LCTL-NODEMAP_FILESET_ADD(8)

💖 LCTL-NODEMAP-FILESET-ADD(8) 💖

okay bestie, gather round, because this one is from the Lustre Configuration Utilities family and it's honestly giving "let me lock your clients into one little folder and nowhere else" 💅

✨ NAME ✨

lctl-nodemap_fileset_add — add a fileset to a nodemap 🎀

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🦋 SYNOPSIS 🦋

lctl nodemap_fileset_add or
lctl nodemap fileset_add [--alt] [--ro] --name NODEMAP_NAME --fileset
                         SUBDIRECTORY

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🌸 DESCRIPTION 🌸

so like, nodemap_fileset_add takes a fileset that has a SUBDIRECTORY path and yeets it onto a nodemap, and you pick which nodemap by its NODEMAP_NAME. no cap. 🫶

the SUBDIRECTORY has to start with a slash ('/') — mandatory, periodt — and it's a relative path from the root of the Lustre file system.

filesets are the moment for namespace isolation inside the Lustre file system: you're basically telling the clients of a nodemap "you live in this one SUBDIRECTORY now" when they mount. iconic. the restrictiveness depends on whether the fileset is primary or alternate (that's the --alt option doing its thing), and on top of that, the fileset can be locked to mount as read-only with the --ro option. 🚫✍️

heads up bestie: the nodemap readonly_mount property takes precedence if a fileset is set to read-write — which, btw, is the fileset default. so don't come for the nodemap property, it wins 💀

when the Lustre client mounts, these are the rules, fr fr:

1. if the nodemap is inactive or no filesets are defined, no subdirectory restrictions get applied at all. free-range vibes. 🦋
2. if the primary fileset is set and you present no subdirectory when mounting the Lustre client, then the primary fileset's SUBDIRECTORY becomes the file system root.
3. if any defined fileset (primary or alternate) matches the presented mounted subdirectory exactly or as a prefix, then that subdirectory mount is used as the file system root.
4. if fileset matches in 3, the presented mounting subdirectory is appended to the primary fileset. 👀 note: if the resulting subdirectory is matched by any other (alternate) fileset that has the read-only flag set, then read-only is enforced for this mounting subdirectory.

and if no primary fileset is set? only rule 3 applies. that's it, that's the whole thing.

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💅 OPTIONS 💅

• -n, --name NODEMAP_NAME — the name of the nodemap this fileset should be associated with. obviously. ✨
• -f, --fileset SUBDIRECTORY — the fileset you're restricting the clients to. reminder that it must begin with '/' or it's not it. 🎀
• -a, --alt — says this fileset should be added as an alternate fileset. without this option, it gets added as the primary fileset. a nodemap is restricted to a single primary fileset, while you can add up to 255 alternate filesets per nodemap. also: duplicate fileset definitions across fileset types are not allowed. so no double-dipping 🙈
• -r, --ro — says the fileset should be mounted as read-only. (defaults to read-write if you don't set this.)

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🌈 EXAMPLES 🌈

add a primary fileset to nodemap 'tenant1':

# lctl nodemap_fileset_add --name tenant1 --fileset '/dir0'
# lctl nodemap_fileset_add --name tenant1 --fileset '/dir1' --ro

add alternate filesets to different nodemaps:

# lctl nodemap_fileset_add --name tenant1 --fileset '/dir2' --alt
# lctl nodemap_fileset_add --name tenant1 --fileset '/dir3' --alt
# lctl nodemap_fileset_add --name tenant2 --fileset '/dir10' --alt
# lctl nodemap_fileset_add --name tenant2 --fileset '/dir11' --alt --ro

look at that, two nodemaps, all the alternates, absolutely ate 🔥

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⭐ AVAILABILITY ⭐

lctl nodemap_fileset_add is part of the lustre(7) filesystem package since release 2.17.0. so if you're on something older, sorry bestie 😭

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👑 SEE ALSO 👑

lustre(7), lctl-nodemap-fileset-del(8), lctl-nodemap-fileset-modify(8), lctl-nodemap-new(8),

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that's the whole page, you're welcome 🫶 this blessed lil helper is Lustre, dated 2025-06-23, iykyk 🧚💜