package installation not considered in playbook - ansible

Question

I got some trouble with automating an installation using ansible.
I use this role (https://github.com/elastic/ansible-elasticsearch) to install elasticsearch on my ubuntu 16.04 server.
The role depends on the package python-jmespath, as mentioned in the documentation.
The role DOES NOT install the package itsself, so i try to install it before role execution.
- hosts: elasticsearch_master_servers
become: yes
tasks:
- name: preinstall jmespath
command: "apt-get install python-jmespath"
- name: Run the equivalent of "apt-get update" as a separate step
apt:
update_cache: yes
- hosts: elasticsearch_master_servers
become: yes
roles:
- role: elastic.elasticsearch
vars:
...
When running the playbook i expect the python-jmespath package to be installed before execuction of role takes place, but role execution fails with
You need to install \"jmespath\" prior to running json_query filter"
When i check if the package is installed manually using dpkg -s python-jmespath i can see the package is installed correctly.
A second run of the playbook (with the package already installed) doesnt fail.
Do I miss an ansible configuration, that updates the list of installed packages during the playbook run ?
Am I doing something wrong in general ?
Thanks in advance

Answer 1

FWIW. It's possible to tag installation tasks and install the packages in the first step. For example
- name: install packages
package:
name: "{{ item.name }}"
state: "{{ item.state|default('present') }}"
state: present
loop: "{{ packages_needed_by_this_role }}"
tags: manage_packages
Install packages first
shell> ansible_playbook my-playbook.yml -t manage_packages
and then run the playbook
shell> ansible_playbook my-playbook.yml
Notes
This approach makes checking of the playbooks with "--check" much easier.
Checking idempotency is also easier.
With tags: [manage_packages, never] the package task will be skipped when not explicitly selected. This will speed up the playbook.