Puppet Lookup Command: Everything you wanted to know

Puppet Lookup Command Reference


This page covers the puppet lookup command, for performing Hiera lookups from the command line. This is useful for Interactive Hiera lookups. Click here if you are looking for the puppet lookup function.

Since this command needs access to your Hiera data, make sure to run it on a node that has a copy of that data. This usually means logging into a Puppet Server node and running ‘puppet lookup’ with sudo.

The most common version of the puppet lookup command is:

puppet lookup --node --environment --explain


puppet lookup [–help] [–type ] [–merge first|unique|hash|deep]
[–knock-out-prefix ] [–sort-merged-arrays]
[–merge-hash-arrays] [–explain] [–environment ]
[–default ] [–node ] [–facts ]
[–render-as s|json|yaml|binary|msgpack]


The lookup command is a CLI for Puppet’s ‘lookup()’ function. It searches your Hiera data and returns a value for the requested lookup key, so you can test and explore your data. It is a modern replacement for the ‘hiera’ command.

Hiera usually relies on a node’s facts to locate the relevant data sources. By
default, ‘puppet lookup’ uses facts from the node you run the command on, but you can get data for any other node with the ‘–node ‘ option. If possible, the lookup command will use the requested node’s real stored facts from PuppetDB; if PuppetDB isn’t configured or you want to provide arbitrary
fact values, you can pass alternate facts as a JSON or YAML file with ‘–facts

If you’re debugging your Hiera data and want to see where values are coming from, use the ‘–explain’ option.

If ‘–explain’ isn’t specified, lookup exits with 0 if a value was found and 1
otherwise. With ‘–explain’, lookup always exits with 0 unless there is a major error.

You can provide multiple lookup keys to this command, but it only returns a
value for the first found key, omitting the rest.

Puppet Lookup Options

–helpPrint this help message.
–explainExplain the details of how the lookup was performed and where the final value came from (or the reason no value was found).
–nodeSpecify which node to look up data for; defaults to the node where the command is run. Since Hiera’s purpose is to provide different values for different nodes (usually based on their facts), you’ll usually want to use some specific node’s facts to explore your data. If the node where you’re running this command is configured to talk to PuppetDB, the command will use the requested node’s most recent facts. Otherwise, you can override facts with the ‘–facts’ option.
–factsSpecify a .json or .yaml file of key => value mappings to override the facts for this lookup. Any facts not specified in this file maintain their original value.
–environmentLike with most Puppet commands, you can specify an environment on the command line. This is important for lookup because different environments can have different Hiera data.
Specify the merge behavior, overriding any merge behavior from the data’s lookup_options. ‘first’ returns the first value found. ‘unique’ appends everything to a merged, deduplicated array. ‘hash’ performs a simple hash merge by overwriting keys of lower lookup priority. ‘deep’ performs a deep merge on values of Array and Hash type. There are additional options that can be used with ‘deep’.
–knock-out-prefixCan be used with the ‘deep’ merge strategy. Specifies a prefix to indicate a value should be removed from the final result.
–sort-merged-arraysCan be used with the ‘deep’ merge strategy. When this flag is used, all merged arrays are sorted.
–merge-hash-arraysCan be used with the ‘deep’ merge strategy. When this flag is used, hashes WITHIN arrays are deep-merged with their counterparts by position.
–explain-optionsExplain whether a lookup_options hash affects this lookup, and how that hash was assembled. (lookup_options is how Hiera configures merge behavior in data.)
–defaultA value to return if Hiera can’t find a value in data. For emulating calls to the ‘lookup()’ function that include a default.
–typeAssert that the value has the specified type. For emulating calls to the ‘lookup()’ function that include a data type.
–compilePerform a full catalog compilation prior to the lookup. If your hierarchy and data only use the $facts, $trusted, and $server_facts variables, you don’t need this option; however, if your Hiera configuration uses arbitrary variables set by a Puppet manifest, you might need this option to get accurate data. No catalog compilation takes place unless this flag is given.
Specify the output format of the results; “s” means plain text. The default when producing a value is yaml and the default when producing an explanation is s.

Puppet Lookup Examples

Here are some puppet lookup command line examples

To look up ‘key_name’ using the Puppet Server node’s facts:

$ puppet lookup key_name

To look up ‘key_name’ with agent.local’s facts:

$ puppet lookup --node agent.local key_name

To get the first value found for ‘key_name_one’ and ‘key_name_two’ with agent.local’s facts while merging values and knocking out the prefix ‘foo’ while merging:

$ puppet lookup --node agent.local --merge deep --knock-out-prefix foo key_name_one key_name_two

To lookup ‘key_name’ with agent.local’s facts, and return a default value of ‘bar’ if nothing was found:

$ puppet lookup --node agent.local --default bar key_name

To see an explanation of how the value for ‘key_name’ would be found, using agent.local’s facts:

$ puppet lookup --node agent.local --explain key_name

Add a Comment

Your email address will not be published. Required fields are marked *