Ansible overview and module explanation (you just passed today, but yesterday came to your face)

Preface

The commonly used automatic chemical industry has ：

• ansible
• saltstack
• puppet

These three are automation tools , It can be used to improve the efficiency of operation and maintenance management , Among the three operation and maintenance tools, the mainstream is ansible and saltstack.ansible and saltstack The difference is that ansible No need to install client , It also became ansible A big advantage of ; and saltstack You need to install the client , You don't have to install it , Their applicable scenarios are also different ,ansible For small businesses , Applicable when managing fewer servers ,saltstack For medium and large enterprises , because ansible Cannot execute in parallel saltstack Can be executed in parallel . But these three operation and maintenance tools have no advantages or disadvantages , Only the applicable scenarios are different .

One 、Ansible summary

1.1 Ansible Introduce

Ansible It's based on Python Development of configuration management and application deployment tools , Now it's also playing a great role in the field of automation management . It integrates the advantages of many old operation and maintenance tools ,Pubbet and Saltstack Functions that can be realized ,Ansible Basically all can be achieved .

1.2 Ansible What can be done

Ansible Can batch To configure 、 Deploy 、 Manage thousands of hosts . For example, you need to switch to one or more operations performed on each host before , Use Ansible Just a fixed one Ansible Control node to complete all host operations .

Ansible yes Module based work Of , It just provides a framework to run , It doesn't have the ability to complete the task itself , The real thing to do is Ansible Module , such as copy Module is used to copy files to the remote host ,service Module is used to manage the start of the service 、 stop it 、 Restart, etc. .

1.3 Why choose Ansible

Ansible since 2012 Since its release , It didn't take long for it to become popular in the United States . Be quickly IT The reason why people accept it is largely due to Michael DeHaan In the U.S. IT The fame and influence of the circle . Then it gradually became popular in various countries . The author chose Ansible The main reasons are as follows ：

• Ansible Based solely on Python Development , and DevOps It is already a trend in China ,Python Gradually popularized , The threshold for O & M personnel to develop tools by themselves is gradually reduced , Thanks to this , Convenience is right Ansible Secondary development ;
• Ansible Rich built-in modules , There are even functional modules specially developed for business platforms , near 600 Modules can completely meet the needs of daily functions ;
• stay Ansible Under the concept of decentralization , A simple copy operation can complete the migration of the management configuration center ;
• Agentless（ No client ）, The client does not need any configuration , It can be used after being configured by the management end , This is very attractive . In the 10 Chapter describes how to deploy the configuration Windows The host side of the system , You will feel deeply after using .
• since Ansible After the release of , And then AWS、Google CloudPlatform、Microsoft Azure、Cisco、HP、VMware、Twitter Wait for big companies to accept and put into use .

1.4 Two characteristics

1. agentless： There is no need to install additional client software , Just install on one host anaible You can pass ash Control remote host ansib1c Operations are performed through modules
2. Idempotency ;ansible Many modules will judge whether the remote host has performed this task , If it has been executed and the operation has not changed , Will not implement the change results

1.5 Ansible framework

Ansible Between the management node and the remote host node SSH Protocol to communicate . So configuration Ansible When , Just guarantee from Ansible Management node through SSH The protocol can connect to the managed remote node . Be careful ,SSH Must be configured for public key authentication login mode , Not password authentication .

Ansible It can be managed at the same time Red Hat Systematic Linux、Debian Systematic Linux as well as Windows host .Ansible The working principle of is shown in the figure .

Two 、 Deploy Ansible

Server type	IP Address	Software to install
Ansible Management server	192.168.109.138	Ansible
Managed client	192.168.109.131	------
Managed client	192.168.109.132	------

2.1 install ansible service

[[email protected] ~]#yum install -y epel-release
[[email protected] ~]#yum install -y ansible

[[email protected] ~]# cd /etc/ansible/
[[email protected] ansible]# ls
ansible.cfg  hosts  roles
----------------------------------------------------------------
ansible.cfg		# ansible Configuration file for , Generally, there is no need to modify 
hosts			# ansible List of hosts , For storing information about remote hosts that need to be managed 
roles			#  Public role Directory 

2.2 Configure host list

vim /etc/ansible/hosts				
[webservers]		# Configuration group name 
192.168.109.131		# The managed hosts included in the Group IP Address or host name （ The host name needs to be modified first /etc/hosts file ）
[dbservers]
192.168.109.132

2.3 Configure key pair validation

# Generate key pair （ Enter all the way ）
ssh-keygen -t rsa		
# Import the opposite host 
ssh-copy-id [email protected]
ssh-copy-id [email protected]

