command line - Ansible idempotent MySQL installation Playbook -

i want setup mysql server on aws, using ansible configuration management. using default ami amazon (ami-3275ee5b), uses yum package management.

when playbook below executed, goes well. when run second time, task configure root credentials fails, because old password of mysql doesn't match anymore, since has been updated last time ran playbook.

this makes playbook non-idempotent, don't like. want able run playbook many times want.

- hosts: staging_mysql   user: ec2-user   sudo: yes    tasks:     - name: install mysql       action: yum name=$item       with_items:         - mysql-python         - mysql         - mysql-server      - name: start mysql service       action: service name=mysqld state=started      - name: configure root credentials       action: command mysqladmin -u root -p $mysql_root_password 

what best way solve this, means make playbook idempotent? in advance!

i posted on coderwall, i'll reproduce dennisjac's improvement in comments of original post.

the trick doing idempotently knowing mysql_user module load ~/.my.cnf file if finds one.

i first change password, copy .my.cnf file password credentials. when try run second time, myqsl_user ansible module find .my.cnf , use new password.

- hosts: staging_mysql   user: ec2-user   sudo: yes    tasks:     - name: install mysql       action: yum name={{ item }}       with_items:         - mysql-python         - mysql         - mysql-server      - name: start mysql service       action: service name=mysqld state=started      # 'localhost' needs last item idempotency, see     # http://ansible.cc/docs/modules.html#mysql-user     - name: update mysql root password root accounts       mysql_user: name=root host={{ item }} password={{ mysql_root_password }} priv=*.*:all,grant       with_items:         - "{{ ansible_hostname }}"         - 127.0.0.1         - ::1         - localhost      - name: copy .my.cnf file root password credentials       template: src=templates/root/.my.cnf dest=/root/.my.cnf owner=root mode=0600 

the .my.cnf template looks this:

[client] user=root password={{ mysql_root_password }} 

edit: added privileges recommended dhananjay nene in comments, , changed variable interpolation use braces instead of dollar sign.