facts
Facts通过访问远程系统获取相应的信息。
一个例子就是远程主机的IP地址或者操作系统是什么. 使用以下命令可以查看哪些信息是可用的:
ansible hostname -m setup
这会返回巨量的变量数据,比如对于Ubutu 12.04系统，Ansible 1.4获取的信息显示如下:
"ansible_all_ipv4_addresses": [
"REDACTED IP ADDRESS"
],
"ansible_all_ipv6_addresses": [
"REDACTED IPV6 ADDRESS"
],
"ansible_architecture": "x86_64",
"ansible_bios_date": "09/20/2012",
"ansible_bios_version": "6.00",
"ansible_cmdline": {
"BOOT_IMAGE": "/boot/vmlinuz-3.5.0-23-generic",
"quiet": true,
"ro": true,
"root": "UUID=4195bff4-e157-4e41-8701-e93f0aec9e22",
"splash": true
},
"ansible_date_time": {
"date": "2013-10-02",
"day": "02",
"epoch": "1380756810",
"hour": "19",
"iso8601": "2013-10-02T23:33:30Z",
"iso8601_micro": "2013-10-02T23:33:30.036070Z",
"minute": "33",
"month": "10",
"second": "30",
"time": "19:33:30",
"tz": "EDT",
"year": "2013"
},
"ansible_default_ipv4": {
"address": "REDACTED",
"alias": "eth0",
"gateway": "REDACTED",
"interface": "eth0",
"macaddress": "REDACTED",
"mtu": 1500,
"netmask": "255.255.255.0",
"network": "REDACTED",
"type": "ether"
},
"ansible_default_ipv6": {},
"ansible_devices": {
"fd0": {
"holders": [],
"host": "",
"model": null,
"partitions": {},
"removable": "1",
"rotational": "1",
"scheduler_mode": "deadline",
"sectors": "0",
"sectorsize": "512",
"size": "0.00 Bytes",
"support_discard": "0",
"vendor": null
},
"sda": {
"holders": [],
"host": "SCSI storage controller: LSI Logic / Symbios Logic 53c1030 PCI-X Fusion-MPT Dual Ultra320 SCSI (rev 01)",
"model": "VMware Virtual S",
"partitions": {
"sda1": {
"sectors": "39843840",
"sectorsize": 512,
"size": "19.00 GB",
"start": "2048"
},
"sda2": {
"sectors": "2",
"sectorsize": 512,
"size": "1.00 KB",
"start": "39847934"
},
"sda5": {
"sectors": "2093056",
"sectorsize": 512,
"size": "1022.00 MB",
"start": "39847936"
}
},
"removable": "0",
"rotational": "1",
"scheduler_mode": "deadline",
"sectors": "41943040",
"sectorsize": "512",
"size": "20.00 GB",
"support_discard": "0",
"vendor": "VMware,"
},
"sr0": {
"holders": [],
"host": "IDE interface: Intel Corporation 82371AB/EB/MB PIIX4 IDE (rev 01)",
"model": "VMware IDE CDR10",
"partitions": {},
"removable": "1",
"rotational": "1",
"scheduler_mode": "deadline",
"sectors": "2097151",
"sectorsize": "512",
"size": "1024.00 MB",
"support_discard": "0",
"vendor": "NECVMWar"
}
},
"ansible_distribution": "Ubuntu",
"ansible_distribution_release": "precise",
"ansible_distribution_version": "12.04",
"ansible_domain": "",
"ansible_env": {
"COLORTERM": "gnome-terminal",
"DISPLAY": ":0",
"HOME": "/home/mdehaan",
"LANG": "C",
"LESSCLOSE": "/usr/bin/lesspipe %s %s",
"LESSOPEN": "| /usr/bin/lesspipe %s",
"LOGNAME": "root",
"LS_COLORS": "rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lz=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.axv=01;35:*.anx=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.axa=00;36:*.oga=00;36:*.spx=00;36:*.xspf=00;36:",
"MAIL": "/var/mail/root",
"OLDPWD": "/root/ansible/docsite",
"PATH": "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"PWD": "/root/ansible",
"SHELL": "/bin/bash",
"SHLVL": "1",
"SUDO_COMMAND": "/bin/bash",
"SUDO_GID": "1000",
"SUDO_UID": "1000",
"SUDO_USER": "mdehaan",
"TERM": "xterm",
"USER": "root",
"USERNAME": "root",
"XAUTHORITY": "/home/mdehaan/.Xauthority",
"_": "/usr/local/bin/ansible"
},
"ansible_eth0": {
"active": true,
"device": "eth0",
"ipv4": {
"address": "REDACTED",
"netmask": "255.255.255.0",
"network": "REDACTED"
},
"ipv6": [
{
"address": "REDACTED",
"prefix": "64",
"scope": "link"
}
],
"macaddress": "REDACTED",
"module": "e1000",
"mtu": 1500,
"type": "ether"
},
"ansible_form_factor": "Other",
"ansible_fqdn": "ubuntu2.example.com",
"ansible_hostname": "ubuntu2",
"ansible_interfaces": [
"lo",
"eth0"
],
"ansible_kernel": "3.5.0-23-generic",
"ansible_lo": {
"active": true,
"device": "lo",
"ipv4": {
"address": "127.0.0.1",
"netmask": "255.0.0.0",
"network": "127.0.0.0"
},
"ipv6": [
{
"address": "::1",
"prefix": "128",
"scope": "host"