2.4 Set interactive and secret free login

vim /etc/ssh/ssh_config
35    StrictHostKeyChecking no

systemctl restart sshd

3、 ... and 、Ansible Command module

Command format : ansible < Group name > -m < modular > -a < parameter list >

ansible-doc -l			# Query all installed modules , Press q sign out 

There are more than 3000 modules , We only need to learn common

3.1 command modular

Execute command on remote host , Pipes are not supported , Redirect etc. shell Characteristics of .

ansible-doc -s command					#-s  List the description information and operation actions of the specified module 

ansible 192.168.109.131 -m command -a 'ifconfig'	# Appoint ip Carry out orders 
ansible webservers -m command -a 'free'				# Specify the group to execute the command 
ansible dbservers -m command -a 'free'
ansible all -m command -a 'date'					#all On behalf of all  hosts  host 
ansible all -a 'date'								# If omitted  -m  modular , It means the default  command  modular 

### Commonly used parameters 
chdir: Enter the directory in advance before running the command on the remote host 
creates: Determine whether the specified file exists , If there is , Do not perform the following operations 
removes: Determine whether the specified file exists , If there is , Perform subsequent operations 

3.1.1 Example ：chdir

[[email protected] opt]# ansible dbservers -m command -a 'chdir=/opt ls ./'
192.168.109.132 | CHANGED | rc=0 >>
rh

3.1.2 Example ：creates

# Determine whether the specified file exists , If there is , Do not perform the following operations 
[[email protected] opt]# ansible dbservers -m command -a 'creates=/opt/123.txt echo helloworld >/opt/123.txt '
192.168.109.132 | CHANGED | rc=0 >>
helloworld >/opt/123.txt

# Switch 132 Machine check 
[[email protected] opt]# ls
123.txt  rh

3.1.3 Example ：removes

# Determine whether the specified file exists , If there is , Perform subsequent operations 
[[email protected] opt]# ansible dbservers -m command -a 'removes=/opt/123.txt touch /opt/123.txt'
[WARNING]: Consider using the file module with state=touch rather than running 'touch'.  If you need to use command because file is insufficient you can add 'warn: false' to this command task or set 'command_warnings=False' in ansible.cfg to get rid of this message.
192.168.109.132 | CHANGED | rc=0 >>

[[email protected] opt]# ansible dbservers -m command -a 'removes=/opt/123.txt rm -f /opt/123.txt'
[WARNING]: Consider using the file module with state=absent rather than running 'rm'.  If you need to use command because file is insufficient you can add 'warn: false' to this command task or set 'command_warnings=False' in ansible.cfg to get rid of this message.
192.168.109.132 | CHANGED | rc=0 >>

[[email protected] opt]# ansible dbservers -m command -a 'removes=/opt/123.txt touch /opt/123.txt'
192.168.109.132 | SUCCESS | rc=0 >>
skipped, since /opt/123.txt does not exist

3.2 shell modular

Execute command on remote host , Equivalent to calling the shell process , Then in the shell Open next child shell Run the command ( Support functions such as pipe symbols )

ansible-doc -s shell
# write in helloworld To 123.txt
[[email protected] opt]# ansible dbservers -m shell -a 'echo helloworld >/opt/123.txt '
192.168.109.132 | CHANGED | rc=0 >>
# Filter IP Address 
[[email protected] opt]# ansible dbservers -m shell -a 'ifconfig ens33|awk "NR==2 {print \$2}"'
192.168.109.132 | CHANGED | rc=0 >>
192.168.109.132

3.3 cron modular

Define the task schedule on the remote host , There are two states （state）：present Express addition （ It can be omitted ）,absent Indicated removal .

ansible-doc -s cron					# View related instructions , Press q sign out 

 Common parameters ：
minute/hour/day/month/weekday: branch / when / Japan / month  / Zhou 
job: The command to be executed in the task plan 
name : Name of the task plan 

# Every two months 10 Copy the system kernel log to /opt/
linux：10 10,22 10 */2 * /usr/bin/cp  /var/log/messages /opt
ansible：
[[email protected] opt]# ansible dbservers -m cron -a 'minute="10" hour="10,20" day="10" month="*/2" job="/usr/bin/cp /var/log/messages /opt" name="test crontab"'
192.168.109.132 | CHANGED => {
    
    "ansible_facts": {
    
        "discovered_interpreter_python": "/usr/bin/python"
    }, 
    "changed": true, 
    "envs": [], 
    "jobs": [
        "test crontab"
    ]
}
# Check out the task list 
[[email protected] opt]# ansible dbservers -a 'crontab -l'
192.168.109.132 | CHANGED | rc=0 >>
#Ansible: test crontab
10 10,20 10 */2 * /usr/bin/cp  /var/log/messages /opt
[[email protected] opt]# 
# Switch to 132 Upload and view the machine 
[[email protected] opt]# crontab -l
#Ansible: test crontab
10 10,20 10 */2 * /usr/bin/cp  /var/log/messages /opt

