《Ansible自动化运维：技术与最佳实践》第二章读书笔记

川长思鸟来 2023-06-02 14:54 1阅读 0赞

# Ansible 安装与配置 #

本章主要讲的是 Ansible 安装与基本配置，主要包含以下内容：

1.  Ansible 环境准备
2.  安装 Ansible
3.  配置运行环境
4.  Ansible实践

## Ansible 环境准备 ##

从 GitHub 获取 Ansible，准备控制主机，查看被管节点。

使用的操作系统为 Centos 7.0，自带 Python 2.7.5。

<table> 
 <thead> 
  <tr> 
   <th>角色</th> 
   <th>主机名</th> 
   <th>IP 地址</th> 
   <th>组名</th> 
   <th>CPU</th> 
   <th>Web 根目录</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>被管节点</td> 
   <td>web1</td> 
   <td>192.168.46.128</td> 
   <td>webservers</td> 
   <td>2</td> 
   <td>/website</td> 
  </tr> 
  <tr> 
   <td>被管节点</td> 
   <td>web2</td> 
   <td>192.168.46.129</td> 
   <td>webservers</td> 
   <td>2</td> 
   <td>/website</td> 
  </tr> 
  <tr> 
   <td>控制节点</td> 
   <td>ansiblecontrol</td> 
   <td>192.168.46.130</td> 
   <td>---</td> 
   <td>---</td> 
   <td>---</td> 
  </tr> 
 </tbody> 
</table>

> 永久性的修改主机名称`hostnamectl set-hostname web1`

## 安装 Ansible ##

Ansible 的安装方式分为直接用源码安装以及用包管理工具安装。

### 直接用源码安装 ###

从 GitHub 源码库安装方式

提取 Ansible 源代码

git clone https://github.com/ansible/ansible.git -- recursive
    cd ./ansible
    # 减少告警/错误信息输出，可在安装时加上 -q 参数
    source ./hacking/env-setup -q

若没有安装 pip，安装对应 Python 版本的 pip

sudo easy_install pip

安装 Ansible 控制主机需要的 Python 模块

sudo pip install paramiko PyYAML Jinja2 httplib2 six

当更新 Ansible 版本时，要更新 git 源码树以及 git 中指向 Ansible 自身的模块（称为 submodules）

git pull --rebase
    git submodule update --init --recursive

运行 env-setup 脚本（默认资源清单 inventory 文件是 /etc/ansible/hosts）

.. code-block:: bash
    echo "127.0.0.1" > ~/ansible_hosts
    export ANSIBLE_HOSTS=~/ansible_hosts

> 通过 GitHub 仓库安装的，需要把仓库中 examples 目录下的 ansible.cfg 复制到 /etc/ansible 目录下

### 用包管理工具安装 ###

pip安装方式

#安装 pip
    sudo easy_install pip
    #通过 pip 命令安装 Ansible
    sudo pip install ansible

> 通过 pip 安装的，没有自动生成的配置文件，需要自己新建 /etc/ansible/ansible.cfg

## 配置运行环境 ##

配置文件优先级：

1.  ANSIBLE\_CONFIG：首先，Ansible 命令会检查环境变量，以及环境变量指向的配置文件。
2.  ./ansible.cfg：其次，会检查当前目录下的 ansible.cfg 配置文件。
3.  ~/ansible.cfg：再次，会检查当前用户 home 目录下的 ansible.cfg 配置文件。
4.  /etc/ansible/ansible.cfg：最后，会检查安装时自动生成的配置文件。

### 配置 Ansible 环境 ###

1.  使用环境变量方式配置
2.  设置 ansible.cfg 配置参数

[defaults]
    
    #inventory      = /etc/ansible/hosts    #inventory文件路径
    #library        = /usr/share/my_modules/    #模块文件路径
    #module_utils   = /usr/share/my_module_utils/   #自定义模块工具存放目录
    #remote_tmp     = ~/.ansible/tmp    #临时文件远程主机存放目录
    #local_tmp      = ~/.ansible/tmp    #临时文件本地存放目录
    #plugin_filters_cfg = /etc/ansible/plugin_filters.yml
    #forks          = 5 #默认开启的进程数
    #poll_interval  = 15    #默认轮询时间间隔
    #sudo_user      = root  #默认sudo用户
    #ask_sudo_pass = True   #是否需要sudo密码
    #ask_pass      = True   #是否需要密码
    #transport      = smart 通信机制，如果本地系统支持 ControlPersist技术的话,将会使用(基于OpenSSH)‘ssh’,如果不支持将使用‘paramiko’，其他传输选项‘local’,‘chroot’,’jail’等等
    #remote_port    = 22    #连接被管节点的管理端口
    #module_lang    = C #模块运行的语言环境
    #module_set_locale = False
    #gathering = implicit   #facts信息收集开关，implicit（默认不收集）
    #gather_subset = all    #facts 的收集范围
    # gather_timeout = 10   #收集超时间隔
    
