1 - 配置管理工具
配置管理工具（SCM，Software Configuration Management）可以将代码、软件方式实现的基础设施配置信息保存，也可以根据需求变化反复进行变更。
相关工具包括Ansible、Chef、Puppet、SaltStack等，版本管理工具有Git、Subversion等。
配置管理工具的特征
- 声明式：通过配置信息对当前配置对象的具体状态进行明确描述，并管理这个状态；形式简单、易于理解；
- 抽象化：配置信息能涵盖细微的环境差异，不需要根据配置对象所在环境的细微差别而分开编写配置信息，消除代码执行时的特殊性；
- 收敛性：不管对象的状态如何，最终都会变为指定的期望状态
- 幂等性：无论执行多少次都能得到相同的结果
- 省时省力：配置信息轻量，易于传输，可以提高审查速度，能够快速回滚到上一个版本；开源；可通过自动化进行快速设置；
2 - Ansible简介
Ansible是基于python语言开发的一种开源的自动化运维工具和平台，集合了众多运维工具的优点，实现了批量配置管理、批量应用部署和运行命令执行特定任务等功能。
Ansible基于SSH来和远程主机通讯，不需要在远程主机上安装client/agents。
配置信息语法规则简单，命令简洁，容易入门。
Ansible只是提供一种框架，本身没有批量部署的能力。真正具有批量部署的是ansible所运行的模块。主要包括：
- 连接插件connection plugins：负责和被监控端实现通信
- host inventory：指定操作的主机，是一个配置文件里面定义监控的主机
- 各种模块核心模块、command模块、自定义模块
- 借助于插件完成记录日志邮件等功能
- playbook：剧本执行多个任务时，非必需可以让节点一次性运行多个任务
- 具备管理Docker容器的功能
Ansible官网与教程
- HomePage：https://www.ansible.com/
- Ansible中文权威指南：http://ansible.com.cn/
- Ansible自动化运维教程：https://www.w3cschool.cn/automate_with_ansible/
3 - Ansible安装
操作简单，例如在CentOS7中安装Ansible只需执行yum -y install epel-release和yum -y install ansible就可以。
3.1 Ansible命令参数
[root@localhost ~]# ansible
usage: ansible [-h] [--version] [-v] [-b] [--become-method BECOME_METHOD]
[--become-user BECOME_USER] [-K] [-i INVENTORY] [--list-hosts]
[-l SUBSET] [-P POLL_INTERVAL] [-B SECONDS] [-o] [-t TREE] [-k]
[--private-key PRIVATE_KEY_FILE] [-u REMOTE_USER]
[-c CONNECTION] [-T TIMEOUT]
[--ssh-common-args SSH_COMMON_ARGS]
[--sftp-extra-args SFTP_EXTRA_ARGS]
[--scp-extra-args SCP_EXTRA_ARGS]
[--ssh-extra-args SSH_EXTRA_ARGS] [-C] [--syntax-check] [-D]
[-e EXTRA_VARS] [--vault-id VAULT_IDS]
[--ask-vault-pass | --vault-password-file VAULT_PASSWORD_FILES]
[-f FORKS] [-M MODULE_PATH] [--playbook-dir BASEDIR]
[-a MODULE_ARGS] [-m MODULE_NAME]
pattern
ansible: error: too few arguments
[root@localhost ~]#
[root@localhost ~]# ansible --version
ansible 2.9.0
config file = /etc/ansible/ansible.cfg
configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
ansible python module location = /usr/lib/python2.7/site-packages/ansible
executable location = /bin/ansible
python version = 2.7.5 (default, Apr 11 2018, 07:36:10) [GCC 4.8.5 20150623 (Red Hat 4.8.5-28)]
[root@localhost ~]#
[root@localhost ~]# ll /etc/ansible/
total 24
-rw-r--r-- 1 root root 19985 Nov 9 05:11 ansible.cfg
-rw-r--r-- 1 root root 1016 Nov 9 05:11 hosts
drwxr-xr-x 2 root root 6 Nov 9 05:11 roles
[root@localhost ~]#
3.2 Inventory文件
默认是“/etc/ansible/hosts文件，定义了Ansible进行远程控制的对象服务器列表。
也可以在运行时使用-i参数指定其他文件作为Inventory文件。
[root@localhost ~]# sh -c "echo "localhost" >> /etc/ansible/hosts"
4 Ansible示例
4.1 安装并启动Nginx
# yum -y install epel-release
# yum -y install nginx
# echo "hello, Nginx" > /usr/share/nginx/html/index.html
# systemctl start nginx
[root@localhost ~]# systemctl status nginx.service
● nginx.service - The nginx HTTP and reverse proxy server
Loaded: loaded (/usr/lib/systemd/system/nginx.service; disabled; vendor preset: disabled)
Active: active (running) since Tue 2019-11-19 16:54:56 CST; 7min ago
Process: 6752 ExecStart=/usr/sbin/nginx (code=exited, status=0/SUCCESS)
Process: 6749 ExecStartPre=/usr/sbin/nginx -t (code=exited, status=0/SUCCESS)
Process: 6747 ExecStartPre=/usr/bin/rm -f /run/nginx.pid (code=exited, status=0/SUCCESS)
Main PID: 6754 (nginx)
Tasks: 3
CGroup: /system.slice/nginx.service
├─6754 nginx: master process /usr/sbin/nginx
├─6755 nginx: worker process
└─6756 nginx: worker process
Nov 19 16:54:56 localhost.localdomain systemd[1]: Starting The nginx HTTP and reverse proxy server...
