnet -y

测试 telnet 172.25.254.207 25

Trying 172.25.254.207...

Connected to 172.25.254.207.

Escape character is ‘^]‘.

220 mailwestos.westos.com ESMTP Postfix

ehlo hello ##打招呼,检测端口是否正常,若出现下面 250 信息,则表示正常

250-mailwestos.westos.com

250-PIPELINING

250-SIZE 10240000

250-VRFY

250-ETRN

250-ENHANCEDSTATUSCODES

250-8BITMIME

250 DSN

mail from:[email protected] ##邮件的发送方

250 2.1.0 Ok

rcpt to:[email protected] ##邮件的接收方

250 2.1.5 Ok

data ##邮件名字

354 End data with <CR><LF>.<CR><LF>

ddd ##邮件内容

fff

.

250 2.0.0 Ok: queued as 38E0C17E849

quit ##退出telnet

221 2.0.0 Bye

Connection closed by foreign host.

实例:

在真机上做测验:

[[email protected] ~]# yum install telnet -y

[[email protected] ~]# telnet 172.25.254.207 25

Trying 172.25.254.207...

Connected to 172.25.254.207.

Escape character is ‘^]‘.

220 mailwestos.westos.com ESMTP Postfix

ehlo hello

250-mailwestos.westos.com

250-PIPELINING

250-SIZE 10240000

250-VRFY

250-ETRN

250-ENHANCEDSTATUSCODES

250-8BITMIME

250 DSN

mail from:[email protected]

250 2.1.0 Ok

rcpt to:[email protected]

250 2.1.5 Ok

data

354 End data with <CR><LF>.<CR><LF>

ddd

fff

.

250 2.0.0 Ok: queued as 38E0C17E849

quit

221 2.0.0 Bye

Connection closed by foreign host.

在linux.com主机上查看邮件

[[email protected] named]# mail

Heirloom Mail version 12.5 7/5/10.  Type ? for help.

"/var/spool/mail/root": 6 messages 1 new 3 unread

5 root                  Sun Nov 27 03:38  22/752   "tt"

>N  6 [email protected]     Sun Nov 27 04:03  14/505 ##此处显示邮件发送方为 [email protected] 是因为在westos.com上有出站地址伪装

& 6

Message  6:

From [email protected]  Sun Nov 27 04:03:11 2016

Return-Path: <[email protected]>

X-Original-To: [email protected]

Delivered-To: [email protected]

Status: R

ddd

fff

& q

Held 6 messages in /var/spool/mail/root

You have mail in /var/spool/mail/root

时间: 2024-08-01 00:18:15

笔记九的相关文章

老男孩培训视频听课笔记九(在51cto上听的)--5.8 64bit 基础优化

定时清理clientmqueue目录垃圾文件防止占满磁盘空间: /var/spool/clientmqueue  --这个目录会自动创建很多的文件,可以用下面的命令来清理 find /var/spool/clientmqueue/ –type  f | xargs rm –fr mkdir /server/scripts –p vim del.sh: find /var/spool/clientmqueue/ –type  f | xargs rm –fr crontab -e */5 * *

APUE 学习笔记(九) 高级I/O

1. 非阻塞I/O 低速系统调用时可能会使进程永远阻塞的一类系统调用,包括以下调用: (1)某些文件类型你(网络socket套接字.终端设备.管道)暂无可使用数据,则读操作可能会使调用者永远阻塞 (2)如果数据不能立即被(1)中文件类型接受,则写操作会使调用者永远阻塞 (3)某些进程间通信函数 非阻塞I/O使我们可以调用open.read.write这样的I/O操作,并使这些操作不会永远阻塞,如果这种操作不能完成,则调用立即出错返回 对于一个给定的文件有两种方法对其指定非阻塞I/O: (1)调用

python学习笔记九——文件与目录

1.python进行文件读写的函数是open或file类 mode:r  只读 r+   读写 w  写入,先删除原文件,再重新写入,如果文件没有则创建 w+  读写,先删除原文件,再重新写入,如果文件没有则创建(可写入和输出) a  写入,在文件末尾追加新的内容,文件不存在则创建 a+  读写,在文件末尾追加新的内容,文件不存在则创建 b  打开二进制文件,可与r,w,a,+结合使用 U  支持所有的换行符号,"\r","\n","\r\n"

angular学习笔记(九)-css类和样式3

再来看一个选择li列表的例子: 点击li中的任意项,被点击的li高亮显示: <!DOCTYPE html> <html ng-app> <head> <title>6.3css类和样式</title> <meta charset="utf-8"> <script src="../angular.js"></script> <script src="scri

angular学习笔记(九)-css类和样式2

在上一个例子中,元素的类名使用拼接的方法,这样,类名中就不得不带有true或false,并且不易维护,所以,angular使用ng-class属性来控制元素的类名: 我们来看一个小例子,点击error按钮,顶部提示错误框,点击warning按钮,顶部提示警告框. 错误框的类名是.err,警告框的类名是.warn: <!DOCTYPE html> <html ng-app> <head> <title>6.2css类和样式</title> <

jQuery整理笔记九----功能性表格开发

示例中用到的一些图片.插件.样式文件等下载地址:点我进入下载 过去在开发过程中关于table方面的jquery应用仅仅是局限于使用jquery操作table增加一行.删除一列等等操作.今天整理的跟过去用的不一样. 1.uiTableFilter uiTableFilter是一款表格数据行过滤插件,使用很简单,具体用法如下: $.uiTableFilter(table,phrase)  该函数包含两个参数,其中第一个参数为jQuery对象,即为jQuery方法匹配的表格,或者也可以是jQuery匹

Linux System Programming 学习笔记(九) 内存管理

1. 进程地址空间 Linux中,进程并不是直接操作物理内存地址,而是每个进程关联一个虚拟地址空间 内存页是memory management unit (MMU) 可以管理的最小地址单元 机器的体系结构决定了内存页大小,32位系统通常是 4KB, 64位系统通常是 8KB 内存页分为 valid or invalid: A valid page is associated with an actual page of data,例如RAM或者磁盘上的文件 An invalid page is

Elasticsearch笔记九之优化

Elasticsearch笔记九之优化 优化从索引片段,内存设置,副本,分片,日志等方面入手.1:索引片段Es运行时会生成很多索引片段,执行查询时会打开这些索引片断.系统会限制打开索引片断的个数一旦超过这个个数限制就无法打开索引片断.我们可以通过命令来查看更改索引片断的限制数量.索引片断位置/usr/local/elasticsearch-1.4.4/data/elasticsearch/nodes/0/indices/shb01/0/index ulimit –a 查看索引片断数量,默认是10

虚拟机VMWare学习笔记九 - 物理机上的文件挂载到虚拟机上

物理机上的文件夹或盘符直接挂载到虚拟机上使用. VM -- Settings Options -- Shared Folders -- 勾选Always enabled , 勾选Map as a network drive in Windows guests 在点击下面的添加来添加共享的文件夹 选择路径 可以看到虚拟机中的共享文件夹已经出现在Windows 中了 虚拟机VMWare学习笔记九 - 物理机上的文件挂载到虚拟机上

初探swift语言的学习笔记九(OC与Swift混编)

swift 语言出来后,可能新的项目直接使用swift来开发,但可能在过程中会遇到一些情况,某些已用OC写好的类或封装好的模块,不想再在swift 中再写一次,哪就使用混编.这个在IOS8中是允许的. 先中简单的入手,先研究在同一个工程目录下混合使用的情况. 为了演示.先准备两个类 第一个是swift语言写的类,文件名为 act.swift import Foundation class Act : NSObject { func hasAct(tag:Int) -> String { swit