1.ansible介绍
ssh秘钥认证+脚本批量管理，特点：简单、实用，
但是看起来比较LOW，需要人工写脚本，类似实时复制的inotify工具。
2013以前这种方式很普遍。
MySQL高可用 MHA集群，要求所有机器互相秘钥认证。
大数据集群也需要。
2.ansible能做什么？
ansible可以帮助我们完成一些批量任务，或者完成一些需要经常重复的工作。
比如：同时在100台服务器上安装nfs服务，并在安装后启动服务。
比如：将某个文件一次性拷贝到100台服务器上。
比如：每当有新服务器加入工作环境时，你都要为新服务器部署某个服务，也就是说你需要经常重复的完成相同的工作。
这些场景中我们都可以使用到ansible。
3.ansible软件特点：
ansible可以帮助我们完成一些批量任务，或者完成一些需要经常重复的工作。
比如：同时在100台服务器上安装nfs服务，并在安装后启动服务。
比如：将某个文件一次性拷贝到100台服务器上。
比如：每当有新服务器加入工作环境时，你都要为新服务器部署某个服务，也就是说你需要经常重复的完成相同的工作。
这些场景中我们都可以使用到ansible。
4.安装ansible
[root@m01 ~]# yum install ansible -y.配置ansible[root@m01 ~]# vim /etc/ansible/hosts[oldboy]172.16.1.31
172.16.1.41
验证ansible
ansible是通过ssh端口探测通信
[root@m01 ~]# ansible oldboy -m ping
172.16.1.7 | SUCCESS =>{"changed": false,"ping":"pong"}172.16.1.31 | SUCCESS =>{"changed": false,"ping":"pong"}172.16.1.41 | SUCCESS =>{"changed": false,"ping":"pong"}
ansible命令参数介绍
Ansible中的临时命令的执行是通过Ad-Hoc来完成，能够快速执行，而且不需要保存执行的命令，例如：ansible -i ～/hosts all -mcommand-a ‘who’ -u root主要参数如下：-u username 指定ssh连接的用户名，即执行后面命令的用户-i inventory_file 指定所使用的inventory文件的位置，默认为/etc/ansible/hosts-m module 指定使用的模块，默认为command-f 10 指定并发数，并发量大的时候，提高该值--sudo [-k] 当需要root权限执行的化，-k参数用来输入root密码
ansible模块查看和帮助
ansible模块查看和帮助*****查找模块ansible-doc -l#模块就Linux命令了。查看某个模块的具体参数帮助ansible-doc -scommand#Linux命令参数12.1command模块 *****1）功能说明：commandExecutes acommandon a remote node 功能说明：执行一个命令在远程节点上操作实践：ansible oldboy -mcommand-a"free -m"ansible oldboy -mcommand-a"df -h"ansible oldboy -mcommand-a"ls /root"ansible oldboy -mcommand-a"cat redhat-release"ansible oldboy -mcommand-a"cat /etc/redhat-release"最通用的功能。[root@m01 ~]# ansible oldboy -m command -a "cat /etc/redhat-release"172.16.1.7 | CHANGED | rc=0 >>CentOS Linux release 7.6.1810 (Core) 172.16.1.31 | CHANGED | rc=0 >>CentOS Linux release 7.6.1810 (Core) 172.16.1.41 | CHANGED | rc=0 >>CentOS Linux release 7.6.1810 (Core)
目标：ansible是不是需要免秘钥认证(ssh免秘钥认证)？ yes
[root@m01 ~]# cat /etc/ansible/hosts[oldboy]172.16.1.31172.16.1.7还原ansible.cfg配置，重启服务器[root@m01 ~]# ansible oldboy -m command -a "free -m"The authenticity of host'172.16.1.7 (172.16.1.7)'can't be established.
ECDSA key fingerprint is SHA256:qZSBkrmOv7xO/63qOU1uLXkPyNVHdkqvrNAcAmXqNEk.