    # Ansible facts are available inside the ansible_facts.* dictionary
    # namespace. This setting maintains the behaviour which was the default prior
    # to 2.5, duplicating these variables into the main namespace, each with a
    # prefix of 'ansible_'.
    # This variable is set to True by default for backwards compatibility. It
    # will be changed to a default of 'False' in a future release.
    # ansible_facts.
    # inject_facts_as_vars = True
    
    #roles_path    = /etc/ansible/roles #role存放路径
    
    #host_key_checking = False  #是否检查SSH主机的密钥
    
    # change the default callback, you can only have one 'stdout' type  enabled at a time.
    #stdout_callback = skippy
    
    # enable callback plugins, they can output to stdout but cannot be 'stdout' type.
    #callback_whitelist = timer, mail
    
    # Determine whether includes in tasks and handlers are "static" by
    # default. As of 2.0, includes are dynamic by default. Setting these
    # values to True will make includes behave more like they did in the
    # 1.x versions.
    #task_includes_static = False
    #handler_includes_static = False
    
    # Controls if a missing handler for a notification event is an error or a warning
    #error_on_missing_handler = True
    
    #sudo_exe = sudo    #ansible sudo执行命令
    #sudo_flags = -H -S -n  #ansible sudo执行参数
    #timeout = 10   #ansible SSH连接的超时间隔/秒
    #remote_user = root #ansible 远程认证用户
    #log_path = /var/log/ansible.log    #指定存储日志的文件
    #module_name = command  #ansible 默认执行模块
    
    #executable = /bin/sh   #ansible 命令执行 shell
    
    # if inventory variables overlap, does the higher precedence one win
    # or are hash values merged together?  The default is 'replace' but
    # this can also be set to 'merge'.
    #hash_behaviour = replace   #ansible 主机变量重复处理方式
    
    # by default, variables from roles will be visible in the global variable
    # scope. To prevent this, the following option can be enabled, and only
    # tasks and handlers within the role will see the variables there
    #private_role_vars = yes
    
    #jinja2_extensions = jinja2.ext.do,jinja2.ext.i18n  #Jinja2 扩展列表
    
    #private_key_file = /path/to/file   #ansible ssh 私钥文件
    
    # If set, configures the path to the Vault password file as an alternative to
    # specifying --vault-password-file on the command line.
    #vault_password_file = /path/to/vault_password_file
    
    
    #ansible_managed = Ansible managed: {file} modified on %Y-%m-%d %H:%M:%S by {uid} on {host} #在 jinja2 中格式化 ansible_managed 变量
    #ansible_managed = Ansible managed
    
    #display_skipped_hosts = True   #开启显示跳过的主机
    
    # by default, if a task in a playbook does not include a name: field then
    # ansible-playbook will construct a header that includes the task's action but
    # not the task's args.  This is a security feature because ansible cannot know
    # if the *module* considers an argument to be no_log at the time that the
    # header is printed.  If your environment doesn't have a problem securing
    # stdout from ansible-playbook (or you have manually specified no_log in your
    # playbook on all of the tasks where you have secret information) then you can
    # safely set this to True to get more informative messages.
    #display_args_to_stdout = False
    
    #error_on_undefined_vars = False    #开启错误，或者没有定义的变量
    
    #system_warnings = True #开启第三方包系统警告
    
    #deprecation_warnings = True    #配置是否显示弃用警告
    
    # (as of 1.8), Ansible can optionally warn when usage of the shell and
    # command module appear to be simplified by using a default Ansible module
    # instead.  These warnings can be silenced by adjusting the following
    # setting or adding warn=yes or warn=no to the end of the command line
    # parameter string.  This will for example suggest using the git module
    # instead of shelling out to the git command.
    # command_warnings = False
    