3.4 user modular

User management module

ansible-doc -s user

 Common parameters ：
name : user name , Required parameters 
state=present|absent: Create account or delete account ,present Representation creation ,absent  Said to delete 
system=yes|no: Whether it is a system account 
uid:  user uid
group: User base group 
groups： Additional group 
shell: Default shell
move_home=yse|no: If the set home diary already exists , Whether to move the existing home diary 
password: User's password , It is recommended to use encrypted strings 
comment: User's comment information 
remove=yes|no: When state=absent when ,  Delete user's home directory 

ansible webservers -m user -a 'name="test001"'						# establish 
ansible webservers -m command -a 'tail -1 /etc/passwd'				# Check to confirm 
ansible webservers -m user -a 'name="test001" state=absent'			# Delete 
ansible webservers -m command -a 'tail -1 /etc/passwd'				# Check to confirm 

3.5 group modular

User group management module

ansible-doc -s group			# View related documents 

ansible dbservers -m group -a 'name=mysql gid=300 system=yes'
ansible dbservers -m command -a 'tail -1 /etc/group'
ansible dbservers -m user -a 'name="test002" uid=300 system=yes group=mysql'
ansible dbservers -m command -a 'tail -2 /etc/passwd'
ansible dbservers -a 'id test002'

3.6 copy modular

Used to copy the specified host file to the remote host

ansible-doc -s copy				# View related documents 

## Common parameters 
dest: Point out the date mark and location of the copied document , Using absolute paths , If it is the source directory , The target is also a directory , If the target file already exists, the original content will be overwritten 
src: Indicates the path to the source file , You can use relative or absolute paths , Direct directory assignment is supported , If the source is a directory, the target is also a directory 
mode: When indicating replication , Permissions of the target file 
owner: When indicating replication , Owner of the target file 
group: When indicating replication , The group to which the target file belongs 
content: Indicate what is copied to the target host , Cannot be associated with src Use it together 

## Test creating files and modifying permissions 
ansible dbservers -a 'mkdir /test'
ansible dbservers -m copy -a 'src=/etc/passwd dest=/test/passwd.bak owner=root mode=640'
ansible dbservers -a 'ls -l /test'

## Test create file and write content 
ansible dbservers -m copy -a 'content="this is test txt" dest=/test/test.txt'
ansible dbservers -a 'ls -l /test'
ansible dbservers -a 'cat /test/test.txt'

3.7 file modular

Set file properties

ansible-doc -s file

# Modify the permissions of the main group of the file 
ansible dbservers -m file -a 'owner=zhangsan group=mysql mode=777 path=/opt/123.txt'	
ansible dbservers -a 'ls -l /opt'

## Set up /opt/123.txt.bak  by  /opt/123.txt  Link file for 
ansible dbservers -m file -a 'path=/opt/123.txt.link src=/opt/123.txt state=link'

ansible dbservers -m file -a 'path=/opt/abc.txt state=touch'	# Create a file 
ansible dbservers -m file -a 'path=/opt/abc.txt state=absent'	# Delete a file 

3.7.1 Modify owner, group and permission

3.7.2 Create soft link

3.7.3 create a file , And delete the file

3.8 hostname modular

Used to manage host names on remote hosts

ansible dbservers -m hostname -a 'name=testhost'

3.9 ping modular

ansible all -m ping 

3.10 yum modular

Install and uninstall the software package on the remote host

ansible-doc -s yum

ansible webservers -m yum -a 'name=httpd'						# Installation services 
ansible webservers -m yum -a 'name=httpd state=absent'			# Uninstall service 

3.11 service/systemd modular

Used to manage the running state of the service on the remote host

ansible-doc -s service

## Common parameters 
name: Managed service name .
state=started | stopped | restarted: Actions include startup, shutdown or restart .
enabled=yes | no: Indicates whether to set the service to start automatically .
runlevel: If you set enabled Start and start automatically , Then you need to define the running targets under which to start automatically .

ansible webservers -m service -a 'name=httpd enabled=true state=started'		# Install the service and set it to start automatically 
systemctl is-enabled  httpd.service			# The controlled end checks whether it is set to start automatically 

3.12 script modular

Realize remote batch operation of local shell Script

ansible-doc -s script

vim test.sh						# Write a script 
#!/bin/bash
echo "hello ansible from script" > /opt/script.txt		# stay script.txt Write the specified content in 

chmod +x test.sh 										# To give permission 
ansible dbservers -m script -a 'test.sh'				# Realize remote running of local scripts 
ansible dbservers -a 'cat /opt/script.txt'				# View the generated document content 

3.13 setup modular

facts Component is used to collect information of managed nodes , Use setup The module can get this information

ansible-doc -s setup

ansible webservers -m setup							# obtain webservers Group host's facts Information 
ansible webservers -m setup -a 'filter=*ipv4'		# Use filter You can filter the specified facts Information