I actually solved my problem, although I'm using some kind of workaround.
1. First thing - max value always returning the second value. It turned out
that hostvars converts fact back to string, so before comparison you have
to reapply int filter.
2. Second thing - finding max value for any number of hosts. I ended up
using this approach:
- shell: "if [ {{ hostvars[inventory_hostname]['seqno'] }} -lt {{
hostvars[item]['seqno'] }} ]; then echo {{ hostvars[item]['seqno'] }}; fi"
with_items: groups['db']
register: result_c
- set_fact: seqno_max={{ hostvars[inventory_hostname]['seqno'] }}
when: result_c.results | map(attribute='stdout') | join('') == ""
It's not the best looking solution, but I guess it's hard to get one with
ansible currently. Ideally it would be great to have something like
groups["db"] | max("seqno")
On Sunday, January 25, 2015 at 2:16:51 PM UTC-8, Karol Stępniewski wrote:
>
> Hello,
>
> I have a group of hosts named "db" with number of nodes that may vary.
> Each node has a fact ("seqno") which is an integer number.
>
> I need to compare this fact among all hosts and choose maximum value, then
> run some actions on one (and only one) host that has this maximum value. In
> case of multiple nodes having the same value, first node should be chosen.
>
> I tried this approach:
>
> - name: find max seqno value
> set_fact: seqno_max={{ [hostvars[groups['db'][0]]['seqno'], hostvars[
> groups['db'][1]]['seqno']] | max }}
>
>
> - name: find single hostname to use as a node with max seqno
> set_fact: seqno_max_host={{ hostvars[item]['inventory_hostname'] }}
> with_items: groups['db'][::-1] # reverse list. if two nodes have the
> same seqno, use first node as starting point.
> when: hostvars[item]['seqno'] == seqno_max
>
>
> - name: Some actions based on a result of previous tasks
> action: # Run some actions
> when: seqno_max_host == inventory_hostname
>
>
>
> But for some reason "max" operator always return the second value. Also
> this approach is valid only if you have arbitrary specified number of hosts
> - It would be best to have a solution that works for any number of hosts.
> Is there a better approach to that?
>
> Karol
>
--
You received this message because you are subscribed to the Google Groups
"Ansible Project" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/ansible-project/93307635-ff16-4cfe-9aae-7a640677932c%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