    
    # set plugin path directories here, separate with colons
    #action_plugins     = /usr/share/ansible/plugins/action #ansible action 插件路径
    #become_plugins     = /usr/share/ansible/plugins/become
    #cache_plugins      = /usr/share/ansible/plugins/cache
    #callback_plugins   = /usr/share/ansible/plugins/callback
    #connection_plugins = /usr/share/ansible/plugins/connection
    #lookup_plugins     = /usr/share/ansible/plugins/lookup
    #inventory_plugins  = /usr/share/ansible/plugins/inventory
    #vars_plugins       = /usr/share/ansible/plugins/vars
    #filter_plugins     = /usr/share/ansible/plugins/filter
    #test_plugins       = /usr/share/ansible/plugins/test
    #terminal_plugins   = /usr/share/ansible/plugins/terminal
    #strategy_plugins   = /usr/share/ansible/plugins/strategy
    
    
    # by default, ansible will use the 'linear' strategy but you may want to try
    # another one
    #strategy = free
    
    #bin_ansible_callbacks = False  #开启 ansible 命令加载 callback 插件
    
    #nocows = 1 #是否开启 ansiblenocows 图形
    
    # set which cowsay stencil you'd like to use by default. When set to 'random',
    # a random stencil will be selected for each task. The selection will be filtered
    # against the `cow_whitelist` option below.
    #cow_selection = default
    #cow_selection = random
    
    # when using the 'random' option for cowsay, stencils will be restricted to this list.
    # it should be formatted as a comma-separated list with no spaces between names.
    # NOTE: line continuations here are for formatting purposes only, as the INI parser
    #       in python does not support them.
    #cow_whitelist=bud-frogs,bunny,cheese,daemon,default,dragon,elephant-in-snake,elephant,eyes,\
    #              hellokitty,kitty,luke-koala,meow,milk,moofasa,moose,ren,sheep,small,stegosaurus,\
    #              stimpy,supermilker,three-eyes,turkey,turtle,tux,udder,vader-koala,vader,www
    
    #nocolor = 1    #是否开启 ansible 颜色输出
    
    # if set to a persistent type (not 'memory', for example 'redis') fact values
    # from previous runs in Ansible will be stored.  This may be useful when
    # wanting to use, for example, IP information from one group of servers
    # without having to talk to them in the same playbook run to get their
    # current IP information.
    #fact_caching = memory
    
    #This option tells Ansible where to cache facts. The value is plugin dependent.
    #For the jsonfile plugin, it should be a path to a local directory.
    #For the redis plugin, the value is a host:port:database triplet: fact_caching_connection = localhost:6379:0
    
    #fact_caching_connection=/tmp
    
    
    
    # retry files
    # When a playbook fails a .retry file can be created that will be placed in ~/
    # You can enable this feature by setting retry_files_enabled to True
    # and you can change the location of the files by setting retry_files_save_path
    
    #retry_files_enabled = False
    #retry_files_save_path = ~/.ansible-retry
    
    # squash actions
    # Ansible can optimise actions that call modules with list parameters
    # when looping. Instead of calling the module once per with_ item, the
    # module is called once with all items at once. Currently this only works
    # under limited circumstances, and only with parameters named 'name'.
    #squash_actions = apk,apt,dnf,homebrew,pacman,pkgng,yum,zypper
    
    # prevents logging of task data, off by default
    #no_log = False
    
    # prevents logging of tasks, but only on the targets, data is still logged on the master/controller
    #no_target_syslog = False
    
    # controls whether Ansible will raise an error or warning if a task has no
    # choice but to create world readable temporary files to execute a module on
    # the remote machine.  This option is False by default for security.  Users may
    # turn this on to have behaviour more like Ansible prior to 2.1.x.  See
    # https://docs.ansible.com/ansible/become.html#becoming-an-unprivileged-user
    # for more secure ways to fix this than enabling this option.
    #allow_world_readable_tmpfiles = False
    
    # controls the compression level of variables sent to
    # worker processes. At the default of 0, no compression
    # is used. This value must be an integer from 0 to 9.
    #var_compression_level = 9
    
    # controls what compression method is used for new-style ansible modules when
    # they are sent to the remote system.  The compression types depend on having
    # support compiled into both the controller's python and the client's python.
    # The names should match with the python Zipfile compression types:
    # * ZIP_STORED (no compression. available everywhere)
    # * ZIP_DEFLATED (uses zlib, the default)
    # These values may be set per host via the ansible_module_compression inventory
    # variable
    #module_compression = 'ZIP_DEFLATED'
    
    #max_diff_size = 1048576    #diff文件的大小限制/字节
    
    # This controls how ansible handles multiple --tags and --skip-tags arguments
    # on the CLI.  If this is True then multiple arguments are merged together.  If
    # it is False, then the last specified argument is used and the others are ignored.
    # This option will be removed in 2.8.
    #merge_multiple_cli_flags = True
    