}
],
"mtu": 16436,
"type": "loopback"
},
"ansible_lsb": {
"codename": "precise",
"description": "Ubuntu 12.04.2 LTS",
"id": "Ubuntu",
"major_release": "12",
"release": "12.04"
},
"ansible_machine": "x86_64",
"ansible_memfree_mb": 74,
"ansible_memtotal_mb": 991,
"ansible_mounts": [
{
"device": "/dev/sda1",
"fstype": "ext4",
"mount": "/",
"options": "rw,errors=remount-ro",
"size_available": 15032406016,
"size_total": 20079898624
}
],
"ansible_nodename": "ubuntu2.example.com",
"ansible_os_family": "Debian",
"ansible_pkg_mgr": "apt",
"ansible_processor": [
"Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz"
],
"ansible_processor_cores": 1,
"ansible_processor_count": 1,
"ansible_processor_threads_per_core": 1,
"ansible_processor_vcpus": 1,
"ansible_product_name": "VMware Virtual Platform",
"ansible_product_serial": "REDACTED",
"ansible_product_uuid": "REDACTED",
"ansible_product_version": "None",
"ansible_python_version": "2.7.3",
"ansible_selinux": false,
"ansible_ssh_host_key_dsa_public": "REDACTED KEY VALUE"
"ansible_ssh_host_key_ecdsa_public": "REDACTED KEY VALUE"
"ansible_ssh_host_key_rsa_public": "REDACTED KEY VALUE"
"ansible_swapfree_mb": 665,
"ansible_swaptotal_mb": 1021,
"ansible_system": "Linux",
"ansible_system_vendor": "VMware, Inc.",
"ansible_user_id": "root",
"ansible_userspace_architecture": "x86_64",
"ansible_userspace_bits": "64",
"ansible_virtualization_role": "guest",
"ansible_virtualization_type": "VMware"
引用返回的fact变量：
{{ ansible_devices.sda.model }} #第一个硬盘的model
{{ ansible_hostname } #ansible 远程主机名
在模板和条件判断中会经常使用facts。
关闭facts
如果你不需要使用你主机的任何fact数据,你已经知道了你系统的一切,那么你可以关闭fact数据的获取。
- hosts: whatever gather_facts: false
本地facts
ansible facts主要是用于获取远程系统的数据，从而可以在playbook中作为变量使用。
通常facts中的数据是由Ansible中的 ‘setup’模块自动发现的.用户也可以自定义facts模块。
如果远程受管理的机器有一个 “/etc/ansible/facts.d” 目录,那么在该目录中任何以 ”.fact”结尾的文件都可以在Ansible中提供局部facts.
这些文件可以是JSON,INI或者任何可以返回JSON的可执行文件.
例如建设有一个 /etc/ansible/facts.d/perferences.fact文件:
[general] asdf=1 bar=2
这将产生一个名为 “general” 的哈希表fact,里面成员有 ‘asdf’ 和 ‘bar’. 可以这样验证:
ansible <hostname> -m setup -a "filter=ansible_local"
然后你会看到有以下fact被添加:
"ansible_local": {
"preferences": {
"general": {
"asdf" : "1",
"bar" : "2"
}
}
}
而且也可以在template或palybook中访问该数据:
{{ ansible_local.preferences.general.asdf }}
本地命名空间放置其它用户提供的fact或者playbook中定义的变量覆盖系统facts值。
如果你有个一个playook,它复制了一个自定义的fact,然后运行它,请显式调用来重新运行setup模块，
这样可以让我们在该playbook中使用这些fact.否则,在下一个play中才能获取这些自定义的fact信息.这里有一个示例:
- hosts: webservers
tasks:
- name: create directory for ansible custom facts
file: state=directory recurse=yes path=/etc/ansible/facts.d
- name: install custom impi fact
copy: src=ipmi.fact dest=/etc/ansible/facts.d
- name: re-read facts after adding custom fact
setup: filter=ansible_local
然而在该模式中你也可以编写一个fact模块,这只不过是多了一个选项。
fact缓存
从一个服务器引用另一个服务器的变量是可行的，比如:
{{ hostvars['asdf.example.com']['ansible_os_family'] }}
如果禁用 “Fact Caching”，为了实现以上功能,Ansible在当前play之前已经与 ‘asdf.example.com’ 通讯过,或者在playbook有其它优先的play.这是ansible的默认配置.
为了避免这些，Ansible 1.8以后版本允许在playbook运行期间保存facts.但该功能需要手动开启.这有什么用处那？
想象一下,如果我们有一个非常大的基础设施,里面有数千个主机.Fact缓存可以配置在夜间运行,
但小型服务器集群可以配置fact随时运行,或者在白天定期运行.即使开启了fact缓存,也不需要访问所有服务器来引用它们的变量和信息.
使用fact缓存可以跨群组访问变量,即使群组间在当前/user/bin/ansible-playbook执行中并没有通讯过.
为了启用fact缓存,在大多数plays中你可以修改 ‘gathering’ 设置为 ‘smart’ 或者 ‘explicit’,也可以设置 ‘gather_facts’ 为False.
当前,Ansible可以使用两种持久的缓存插件: redis和jsonfile.
可以在ansible.cfg中配置fact缓存使用redis:
[defaults]
gathering = smart
fact_caching = redis
fact_caching_timeout = 86400
# seconds
请执行适当的系统命令来启动和运行redis:
yum install redis
service redis start
pip install redis
请注意可以使用pip来安装Python redis库,在EPEL中的包版本对Ansible来说太旧了.
在当前Ansible版本中,该功能还处于试用状态,Redis插件还不支持端口或密码配置,以后会改善这点.
在ansible.cfg中使用以下代码来配置fact缓存使用jsonfile:
[defaults]
gathering = smart
fact_caching = jsonfile
fact_caching_connection = /path/to/cachedir
fact_caching_timeout = 86400
# seconds
fact_caching_connection 是一个放置在可读目录(如果目录不存在,ansible会试图创建它)中的本地文件路径。
来源：https://www.cnblogs.com/nineep/p/8984251.html