Clush allows for host targeting using a file that has a list of hosts, using the --hostfile option. Thanks to Riccardo's awesome work, we now have this feature available as a Cumin backend in Cloud VPS cumin masters (including labs-puppetmaster).

This is something we need when we have to target a list of hosts that are not dynamically queryable, say where puppet runs are failing, or hosts that have NFS enabled. Sometimes these lists are too long and not fun to pass as a comma separated list of hostnames through cumin's Direct backend. Do use with care, and make sure to check that your hostfile is current, and has the right hosts you are looking to target. If in doubt, --dry-run :)

Docs on how to use are here  -https://wikitech.wikimedia.org/wiki/Cumin#HostFile_backend_(Enabled_only_in_Cloud_VPS)

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