Nov 19 16:54:56 localhost.localdomain nginx[6749]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
Nov 19 16:54:56 localhost.localdomain nginx[6749]: nginx: configuration file /etc/nginx/nginx.conf test is su...sful
Nov 19 16:54:56 localhost.localdomain systemd[1]: Started The nginx HTTP and reverse proxy server.
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost ~]#
[root@localhost ~]# curl http://192.168.16.101
hello, Nginx
4.2示例 - 启动已经运行的Nginx服务
[root@localhost ~]# ansible localhost -b -c local -m service -a "name=nginx state=started"
localhost | SUCCESS => {
"ansible_facts": {
"discovered_interpreter_python": "/usr/bin/python"
},
"changed": false,
"name": "nginx",
"state": "started",
"status": {
"ActiveEnterTimestamp": "Tue 2019-11-19 17:08:33 CST",
"ActiveEnterTimestampMonotonic": "8773946590",
"ActiveExitTimestampMonotonic": "0",
"ActiveState": "active",
......
......
......
"WatchdogTimestamp": "Tue 2019-11-19 16:54:56 CST",
"WatchdogTimestampMonotonic": "7957241107",
"WatchdogUSec": "0"
}
}
[root@localhost ~]#
4.3示例 - 启动并未运行的Nginx服务
[root@localhost ~]# systemctl stop nginx.service
[root@localhost ~]#
[root@localhost ~]# ansible localhost -b -c local -m service -a "name=nginx state=started"
localhost | CHANGED => {
"ansible_facts": {
"discovered_interpreter_python": "/usr/bin/python"
},
"changed": true,
"name": "nginx",
"state": "started",
"status": {
"ActiveEnterTimestampMonotonic": "0",
"ActiveExitTimestampMonotonic": "0",
"ActiveState": "inactive",
......
......
......
"WatchdogTimestampMonotonic": "0",
"WatchdogUSec": "0"
}
}
[root@localhost ~]#
5 - ansible-playbook
5.1 ansible-playbook简介
使用ansible-playbook命令能够以分组的方式处理或者操作对象，执行从安装、配置到启动等一系列操作。
这一系列操作（构建信息）必须提前定义在playbook文件中，然后通过指定playbook文件自动开始执行构建。
- playbook文件（YAML格式，后缀名为.yml）指定角色（roles）
- roles目录中的tasks具体定义一系列操作
- group_vars目录和roles下中templates目录为不同的环境设置变量值
ansible-playbook命令参数
[root@localhost ~]# ansible-playbook -h
usage: ansible-playbook [-h] [--version] [-v] [-k]
[--private-key PRIVATE_KEY_FILE] [-u REMOTE_USER]
[-c CONNECTION] [-T TIMEOUT]
[--ssh-common-args SSH_COMMON_ARGS]
[--sftp-extra-args SFTP_EXTRA_ARGS]
[--scp-extra-args SCP_EXTRA_ARGS]
[--ssh-extra-args SSH_EXTRA_ARGS] [--force-handlers]
[--flush-cache] [-b] [--become-method BECOME_METHOD]
[--become-user BECOME_USER] [-K] [-t TAGS]
[--skip-tags SKIP_TAGS] [-C] [--syntax-check] [-D]
[-i INVENTORY] [--list-hosts] [-l SUBSET]
[-e EXTRA_VARS] [--vault-id VAULT_IDS]
[--ask-vault-pass | --vault-password-file VAULT_PASSWORD_FILES]
[-f FORKS] [-M MODULE_PATH] [--list-tasks]
[--list-tags] [--step] [--start-at-task START_AT_TASK]
playbook [playbook ...]
