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Dreamwalker
Asked: 2017-07-12 23:34:25 +0800 CST

Using variables / node information in technique?

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I am trying to update a config file using the "File Enforce Content" in the Lines argument I have tried obtaining information about the node using ${rudder.node.hostname} this never gets replaced on the actual node though and remains the same? I am actually after the IP address of the node as well as the host name but using this to test the technique is working since the docs mention it.

Lines Parameter

[Config]
IP=${rudder.node.ipaddress}
Name=${rudder.node.hostname}

Nodes file

[Config]
IP=${rudder.node.ipaddress}
Name=${rudder.node.hostname}

Expected

[Config]
IP=10.0.0.1
Name=node1

(Just as a side note I am struggling to locate a list in the web portal or online of available replacement variables so the ip address one is probably wrong)

rudder

2 Answers

  1. Variables computed by Rudder (ie rudder.node.hostname) cannot be used directly for now in techniques created with the technique editor. (I haven't manage to find the bug https://www.rudder-project.org/redmine/projects/rudder/issues, but there should be one, or you can open a new one if you want)

    A workaround can be to create variable with the variable technique like the following screenshot

    define rudder variable

    and access the variable in technique editor like this:

    ${generic_variable_definition.hostname}

    I think we will work soon on this issue to provide you a way to use it

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  2. I managed to use

    ${sys.host} ${sys.ipv4} ${sys.host}

    The definitions I found here: CFEngine Special Variables

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