CODEWITHSUNDEEP
perlansible
user1514992
user1514992

Reputation: 33

Get ansible to read value from mysql and/or perl script

There may be a much better way to do what i need altogether. I'll give the background first then my current (non-working) approach.

The goal is to migrate a bunch of servers from one SLES 11 to SLES 12 making use of ansible playbooks. The problem is that the newserver and the oldserver are supposed to have the same nfs mounted dir. This has to be done at the beginning of the playbook so that all of the other tasks can be completed. The name of the dir being created can be determined in 2 ways - on the oldserver directly or from a mysql db query for the volume name on that oldserver. The newservers are named migrate-(oldservername). I tried to prompt for the volumename in ansible, but that would then apply the same name to every server. Goal Recap: dir name must be determined from the oldserver, created on new server.

Approach 1: I've created a perl script that ansible will copy to the newserver and it will execute the mysql query, and create the dir itself. There are 2 problems with this - 1) mysql-client needs to be installed on each server. This is completely unneccesary for these servers and would have to then be uninstalled after the query is run. 2) Copying files and remotely executing them seems like a bad approach in general.

Approach 2: Create a version of the above except run it on the ansible control machine (where mysql-client is installed already) and store the values in key:value pairs in a file. Problems - 1) I cannot figure out how to in the perl script determine what hosts Ansible is running against and would have to manually enter them into the perl script. 2) I cannot figure out how to get Ansible to import those values correctly from the file created.

Here's the relevant perl code I have for this - 

 $newserver = migrate-old.server.com
    ($mig, $oldhost) = split(/\-/, $newserver);
    $volname=`mysql -u idm-ansible -p -s -N -e "select vol_name from                 assets.servers where hostname like '$oldhost'";`;

     open(FH, ">vols.yml");
     $values = $newhost{$volname};
     print FH "$newhost:$volname\n";
     close(FH);

My Ansible code is all over the place as I've tried and commented out a ton of things. I can share that here if it is helpful.

Approach 3: Do it completely in Ansible Basically a mysql query for loop over each host. Problem - I have absolutely no idea how to do this. Way too unfamiliar with ansible. I think this is what I would prefer to try and do though.

What is the best approach here? How do I go about getting the right value into ansible to create the correct directory?

Please let me know if I can clarify anything.

Upvotes: 0

Views: 664

Answers (1)

Konstantin Suvorov
Konstantin Suvorov

Reputation: 68269

Goal Recap: dir name must be determined from the oldserver, created on new server.

Will magic variables do?
Something like this:

---
- hosts: old-server
  tasks:
    - shell: "/get-my-mount-name.sh"
      register: my_mount_name

- hosts: new-server
  tasks:
    - shell: "/mount-me.sh --mount_name={{ hostvars['old-server'].my_mount_name.stdout }}"

Upvotes: 0

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