分类 Linux 下的文章

基础语法

使用前记得给文件加上x权限
第一行加解释器，格式如

#!/bin/sh

变量

定义变量

var1="123"

使用语句给变量赋值

for file in `ls /etc`

使用变量使用$

#!/bin/sh
var1="hello world"
echo $var1

当然，当你的变量和句子混在一起的时候，你可以使用${}来帮助解释变量范围，就像这样

#!/bin/sh
var1=" hello world"
echo "I want to say${var1}"

字符串

单引号中的所有字符都会原样输出，而双引号中的变量、转义字符等都可以被解释，单引号中不能有单引号，转义了的也不行

[root@master shtest]# ./test1.sh 
I want to say${var1}
[root@master shtest]# cat test1.sh 
#!/bin/sh
var1=" hello world"
echo 'I want to say${var1}'

拼接字符串

[root@master shtest]# ./test1.sh 
hello worldnihao, hello world
[root@master shtest]# cat test1.sh 
#!/bin/sh
var1=" hello world"
var2="nihao,$var1"
echo $var1$var2

输出字符串长度${#}

[root@master shtest]# cat test1.sh 
#!/bin/sh
var1=" hello world"
var2="nihao,$var1"
echo ${#var2}
[root@master shtest]# ./test1.sh 
18

字符串切片

[root@master shtest]# ./test1.sh 
nihao
[root@master shtest]# cat test1.sh 
#!/bin/sh
var1=" hello world"
var2="nihao,$var1"
echo ${var2:0:5}

概念

https://blog.51cto.com/u_15048360/3202204
ansible是由python开发的自动化运维工具，是极限了了批量部署、命令执行等功能，ansible是基于模块工作的，本身只提供一个框架

核心组件：
ansible:核心程序
modules:核心模块及自定义模块
plugins:补充插件，如邮箱插件
playbooks:剧本，定义多任务配置文件，由ansible自动执行
inventory:定义管理的主机清单
connection plugins:负责和被监控端实现通信

特点：
无需再被监控端上安装agent
无服务器端
基于模块工作
使用yaml
基于ssh

执行过程：
加载配置文件，默认为/etc/ansible/ansible.cfg
加载模块文件
通过ansible将模块或命令生成对应的临时python文件并将文件传输至远程服务器
执行用户家目录的.ansible/tmp/.py文件
给文件+x
执行并返回结果，删除临时python文件，退出

使用

基础

安装

yum install epel-release.noarch -y
yum install ansible -y

配置免密

ssh-keygen
cat ~/.ssh/id_rsa.pub
在被操作机上
vi /root/.ssh/authorized_keys

配置文件

ls /etc/ansible/
ansible.cfg  hosts  roles

cat ansible.cfg
[defaults]

# some basic default values...

#主机清单
#inventory      = /etc/ansible/hosts
#文件存放位置
#library        = /usr/share/my_modules/
#module_utils   = /usr/share/my_module_utils/
#临时生成的文件在远程主机上的目录
#remote_tmp     = ~/.ansible/tmp
#临时生成的文件在本地主机的目录
#local_tmp      = ~/.ansible/tmp
#plugin_filters_cfg = /etc/ansible/plugin_filters.yml
#默认并发数
#forks          = 5
#默认线程数
#poll_interval  = 15
#sudo_user      = root
#ask_sudo_pass = True
#ask_pass      = True
#transport      = smart
#remote_port    = 22
#module_lang    = C
#module_set_locale = False

vi hosts
# This is the default ansible 'hosts' file.
#
# It should live in /etc/ansible/hosts
#
#   - Comments begin with the '#' character
#   - Blank lines are ignored
#   - Groups of hosts are delimited by [header] elements
#   - You can enter hostnames or ip addresses
#   - A hostname/ip can be a member of multiple groups

# Ex 1: Ungrouped hosts, specify before any group headers.

## green.example.com
## blue.example.com
## 192.168.100.1
## 192.168.100.10

# Ex 2: A collection of hosts belonging to the 'webservers' group

## [webservers]
## alpha.example.org
## beta.example.org
## 192.168.1.100
## 192.168.1.110

# If you have multiple hosts following a pattern you can specify
# them like this:

## www[001:006].example.com

# Ex 3: A collection of database servers in the 'dbservers' group

## [dbservers]
##
## db01.intranet.mydomain.net
## db02.intranet.mydomain.net
## 10.25.1.56
## 10.25.1.57

# Here's another example of host ranges, this time there are no
# leading 0s:

## db-[99:101]-node.example.com

常用参数

-a :指定模块的参数
-m :指定模块
-C :坚持执行结果
-e :指明变量名
-f :指定并发进程数
-i :指定主机清单文件
--syntax-check：检查执行命令是否存在语法错误

ansible-doc -l 列出所有模块
ansible-doc [-s]  xx 查看指定模块的用法,-s为列出简单信息
ansible <host-pattern> [-m module_name] [-a args] 执行
ansible-playbook 执行剧本
ansible-console 交互执行

ansible localhost -m 本地执行

playbook

playbook使用yaml编写
https://ansible-tran.readthedocs.io/en/latest/docs/playbooks_intro.html
每一个play包含一个task列表，task会根据你配置的hosts\remote_user等使用指定的模块去运行设定的命名，运行时是自上向下的，每个task必须有一个名称以用于区分
比如这样的，使用shell模块运行命令

tasks:
  - name: run this command and ignore the result
    shell: /usr/bin/somecommand || /bin/true

