blockdevice: add DMMultipathDevices for DM-multipath sysfs parsing#796
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sradco wants to merge 1 commit intoprometheus:masterfrom
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blockdevice: add DMMultipathDevices for DM-multipath sysfs parsing#796sradco wants to merge 1 commit intoprometheus:masterfrom
sradco wants to merge 1 commit intoprometheus:masterfrom
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jsafrane
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Mar 16, 2026
blockdevice/dm_multipath.go
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| suspended := false | ||
| if val, err := util.ReadUintFromFile(fs.sys.Path(sysBlockPath, entry.Name(), sysBlockDM, "suspended")); err == nil { |
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The code looks good overall - it reads the right values from the right sysfs files.
The only thing I noticed is that stats.go returns error on any Read / parse errors, while this file ignores them. I let Prometheus folks judge what's right here.
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Typically we don't ignore errors and try and pass them back so the user of the library can decide what to do about errors.
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+1. Thanks.
I updated the PR now with the fix.
Add DMMultipathDevices() method to blockdevice.FS that discovers Device Mapper multipath devices by scanning /sys/block/dm-* and filtering on dm/uuid prefix "mpath-". For each multipath device it reads the device name, UUID, suspended state, size, and enumerates underlying path devices with their raw state from /sys/block/<path>/device/state. This provides the sysfs parsing layer that node_exporter's dmmultipath collector will import, following the established pattern where collectors delegate filesystem parsing to procfs. Signed-off-by: Shirly Radco <sradco@redhat.com> Co-authored-by: AI Assistant <noreply@cursor.com>
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Add DMMultipathDevices() method to blockdevice.FS that discovers Device Mapper multipath devices by scanning /sys/block/dm-* and filtering on dm/uuid prefix "mpath-". For each multipath device it reads the device name, UUID, suspended state, size, and enumerates underlying path devices with their raw state from
/sys/block//device/state.
This provides the sysfs parsing layer that node_exporter's dmmultipath collector will import, following the established pattern where collectors delegate filesystem parsing to procfs.
This is the parsing layer for prometheus/node_exporter#3581