In my inventory I define hosts like this:
[server1]
141.151.176.223
I am looking for a variable which keeps the server1 name, as I am using it to define server hostname.
inventory_hostname is set to 141.151.176.223
ansible_hostname as well as inventory_hostname_short is set to 148.
To workaround this problem I am setting my own variable like this:
[server1]
141.151.176.223 hostname=server1
but I am not satisfied with this approach.
Any ideas?
Explanation
If the inventory file was defined this way:
[server1_group]
server1 ansible_host=141.151.176.223
Then you can access:
server1 with the inventory_hostname fact;
141.151.176.223 with the ansible_host fact;
server1_group with group_names|first (group_names fact contains a list of all groups server belongs to, first selects the first element from that list).
Regardless of the above, ansible_hostname fact contains the host name as defined on the host itself (the value is set during facts gathering).
Solution
You should use a standard ansible_host declaration to point to the target's IP address and set the inventory hostname to however you want to refer to the server in Ansible playbooks.
In particular you can skip groups definition altogether and define just:
server1 ansible_host=141.151.176.223
The [server1] declaration is the name of a group, not a host (even if you only assign a single host to that group).
As ansible allows a host to be placed in multiple groups, you can only get the names as an array: http://docs.ansible.com/ansible/latest/playbooks_variables.html#magic-variables-and-how-to-access-information-about-other-hosts
So I think the workaround that you found is the way to go, unless you can use real host names instead of IP addresses (using DNS or just static hosts file).
Related
In my ansible host inventory, i got 3 host ip as below
[host-group-1]
123.23.23.21
123.23.23.22
i have a variable as below
host_list:
- { fileName: "master.xml", IP: {{ get_current_Execution_ip }} }
- { fileName: "slave.xml", IP: {{ get_current_Execution_ip }} }
I have a task which will do some logic in the jinja2 template based on value get from IP. My question is how can i use this {{ get_current_Execution_ip }} to get the current IP the file being constructed via jinja2 template based on respective server. For instance, if the file contructing in 123.23.23.21, the IP value should be 123.23.23.21, if contructing in server 123.23.23.22, the IP value should be 123.23.23.22
With your inventory set up like that, you can just access the variable inventory_hostname. If you change your inventory to look something like
[host_group_1]
host1 ansible_host=123.23.23.21
host2 ansible_host=123.23.23.22
then you can instead access the IP with the ansible_host variable (which is also available in the first case).
If you change your inventory to not list IP addresses at all (instead relying on resolving the name through DNS), then you probably want to look at some of the answers to this question.
I'm writing a role thats creates virtual machines & configures them. I need to perform a few tasks on the VM's before their DNS entries are created.
How can I get the task to connect to a known IP address instead of the usual ansible_host variable (FQDN)? I can't set it in the inventory file since the IP is not known when it is created.
TIA
The inventory file can use IP addresses. See the jumper example in https://docs.ansible.com/ansible/latest/user_guide/intro_inventory.html.
The way you typically handle this is to use Ansible's add_host module, which lets you create inventory entries dynamically during your playbook run. A task looks something like:
- name: add host to inventory
add_host:
name: my_new_host
ansible_host: "{{ new_host_ipaddr }}"
groups: [webservers]
You can see an example of this in action here (just search for add_host).
I'm using the vmware_guest module to create a bunch of vms.
Is there anyway to use a pattern for both the hostname and IP address?
For example I want to create 5 master vms with hostname/IP like:
master1 10.123.0.1
master2 10.123.0.2
master3 10.123.0.3
etc.
So an inventory yaml with something like the following:
all:
children:
Elvis:
children:
masterNodes:
hosts:
master[1-5]:
ansible_host: 10.123.0.[1-5]
slaveNodes:
hosts:
slave[1-10]:
ansible_host: 10.124.0.[1-10]
Also, is there a way to run a playbook for a specific parent:child group?
How can I run a play for Elvis:masterNodes only? If for instance, the same inventory yaml has another parent child group Bono:masterNodes
Is there anyway to use a pattern for both the hostname and IP address?
No. Instead, Ansible allows running a script to generate an inventory - it is trivial to implement a loop populating inventory-hostname along with IP address in Python (apparently it was made clear as early as in July 2013, although in the same thread someone suggested a workaround).
Also, is there a way to run a playbook for a specific parent:child group?
No. There is no hierarchy in Ansible inventory; the namespace is flat; there are no child groups; Ansible operates on host/group sets.
In effect, you can't have distinct (sub)groups bearing the same name. The contents of those (sub)groups will be merged. So if Elvis contains a group masterNodes and you execute a play with hosts:Elvis declaration, it will run on all hosts defined for masterNodes anywhere (including in Bono:masterNodes).
I have a rather simple hosts file
[clients]
qas0062
[dbs_server]
qas0063
For the users of the project we don't want them to modify hosts file but rather we have a separate user.config.yml file that contain various user-configurable parameters. There we have entry such as
dbs_server: qas0065
So the question is: is it possible to use a variable in the hosts file that would use a value defined in user.config.yml? And what would be the format?
Pretty sure you can't templatize the actual host key entry in the inventory, but you can templatize the value of its ansible_host connection var to achieve roughly the same effect, eg:
[clients]
clienthost ansible_host="{{ clienthost_var }}"
[dbs_server]
dbsserver ansible_host="{{ dbsserver_var }}"
then set the value of those vars from external vars before the play starts executing (eg, with the vars_files directive or -e).
There is another way to do the same thing. We can simply refer to values in the hosts (inventory) file by using the following syntax in our playbook
host={{ groups['dbs_server'][0] }}
This works well when you have one entry in the group (db_server in this specific case)
I set up group of test VMs (with pure Debian) to play with, all of them are on test network so it is self-contained group of VM. These VMs be destroyed soon so I don't want to add its names to DNS while I need to have them communicate oven hostnames.
Is there any way I can form /etc/hosts files on these VMs based on hosts IPs from Ansible hosts file?
I can set hostnames like that
192.168.0.5 myhostname=host01.local
192.168.0.6 myhostname=host02.local
so I think I can somehow form /etc/hosts like that:
{{ ip }} {{ myhostname }}
but can archive that. I think I can iterate over group['all'] and use lineinfile to add lines to /etc/hosts, but it won't work for me so far.
You can use the inventory_file variable to get the path filename of the hosts file:
Also available, inventory_dir is the pathname of the directory holding Ansible’s inventory host file, inventory_file is the pathname and the filename pointing to the Ansible’s inventory host file.
Reference
You can read its variables with something like:
tasks:
- local_action: shell cat {{ inventory_file }}
register: result
As recommended here. More on local actions here.
You can then use jinja filters and loops to use the variable.