我们用个完整点的例子来演示下
安装nginx并配置文件

第一步，准备文件存放目录
[root@master ~]# mkdir -p /root/ansible/{conf,bin}
第二步，书写YAML文件
[root@master bin]# cat nginx.yaml
- hosts: server2 #目标主机
  remote_user: root #在目标机上使用的账户
  vars: #变量
    hello: Ansible
  tasks: #第一个任务
  - name: Install epel #任务名
    yum:  #yum模块
      name: epel-release.noarch
      state: latest
  - name: Install nginx
    yum:
      name: nginx
      state: present
  - name: Copy nginx configure file
    copy: #copy模块
      src: /root/ansible/conf/site.conf
      dest: /etc/nginx/conf.d/site.conf
  - name: Start nginx
    service: #设置开机启动
      name: nginx
      state: restarted
  - name: Create index.html
    shell: echo "nginx1" > /usr/share/nginx/html/index.html

第三步，书写conf文件
[root@master bin]# cat site.conf
server {
listen 8080;
server_name 192.168.80.50:8080;
location / {
index index.html;
}
}
第四步，检查语法错误，没有错误则继续执行
[root@master bin]# ansible-playbook nginx.yaml --syntax-check
[root@master bin]# ansible-playbook nginx.yaml

当然，比起这种key: value，你也可以写成key=value的形式，不过注意并不是所有的模块都支持这种写法，比如说shell

---
- hosts: webservers
  vars:
    http_port: 80
    max_clients: 200
  remote_user: root
  tasks:
  - name: ensure apache is at the latest version
    yum: pkg=httpd state=latest
  - name: write the apache config file
    template: src=/srv/httpd.j2 dest=/etc/httpd.conf
    notify:
    - restart apache
  - name: ensure apache is running
    service: name=httpd state=started
  handlers:
    - name: restart apache
      service: name=httpd state=restarted

常用模块

ping:测试连通

[root@master ~]# vi /etc/ansible/hosts 
[root@master ~]# ansible -m ping test
172.17.120.142 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python"
    }, 
    "changed": false, 
    "ping": "pong"

shell：远程执行指令
https://bingostack.com/2021/03/ansible-shell-command/
https://docs.ansible.com/ansible/latest/collections/ansible/builtin/shell_module.html

ansible-doc -s shell
- name: Execute shell commands on targets
  shell:
      chdir:                 # Change into this directory before running the command.
      cmd:                   # The command to run followed by optional arguments.
      creates:               # A filename, when it already exists, this step will *not* be run.
      executable:            # Change the shell used to execute the command. This expects an absolute path to the executable.
      free_form:             # The shell module takes a free form command to run, as a string. There is no actual parameter named 'free form'. See the
                               examples on how to use this module.
      removes:               # A filename, when it does not exist, this step will *not* be run.
      stdin:                 # Set the stdin of the command directly to the specified value.
      stdin_add_newline:     # Whether to append a newline to stdin data.
      warn:                  # Whether to enable task warnings.

[root@master ~]# cat test-pwd.yaml 
- hosts: test
  tasks: 
  - name: ls tmp
    shell: cd /tmp && pwd && ls -l > ./log

[root@master ~]# ansible-playbook test-pwd.yaml --syntax-check

playbook: test-pwd.yaml
[root@master ~]# ansible-playbook test-pwd.yaml

[root@node01 ~]# cat /tmp/log 
total 8
srwxr-xr-x 1 root root    0 Feb  9 23:06 aliyun_assist_service.sock
drwx------ 2 root root 4096 Feb 23 17:01 ansible_command_payload_geujPy
-rw-r--r-- 1 root root    0 Feb 23 17:01 log
drwx------ 3 root root 4096 Feb  7 10:06 systemd-private-7cbd598af444427b8714fcd64c669e47-chronyd.service-Z4rJtW