    # Controls showing custom stats at the end, off by default
    #show_custom_stats = True
    
    # Controls which files to ignore when using a directory as inventory with
    # possibly multiple sources (both static and dynamic)
    #inventory_ignore_extensions = ~, .orig, .bak, .ini, .cfg, .retry, .pyc, .pyo
    
    # This family of modules use an alternative execution path optimized for network appliances
    # only update this setting if you know how this works, otherwise it can break module execution
    #network_group_modules=eos, nxos, ios, iosxr, junos, vyos
    
    # When enabled, this option allows lookups (via variables like {
        {lookup('foo')}} or when used as
    # a loop with `with_foo`) to return data that is not marked "unsafe". This means the data may contain
    # jinja2 templating language which will be run through the templating engine.
    # ENABLING THIS COULD BE A SECURITY RISK
    #allow_unsafe_lookups = False
    
    # set default errors for all plays
    #any_errors_fatal = False
    
    [inventory]
    # enable inventory plugins, default: 'host_list', 'script', 'auto', 'yaml', 'ini', 'toml'
    #enable_plugins = host_list, virtualbox, yaml, constructed
    
    # ignore these extensions when parsing a directory as inventory source
    #ignore_extensions = .pyc, .pyo, .swp, .bak, ~, .rpm, .md, .txt, ~, .orig, .ini, .cfg, .retry
    
    # ignore files matching these patterns when parsing a directory as inventory source
    #ignore_patterns=
    
    # If 'true' unparsed inventory sources become fatal errors, they are warnings otherwise.
    #unparsed_is_failed=False
    
    [privilege_escalation]
    #become=True    #是否开启 become 模式
    #become_method=sudo #定义 become 方式
    #become_user=root   #定义 become 用户
    #become_ask_pass=False  #是否定义 become 提示密码
    
    [paramiko_connection]
    
    #record_host_keys=False #是否记录主机 key
    
    #pty=False  #是否开启命令执行伪终端
    
    # paramiko will default to looking for SSH keys initially when trying to
    # authenticate to remote devices.  This is a problem for some network devices
    # that close the connection after a key failure.  Uncomment this line to
    # disable the Paramiko look for keys function
    #look_for_keys = False
    
    # When using persistent connections with Paramiko, the connection runs in a
    # background process.  If the host doesn't already have a valid SSH key, by
    # default Ansible will prompt to add the host key.  This will cause connections
    # running in background processes to fail.  Uncomment this line to have
    # Paramiko automatically add host keys.
    #host_key_auto_add = True
    
    [ssh_connection]
    #SSH 连接配置
    #ssh_args = -C -o ControlMaster=auto -o ControlPersist=60s  #ansib ssh参数，ControlMaster用于设置是否启用 SSH的Multiplexing，关闭则写no，ControlPersist为SSH session保持的时间
    
    # control_path_dir = /tmp/.ansible/cp   #ansible ssh 长连接控制文件
    #control_path_dir = ~/.ansible/cp
    
    # The path to use for the ControlPath sockets. This defaults to a hashed string of the hostname,
    # port and username (empty string in the config). The hash mitigates a common problem users
    # found with long hostnames and the conventional %(directory)s/ansible-ssh-%%h-%%p-%%r format.
    # In those cases, a "too long for Unix domain socket" ssh error would occur.
    #
    # Example:
    # control_path = %(directory)s/%%h-%%r
    #control_path =
    
    #pipelining = False #是否开启 pipelining 模式
    
    #scp_if_ssh = smart #是否开启scp模式推送脚本，smart（先尝试sftp推送，再尝试scp推送）
    
    # Control the mechanism for transferring files (new)
    # If set, this will override the scp_if_ssh option
    #   * sftp  = use sftp to transfer files
    #   * scp   = use scp to transfer files
    #   * piped = use 'dd' over SSH to transfer files
    #   * smart = try sftp, scp, and piped, in that order [default]
    #transfer_method = smart
    
    # if False, sftp will not use batch mode to transfer files. This may cause some
    # types of file transfer failures impossible to catch however, and should
    # only be disabled if your sftp version has problems with batch mode
    #sftp_batch_mode = False
    
    # The -tt argument is passed to ssh when pipelining is not enabled because sudo 
    # requires a tty by default. 
    #usetty = True
    
