Where can I get a list of Ansible pre-defined variables?

Question

I see that Ansible provide some pre-defined variables that we can use in playbooks and template files. For example, the host ip address is ansible_eth0.ipv4.address. Googlei

Answer 1

I know this question has been answered already, but I feel like there are a whole other set of pre-defined variables not covered by the ansible_* facts. This documentation page covers the directives (variables that modify Ansible's behavior), which I was looking for when I came across this page.

This includes some common and some specific use-case directives:

• become: Controls privilege escalation (sudo)
• delegate_to: run task on another host (like running on localhost)
• serial: allows you to run a play across a specific number/percentage of hosts before moving onto next set

Answer 2

I use this simple playbook:

---
# vars.yml
#
# Shows the value of all variables/facts.
#
# Example:
#
#   ansible-playbook vars.yml -e 'hosts=localhost'
#
- hosts: localhost
  tasks:
    - fail: "You must specify a value for `hosts` variable - e.g.: ansible-playbook vars.yml -e 'hosts=localhost'"
      when: hosts is not defined

- hosts: "{{ hosts }}"
  tasks:
    - debug: var=vars
    - debug: var=hostvars[inventory_hostname]

Answer 3

The debug module can be used to analyze variables. Be careful running the following command. In our setup it generates 444709 lines with 16MB:

ansible -m debug -a 'var=hostvars' localhost

I am not sure but it might be necessary to enable facts caching.

If you need just one host use the host name as a key for the hostvars hash:

ansible -m debug -a 'var=hostvars.localhost' localhost

This command will display also group and host variables.

Answer 4

Some variables are not available on every host, e.g. ansible_domain and domain. If the situation needs to be debugged, I login to the server and issue:

user@server:~$ ansible -m setup localhost | grep domain
 [WARNING]: provided hosts list is empty, only localhost is available
    "ansible_domain": "prd.example.com",

Answer 5

There is lot of variables defined as Facts -- http://docs.ansible.com/ansible/playbooks_variables.html#information-discovered-from-systems-facts

"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"

Answer 6

Note the official docs on connection configuration variables or "behavioral" variables - which aren't listed in host vars, appears to be List of Behavioral Inventory Parameters in the Inventory documentation.

P.S. The sudo option is undocumented there (yes its sudo not ansible_sudo as you'd expect ...) and probably a couple more aren't, but thats best doc I've found on em.