Runs Ansible playbooks, executing the defined tasks on the targeted hosts.
positional arguments:
playbook Playbook(s)
optional arguments:
--ask-vault-pass ask for vault password
--flush-cache clear the fact cache for every host in inventory
--force-handlers run handlers even if a task fails
--list-hosts outputs a list of matching hosts; does not execute
anything else
--list-tags list all available tags
--list-tasks list all tasks that would be executed
--skip-tags SKIP_TAGS
only run plays and tasks whose tags do not match these
values
--start-at-task START_AT_TASK
start the playbook at the task matching this name
--step one-step-at-a-time: confirm each task before running
--syntax-check perform a syntax check on the playbook, but do not
execute it
--vault-id VAULT_IDS the vault identity to use
--vault-password-file VAULT_PASSWORD_FILES
vault password file
--version show program's version number, config file location,
configured module search path, module location,
executable location and exit
-C, --check don't make any changes; instead, try to predict some
of the changes that may occur
-D, --diff when changing (small) files and templates, show the
differences in those files; works great with --check
-M MODULE_PATH, --module-path MODULE_PATH
prepend colon-separated path(s) to module library (def
ault=~/.ansible/plugins/modules:/usr/share/ansible/plu
gins/modules)
-e EXTRA_VARS, --extra-vars EXTRA_VARS
set additional variables as key=value or YAML/JSON, if
filename prepend with @
-f FORKS, --forks FORKS
specify number of parallel processes to use
(default=5)
-h, --help show this help message and exit
-i INVENTORY, --inventory INVENTORY, --inventory-file INVENTORY
specify inventory host path or comma separated host
list. --inventory-file is deprecated
-l SUBSET, --limit SUBSET
further limit selected hosts to an additional pattern
-t TAGS, --tags TAGS only run plays and tasks tagged with these values
-v, --verbose verbose mode (-vvv for more, -vvvv to enable
connection debugging)
Connection Options:
control as whom and how to connect to hosts
--private-key PRIVATE_KEY_FILE, --key-file PRIVATE_KEY_FILE
use this file to authenticate the connection
--scp-extra-args SCP_EXTRA_ARGS
specify extra arguments to pass to scp only (e.g. -l)
--sftp-extra-args SFTP_EXTRA_ARGS
specify extra arguments to pass to sftp only (e.g. -f,
-l)
--ssh-common-args SSH_COMMON_ARGS
specify common arguments to pass to sftp/scp/ssh (e.g.
ProxyCommand)
--ssh-extra-args SSH_EXTRA_ARGS
specify extra arguments to pass to ssh only (e.g. -R)
-T TIMEOUT, --timeout TIMEOUT
override the connection timeout in seconds
(default=10)
-c CONNECTION, --connection CONNECTION
connection type to use (default=smart)
-k, --ask-pass ask for connection password
-u REMOTE_USER, --user REMOTE_USER
connect as this user (default=None)
Privilege Escalation Options:
control how and which user you become as on target hosts
--become-method BECOME_METHOD
privilege escalation method to use (default=sudo), use
`ansible-doc -t become -l` to list valid choices.
--become-user BECOME_USER
run operations as this user (default=root)
-K, --ask-become-pass
ask for privilege escalation password
-b, --become run operations with become (does not imply password
prompting)
[root@localhost ~]#
dry-run模式
用于预先验证要做的更改操作是否和预期一致。
在此模式下，Ansible不会真正在实际环境中执行更改操作，而是事先显示在实际执行时那些内容会被更改。
具体使用方法就是同时使用“--check”和“--diff”选项，表示以dry-run模式运行并显示详细的变更内容。
5.2 示例文件
下载地址：https://github.com/devops-book/ansible-playbook-sample
[root@localhost ansible-playbook-sample]# ll
total 12
-rw-r--r-- 1 root root 81 Nov 19 17:25 development
drwxr-xr-x 2 root root 73 Nov 19 17:25 group_vars
-rw-r--r-- 1 root root 79 Nov 19 17:25 production
drwxr-xr-x 7 root root 91 Nov 19 17:25 roles
-rw-r--r-- 1 root root 150 Nov 19 17:25 site.yml
[root@localhost ansible-playbook-sample]#
[root@localhost ansible-playbook-sample]# cat site.yml
---
- hosts: webservers
become: yes
connection: local
roles:
- common
- nginx
# - serverspec
# - serverspec_sample
# - jenkins
[root@localhost ansible-playbook-sample]#
[root@localhost ansible-playbook-sample]# tree
.
