I need to iterate over all hosts and generate config file for hosts that are not contained in group somegroup:
{% for host in groups.all if host not in groups['somegroup'] %}
But if somegroup does not exist, it fails (argument of type 'StrictUndefined' is not iterable).
How do I write this correctly to avoid two different for cycles:
{% if groups['somegroup'] is defined %}
{% for host in groups.all if host not in groups['somegroup'] %}
...
{% endfor %}
{% else %}
{% for host in groups.all %}
...
{% endfor %}
{% endif %}
I think you're looking for the default filter:
{% for host in groups.all if host not in groups['somegroup'] | default([]) %}
Related
I have a template named foo.yml.j2 used in an Ansible task to generate a foo.yml file:
{% for host in ansible_play_hosts_all %}
{{ host }},
{% endfor %}
Everything works fine except I need something like the following statement: For every host in ansible_play_hosts_all except for host==bar do this or that.
Is this achievable or the only way to do this is to categorize my hosts in different groups and use ansible_play_hosts_group?
You can use the reject filter to take your host out of the list so that it is not part of your loop:
{% for host in ansible_play_hosts_all | reject('==', 'bar') %}
{{ host }},
{% endfor %}
There are more options. The trivial one is using the condition in Jinja
{% for host in ansible_play_hosts_all %}
{% if host != 'bar' %}
{{ host }},
{% endif %}
{% endfor %}
Fit the format to your needs.
Example of a complete playbook for testing
- hosts: host_1,host_2,host_3
gather_facts: false
tasks:
- debug:
msg: |
{% for host in ansible_play_hosts_all %}
{% if host != 'host_2' %}
{{ host }},
{% endif %}
{% endfor %}
run_once: true
gives (abridged)
msg: |-
host_1,
host_3,
The next option is to remove blacklisted hosts from the loop, e.g.
blacklist: [host_2]
The template below gives the same result
{% for host in ansible_play_hosts_all|difference(blacklist) %}
{{ host }},
{% endfor %}
I'm trying to generate the following list:
list1:127.0.0.1,127.0.0.2
list2:192.168.1.1,192.168.1.254
From this dictionary:
ip_allowed:
list1:
- 127.0.0.1
- 127.0.0.2
list2:
- 192.168.1.1
- 192.168.1.254
Using the following jinja2 Ansible template:
#ZONE HOST(S) OPTIONS
{% for hosts_key, hosts_value in ip_allowed.iteritems() %}
{% set hosts_dict = hosts_value %}
{% for item in hosts_dict %}
{{ hosts_key }} {{ item }}
{%- if loop.first %},{% endif %}
{% endfor %}
{% endfor %}
But I'm getting the following result:
#ZONE HOST(S) OPTIONS
list1 127.0.0.1, list1 127.0.0.2 list2 192.168.1.1, list2 192.168.1.254
I'm not entirely sure I got the exact format you want out of the template but you'll adapt if needed once you get the idea. Just join each ip in the value.
#ZONE HOST(S) OPTIONS
{% for allowed_item in (ip_allowed | dict2items) %}
{{ allowed_item.key }} {{ allowed_item.value | join(',') }}
{% endfor %}
My template like as blow
{% if hostvars[inventory_hostname].local_zk_server_id is defined %}
zookeeperServers={% for host in {{ groups[{{ target_hosts }}] %}}
"{{ hostvars[host].inventory_hostname }}:2181,"
{% endfor %}
{% endif %}
output ishost1:2181,host2:2181,host3:2181,
How to trim last comma
There are several possible gotchas in your above template regarding variables access. Moreover, rather than trimming the last character in your string, the best solution is probably not to write it. Here is a better solution IMO in my below example fixing all the problems I'm referring to:
{% set zookeeperServers=[] %}
{% if hostvars[inventory_hostname].local_zk_server_id is defined %}
{% for host in groups[target_hosts] %}
{% zookeeperServers.append(hostvars[host].inventory_hostname + ":2181") %}
{% endfor %}
zookeeperServers="{{ zookeeperServers | join(',') }}"
{% endif %}
I have 3 servers A, B, C. When I run the below in j2 template, it pulls all 3 servers.
How can I ignore the server that runs the template?
For ex, if server A runs, it should fetch only server B & C.
"retry_join": ["
{% for host in groups['servers']%}
{{ hostvars[host]['ansible_ssh_host'] }}
{% if not loop.last %}, {% endif %}
{% endfor %}
"]
Exclude inventory_hostname from your servers list:
{% for host in groups['servers'] | difference([inventory_hostname]) %}
You can try a check like this one to verify that your loop variable is not the current host:
{% if host != inventory_hostname %}
{{ hostvars[host]['ansible_ssh_host'] }}
{% endif %}
This article from Ansible.com shows how you can iterate over a group inside of a template file: https://support.ansible.com/hc/en-us/articles/201957887-How-to-loop-over-a-list-of-hosts-in-a-group-inside-of-a-template-
It shows the following code:
{% for host in groups['db_servers'] %}
{{ hostvars[host]['ansible_eth0']['ipv4']['address'] }}
{% endfor %}
It works beautifully, but the servers I want to iterate over are defined by being in multiple groups. So imagine that I want to iterate over all of the servers that are in BOTH the db_servers and qa groups. How can I do this?
I tried to specify the intersection of the group in the same manner I do in my playbook, but that doesn't work. So, when I try:
{% for host in groups['db_servers:&qa'] %}
{{ hostvars[host]['ansible_eth0']['ipv4']['address'] }}
{% endfor %}
I get the following error:
fatal: [54.173.247.115] => {'msg': "AnsibleUndefinedVariable: One or more undefined variables: 'dict object' has no attribute 'db_servers:&qa'", 'failed': True}
Any suggestions on how to iterate over multiple groups in a template file?
Ansible has the intersect filter. See Set Theory Filters.
{% for host in groups['db_servers'] | intersect(groups['qa']) %}
{{ hostvars[host]['ansible_eth0']['ipv4']['address'] }}
{% endfor %}
You could wrap your loop in another for the two server groups:
{% for svrs in ['db_servers', 'qa'] %}
{% for host in groups[svrs] %}
{{ hostvars[host]['ansible_eth0']['ipv4']['address'] }}
{% endfor %}
{% endfor %}