ECDSA key fingerprint is MD5:23:d0:cb:a9:f4:7c:0b:eb:2d:07:00:e1:a3:12:d8:33.
Are you sure you want to continue connecting (yes/no)? The authenticity of host '172.16.1.31(172.16.1.31)' can't be established.ECDSA key fingerprint isSHA256:qZSBkrmOv7xO/63qOU1uLXkPyNVHdkqvrNAcAmXqNEk.ECDSA key fingerprint isMD5:23:d0:cb:a9:f4:7c:0b:eb:2d:07:00:e1:a3:12:d8:33.Are you sure you want to continue connecting (yes/no)?
解决yes/no不需要输入问题：
修改ansible.cfg374行：ssh_args = -o ControlMaster=auto-o ControlPersist=60s -o StrictHostKeyChecking=no
在执行报错：
[root@m01 ~]# ansible oldboy -m command -a "free -m"172.16.1.7| UNREACHABLE! => {"changed":false,"msg":"Failed to connect to the host via ssh: Warning: Permanently added '172.16.1.7' (ECDSA) to the list of known hosts.\r\nPermission denied (publickey,password).","unreachable":true}172.16.1.31| UNREACHABLE! => {"changed":false,"msg":"Failed to connect to the host via ssh: Warning: Permanently added '172.16.1.31' (ECDSA) to the list of known hosts.\r\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic,password).","unreachable":true}
解决公钥问题：
ssh-keygen -f ~/.ssh/id_rsa -P''-qforipin7dosshpass -p123456 ssh-copy-id -f -i ~/.ssh/id_rsa.pub"-o StrictHostKeyChecking=no"172.16.1.$ipdone#testssh172.16.1.7"ifconfig eth0"
执行ansible命令：
[root@m01 ~]# ansible oldboy -m command -a "free -m"172.16.1.31 | UNREACHABLE! =>{"changed": false,"msg":"Failed to connect to the host via ssh: Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).","unreachable": true}172.16.1.7 | CHANGED | rc=0 >> total used free shared buff/cache availableMem:97269807795771Swap:7670767foripin31dosshpass -p123456 ssh-copy-id -f -i ~/.ssh/id_rsa.pub"-o StrictHostKeyChecking=no"172.16.1.$ipdone#testssh172.16.1.31"ifconfig eth0"[root@m01 ~]# ansible oldboy -m command -a "free -m"172.16.1.7 | CHANGED | rc=0 >> total used free shared buff/cache availableMem:97269807795771Swap:7670767172.16.1.31 | CHANGED | rc=0 >> total used free shared buff/cache availableMem:97271804796768Swap:7670767
验证：删除公钥，是不是不可以了？
重启后，不行，重启前可以[root@m01 ~]# ansible oldboy -m command -a "free -m"172.16.1.7| UNREACHABLE! => {"changed":false,"msg":"Failed to connect to the host via ssh: Warning: Permanently added '172.16.1.7' (ECDSA) to the list of known hosts.\r\nPermission denied (publickey,password).","unreachable":true}172.16.1.31| UNREACHABLE! => {"changed":false,"msg":"Failed to connect to the host via ssh: Could not create directory '/root/.ssh'.\r\nWarning: Permanently added '172.16.1.31' (ECDSA) to the list of known hosts.\r\nPermission denied (publickey,gssapi-keyex,gssapi-with-mic,password).","unreachable":true}
修改Host增加用户和密码：
[root@m01 ~]# cat /etc/ansible/hosts#[oldboy]#172.16.1.31#172.16.1.7[oldboy_pass]172.16.1.31 ansible_ssh_user=root ansible_ssh_pass=123456
172.16.1.7 ansible_ssh_user=root ansible_ssh_pass=123456
结果：
[root@m01 ~]# ansible oldboy_pass -m command -a "free -m"
172.16.1.31 | CHANGED | rc=0 >> total used free shared buff/cache availableMem:972797917101758Swap:7670767172.16.1.7 | CHANGED | rc=0 >> total used free shared buff/cache availableMem:97269806795771Swap:7670767