service：配置开机自启

service:
      arguments:             # Additional arguments provided on the command line.
      enabled:               # Whether the service should start on boot. *At least one of state and enabled are required.*
      name:                  # (required) Name of the service.
      pattern:               # If the service does not respond to the status command, name a substring to look for as would be found in the output of the
                               `ps' command as a stand-in for a status result. If the string is found, the service will be
                               assumed to be started.
      runlevel:              # For OpenRC init scripts (e.g. Gentoo) only. The runlevel that this service belongs to.
      sleep:                 # If the service is being `restarted' then sleep this many seconds between the stop and start command. This helps to work
                               around badly-behaving init scripts that exit immediately after signaling a process to stop.
                               Not all service managers support sleep, i.e when using systemd this setting will be
                               ignored.
      state:                 # `started'/`stopped' are idempotent actions that will not run commands unless necessary. `restarted' will always bounce the
                               service. `reloaded' will always reload. *At least one of state and enabled are required.*
                               Note that reloaded will start the service if it is not already started, even if your chosen
                               init system wouldn't normally.
      use:                   # The service module actually uses system specific modules, normally through auto detection, this setting can force a
                               specific module. Normally it uses the value of the 'ansible_service_mgr' fact and falls

copy

  copy:
      backup:   覆盖文件前先备份
      content:  src
      dest:     目的目录

inotifywait

作者: matsudaira
时间: 2023-10-24
分类: Linux
评论

环境准备

https://www.jianshu.com/p/57e3819a2e7c
内核版本需要高于2.6.13
uname -r
使用ll /proc/sys/fs/inotify命令，是否有以下三条信息输出，如果没有表示不支持。

ll /proc/sys/fs/inotify

total 0
-rw-r--r-- 1 root root 0 Jan 4 15:41 max_queued_events
-rw-r--r-- 1 root root 0 Jan 4 15:41 max_user_instances
-rw-r--r-- 1 root root 0 Jan 4 15:41 max_user_watches

安装：
yum install inotify-tools

使用说明

inotify是一种监控工具，他用于监控一个文件直到某种指定的事件发生

inotifywait -h
inotifywait 3.14
Wait for a particular event on a file or set of files.
Usage: inotifywait [ options ] file1 [ file2 ] [ file3 ] [ ... ]
Options:
        -h|--help       Show this help text.
        @<file>         Exclude the specified file from being watched.
        --exclude <pattern>
                        Exclude all events on files matching the
                        extended regular expression <pattern>.
        --excludei <pattern>
                        Like --exclude but case insensitive.
        -m|--monitor    Keep listening for events forever.  Without
                        this option, inotifywait will exit after one
                        event is received.
        -d|--daemon     Same as --monitor, except run in the background
                        logging events to a file specified by --outfile.
                        Implies --syslog.
        -r|--recursive  Watch directories recursively.
        --fromfile <file>
                        Read files to watch from <file> or `-' for stdin.
        -o|--outfile <file>
                        Print events to <file> rather than stdout.
        -s|--syslog     Send errors to syslog rather than stderr.
        -q|--quiet      Print less (only print events).
        -qq             Print nothing (not even events).
        --format <fmt>  Print using a specified printf-like format
                        string; read the man page for more details.
        --timefmt <fmt> strftime-compatible format string for use with
                        %T in --format string.
        -c|--csv        Print events in CSV format.
        -t|--timeout <seconds>
                        When listening for a single event, time out after
                        waiting for an event for <seconds> seconds.
                        If <seconds> is 0, inotifywait will never time out.
        -e|--event <event1> [ -e|--event <event2> ... ]
                Listen for specific event(s).  If omitted, all events are 
                listened for.

Exit status:
        0  -  An event you asked to watch for was received.
        1  -  An event you did not ask to watch for was received
              (usually delete_self or unmount), or some error occurred.
        2  -  The --timeout option was given and no events occurred
              in the specified interval of time.

Events:
        access          file or directory contents were read
        modify          file or directory contents were written
        attrib          file or directory attributes changed
        close_write     file or directory closed, after being opened in
                        writeable mode
        close_nowrite   file or directory closed, after being opened in
                        read-only mode
        close           file or directory closed, regardless of read/write mode
        open            file or directory opened
        moved_to        file or directory moved to watched directory
        moved_from      file or directory moved from watched directory
        move            file or directory moved to or from watched directory
        create          file or directory created within watched directory
        delete          file or directory deleted within watched directory
        delete_self     file or directory was deleted
        unmount         file system containing file or directory unmounted

nginx支持的信号表

SIGNALS
     The master process of nginx can handle the following signals:
     SIGINT, SIGTERM  Shut down quickly.
     SIGHUP           Reload configuration, start the new worker process with a new configuration, and gracefully shut
                      down old worker processes.
     SIGQUIT          Shut down gracefully.
     SIGUSR1          Reopen log files.
     SIGUSR2          Upgrade the nginx executable on the fly.
     SIGWINCH         Shut down worker processes gracefully.
     
# 可以使用nginx -s，也可以使用kill，需要注意互相之间的映射关系
#http://io.upyun.com/2017/08/19/nginx-signals/