├── development
├── group_vars
│ ├── development-webservers.yml
│ └── production-webservers.yml
├── production
├── roles
│ ├── common
│ │ ├── meta
│ │ │ └── main.yml
│ │ └── tasks
│ │ └── main.yml
│ ├── jenkins
│ │ ├── defaults
│ │ │ └── main.yml
│ │ ├── handlers
│ │ │ └── main.yml
│ │ ├── meta
│ │ │ └── main.yml
│ │ ├── README.md
│ │ ├── tasks
│ │ │ └── main.yml
│ │ ├── tests
│ │ │ ├── inventory
│ │ │ └── test.yml
│ │ └── vars
│ │ └── main.yml
│ ├── nginx
│ │ ├── meta
│ │ │ └── main.yml
│ │ ├── tasks
│ │ │ └── main.yml
│ │ └── templates
│ │ └── index.html.j2
│ ├── serverspec
│ │ ├── meta
│ │ │ └── main.yml
│ │ └── tasks
│ │ └── main.yml
│ └── serverspec_sample
│ ├── files
│ │ └── serverspec_sample
│ │ ├── Rakefile
│ │ └── spec
│ │ ├── localhost
│ │ └── spec_helper.rb
│ ├── meta
│ │ └── main.yml
│ ├── tasks
│ │ └── main.yml
│ ├── templates
│ │ ├── nginx_spec.rb.j2
│ │ └── web_spec.rb.j2
│ └── vars
│ └── main.yml
└── site.yml
28 directories, 27 files
[root@localhost ansible-playbook-sample]#
5.3 示例 - 构建development环境
[root@localhost ansible-playbook-sample]# cat development
[development-webservers]
localhost
[webservers:children]
development-webservers
[root@localhost ansible-playbook-sample]#
[root@localhost ansible-playbook-sample]# ansible-playbook -i development site.yml
PLAY [webservers] **************************************************************************************************
TASK [Gathering Facts] *********************************************************************************************
ok: [localhost]
TASK [common : install epel] ***************************************************************************************
ok: [localhost]
TASK [nginx : install nginx] ***************************************************************************************
ok: [localhost]
TASK [nginx : replace index.html] **********************************************************************************
changed: [localhost]
TASK [nginx : nginx start] *****************************************************************************************
changed: [localhost]
PLAY RECAP *********************************************************************************************************
localhost : ok=5 changed=2 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
[root@localhost ansible-playbook-sample]#
[root@localhost ansible-playbook-sample]# curl localhost
hello, development ansible
[root@localhost ansible-playbook-sample]# curl 192.168.16.101
hello, development ansible
[root@localhost ansible-playbook-sample]#
5.4示例 - 构建product环境
[root@localhost ansible-playbook-sample]# cat production
[production-webservers]
localhost
[webservers:children]
production-webservers
[root@localhost ansible-playbook-sample]#
[root@localhost ansible-playbook-sample]# ansible-playbook -i production site.yml
PLAY [webservers] *****************************************************************************************
TASK [Gathering Facts] ************************************************************************************
ok: [localhost]
TASK [common : install epel] ******************************************************************************
ok: [localhost]
TASK [nginx : install nginx] ******************************************************************************
ok: [localhost]
TASK [nginx : replace index.html] *************************************************************************
changed: [localhost]
TASK [nginx : nginx start] ********************************************************************************
ok: [localhost]
PLAY RECAP *********************************************************************************************************************************************************************************************************************************
localhost : ok=5 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
[root@localhost ansible-playbook-sample]#
root@localhost ansible-playbook-sample]# curl 192.168.16.101
hello, production ansible
[root@localhost ansible-playbook-sample]#
6 - Ansible进阶
- 常用模块：Ansible功能的实现依赖于具体的模块
- Tag：只执行指定的任务
- Dynamic Inventory：从外部动态获取Inventory（主机列表）
- Ansible Galaxy：从网络获取使用roles并使用
- Ansible Tower：基于web的仪表板以及通过REST API对Ansible操作
7 - References
- ansible详解（一）：https://www.cnblogs.com/keerya/p/7987886.html
- ansible详解（二）：https://www.cnblogs.com/keerya/p/8004566.html
- Ansible之基础：https://www.jianshu.com/p/f751785bc71c
- Ansible之ansible-playbook：https://www.jianshu.com/p/171578692c94
- Ansible进阶技巧：https://www.ibm.com/developerworks/cn/linux/1608_lih_ansible/index.html