How to obtain a value from one host in a play, and apply the value on another host.

[Frits Hoogland]

I am trying to orchestrate a database replication setup. This means I need to read configuration details from the master node, and apply this on the slave to facilitate the replication setup.

I try to read a configuration value, which works (master has 'primary' set to true):

  - name: get audit file dest from database

    action: "shell export ORACLE_SID={{ oracle_sid }}; export ORACLE_HOME={{ oracle_home }}; printf \"set head off\nselect value from v\\$parameter where name = 'audit_file_dest';\" | $ORACLE_HOME/bin/sqlplus -S / as sysdba | grep -v ^$"

    when: primary

    register: audit_file_dest

Then I try to apply the value on the slave (slave has 'standby' set to true):

  - name: create audit file dest on standby

    file: path={{ audit_file_dest.stdout }} state=directory

    when: standby

This is how the execution looks like:

TASK: [get audit file dest from database] *************************************

skipping: [192.168.39.142]

changed: [192.168.39.139]

TASK: [create audit file dest on standby] *************************************

skipping: [192.168.39.139]

fatal: [192.168.39.142] => One or more undefined variables: 'dict object' has no attribute 'stdout'

When using the debug module, I see the problem:

TASK: [debug var=audit_file_dest] *********************************************

ok: [192.168.39.142] => {

    "audit_file_dest": {

        "changed": false,

        "skipped": true

    }

}

ok: [192.168.39.139] => {

    "audit_file_dest": {

        "changed": true,

        "cmd": "export ORACLE_SID=test; export ORACLE_HOME=/u01/app/oracle/product/11.2.0.4/dbhome_1; printf \"set head off\nselect value from v\\$parameter where name = 'audit_file_dest';\" | $ORACLE_HOME/bin/sqlplus -S / as sysdba | grep -v ^$",

        "delta": "0:00:00.035030",

        "end": "2014-12-24 15:54:41.230344",

        "invocation": {

            "module_args": "export ORACLE_SID=test; export ORACLE_HOME=/u01/app/oracle/product/11.2.0.4/dbhome_1; printf \"set head off\nselect value from v\\$parameter where name = 'audit_file_dest';\" | $ORACLE_HOME/bin/sqlplus -S / as sysdba | grep -v ^$",

            "module_name": "shell"

        },

        "rc": 0,

        "start": "2014-12-24 15:54:41.195314",

        "stderr": "",

        "stdout": "/u01/app/oracle/admin/test/adump",

        "stdout_lines": [

            "/u01/app/oracle/admin/test/adump"

        ],

        "warnings": []

    }

}

Because I try to use the variable on an host on which the variable was not filled, there is not stdout for it.

How can I simply obtain a value on one host for use on another? In this case I would love to make the registered variable contents global.

It can't be that this is a unique situation? Or is there another way that I should do this?

Thanks

[Brian Coca]

register stays on the host and gets reset in the loop to reflect the
task was skipped, you might want to use a subsequent set_fact and then
access the variable thourgh hostvars[<primary_host_name>].

--
Brian Coca

[Frits Hoogland]

Thank you Brian!

Can you help me a bit with that?

Please mind I created a group of one called 'primary' and a group of one called 'standby' in the hosts file, not sure if that can be used.

I used that to have specific per node variables declared.

It would really help in this specific case to have a value/status obtained on one node to configure the other or others. How is that normally done with Ansible?

Cheers, 

Frits

[Brian Coca]

you can access the data from other nodes through hostvars:

hostvars[<hostname>][<varname>]

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--
Brian Coca

[Frits Hoogland]

Thank you again Brian, for all your help.

As I've stated in the explanation of the problem, I've declared groups in the host file. It's a group of one, but still a group.

I solved this in the following way:

1. get the value 

  - name: get audit file dest from database

    action: "shell export ORACLE_SID={{ oracle_sid }}; export ORACLE_HOME={{ oracle_home }}; printf \"set head off\nselect value from v\\$parameter where name = 'audit_file_dest';\" | $ORACLE_HOME/bin/sqlplus -S / as sysdba | grep -v ^$"

    when: primary

    register: audit_file_dest

2. set the registered variable as fact

  - name: register audit file dest

    set_fact: audit_file_dest="{{ audit_file_dest.stdout }}"

    when: primary

3. call the fact from another host via the group name and (mandatory, as far as I can see) host group number:

  - name: create audit file dest on standby

    file: path={{ hostvars[groups['primary'][0]]['audit_file_dest'] }} state=directory

    when: standby

Cheers,

Frits