CODEWITHSUNDEEP
linuxansible
Willem Noorduin
Willem Noorduin

Reputation: 197

Ansible and conditional install of software

Ansible is great for rolling out (in our case JBoss). One part of the playbook is:

- name: copy jboss-eap-6.2.0.tar.gz to server
  action: copy src=jboss-eap-6.2.0.tar.gz
               dest=/tmp/jboss-eap-6.2.0.tar.gz
               owner=root
               group=root

- name: Extracting jboss-eap-6.2.0.tar.gz
  command: /bin/tar xfz /tmp/jboss-eap-6.2.0.tar.gz -C /opt

which works like a charm, except it works every time, and I would like Ansible to stop the playbook when JBoss is already installed (in our case, the test is if /opt/jboss-eap-6.2.0 does exist. What is the neatest way to do this ? Can you provide a test if something exist on a target server in a when-clause ?

Upvotes: 0

Views: 1904

Answers (1)

Marcin Płonka
Marcin Płonka

Reputation: 2950

If you only wanted to skip command execution then creates parameter of command module would solve your problem. It instructs the module to skip execution of the command if destination file/directory already exists.

Here's an example:

- name: Extracting jboss-eap-6.2.0.tar.gz
  command: creates=/opt/jboss_dir /bin/tar xfz /tmp/jboss-eap-6.2.0.tar.gz -C /opt

Your particular case is a bit more tricky. Firstly, your archive may not survive restarts because you're copying to /tmp, so it may be copied every time you execute the playbook. Secondly it may be required to introduce an extra task only to check for jboss directory existence.

The following task will:

  • create /opt/jboss_dir directory if it doesn't exist yet, the result of this task will be stored in jbossDirectory variable
  • if jbossDirectory has changed status, the archive will be copied to /tmp
  • the same changed status will also cause extraction of archive

Example playbook:

- name: create jboss directory
  file: state=directory dest=/opt/jboss_dir owner=root user=root
  register: jbossDirectory

- name: copy jboss-eap-6.2.0.tar.gz to server
  copy: src=jboss-eap-6.2.0.tar.gz dest=/tmp/jboss-eap-6.2.0.tar.gz owner=root group=root
  when: jbossDirectory|changed

- name: extracti jboss-eap-6.2.0.tar.gz
  command: /bin/tar xfz /tmp/jboss-eap-6.2.0.tar.gz -C /opt
  when: jbossDirectory|changed

Upvotes: 2

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