    #retries = 3    #重试与主机SSH连接的次数
    
    [persistent_connection]
    #持久连接配置
    #connect_timeout = 30   #持久连接超时间隔
    
    # The command timeout value defines the amount of time to wait for a command
    # or RPC call before timing out. The value for the command timeout must
    # be less than the value of the persistent connection idle timeout (connect_timeout)
    # The default value is 30 second.
    #command_timeout = 30
    
    [accelerate]
    #accelerate_port = 5099 #accelerate 远程监听端口
    #accelerate_timeout = 30    #accelerate 模式，命令执行超时时间/秒
    #accelerate_connect_timeout = 5.0   #accelerate 模式，连接超时时间/秒
    
    # The daemon timeout is measured in minutes. This time is measured
    # from the last activity to the accelerate daemon.
    #accelerate_daemon_timeout = 30
    
    # If set to yes, accelerate_multi_key will allow multiple
    # private keys to be uploaded to it, though each user must
    # have access to the system via SSH to add a new key. The default
    # is "no".
    #accelerate_multi_key = yes
    
    [selinux]
    #上下文配置
    #special_context_filesystems=nfs,vboxsf,fuse,ramfs,9p,vfat
    #libvirt_lxc_noseclabel = yes
    
    [colors]
    #highlight = white
    #verbose = blue
    #warn = bright purple
    #error = red
    #debug = dark gray
    #deprecate = purple
    #skip = cyan
    #unreachable = red
    #ok = green
    #changed = yellow
    #diff_add = green
    #diff_remove = red
    #diff_lines = cyan
    
    
    [diff]
    # always = no   #是否一直打印diff
    # context = 3   #diff中显示的上下文行数

### 配置 Linux 主机 SSH 无密码访问 ###

为避免 Ansible 下发指令时需要输入目标主机密码，通过证书签名达到 SSH 无密码访问。使用 ssh-keygen 和 ssh-copy-id 来实现快速证书的生成及公钥的下发。

在控制主机上创建密钥，执行`ssh-keygen -t rsa`，将在 /root/.ssh/ 下生成密钥，其中 id\_rsa 为私钥， id\_rsa.pub 为公钥。

#生成密钥
    ssh-keygen  -t rsa

下发密钥就是控制主机将公钥 is\_rsa.pub 下发到被管节点上用户下的 .ssh 目录，并重命名为 authorized\_keys，且权限值为400。

#下发公钥到 web1（192.168.46.128）
    ssh-copy-id -i id_rsa root@192.168.46.128
    #ssh连接验证
    ssh root@192.168.46.128
    #退出
    exit

## Ansible 实践 ##

### 主机连通性测试 ###

修改主机与组配置 /etc/ansible/hosts ，添加两台主机的ip地址，同时定义一个 webservers 组包含这两个地址

192.168.46.128
    192.168.46.129
    
    [webservers]
    192.168.46.128
    192.168.46.129

用 ping 模块对单台主机进行 ping 操作  
`ansible 192.168.46.128 -m ping`

结果如下

192.168.46.128 | SUCCESS => {
        "ansible_facts": {
            "discovered_interpreter_python": "/usr/bin/python"
        }, 
        "changed": false, 
        "ping": "pong"
    }

对 webservers 组进行 ping 操作  
`ansible webservers -m ping`

> 在命令后加 -v 或 -vvv 可得到详细的输出结果

结果如下

192.168.46.128 | SUCCESS => {
        "ansible_facts": {
            "discovered_interpreter_python": "/usr/bin/python"
        }, 
        "changed": false, 
        "ping": "pong"
    }
    192.168.46.129 | SUCCESS => {
        "ansible_facts": {
            "discovered_interpreter_python": "/usr/bin/python"
        }, 
        "changed": false, 
        "ping": "pong"
    }

### 在被管节点上批量执行命令 ###

在 home 目录下创建资源清单文件 inventory.cfg

`vim inventory.cfg`

内容如下：

[webservers]
    192.168.46.128
    192.168.46.129

用 Ansible 的 shell 模块 在 webservers 组的服务器上显示 hello ansible（用 common 模块也可以实现）

`ansible webservers -m shell -a '/bin/echo hello ansible' -i inventory.cfg`

结果如下：

192.168.46.128 | CHANGED | rc=0 >>
    hello ansible
    
    192.168.46.129 | CHANGED | rc=0 >>
    hello ansible

### Ansible 获取帮助信息 ###

`ansible-doc -h` 获得帮助

`ansible-doc -l` 获得工具下可使用的模块