CentOS - Jan 2018 - systemd-udevd not applying ATTR to block device at boot

Hi everyone,

I have a udev rule file that contains a singular rule:

SUBSYSTEM=="block", ACTION=="add|change",
ENV{ID_VENDOR}=="*Google*", ENV{DEVTYPE}=="disk",
ATTR{queue/scheduler}:="noop"

When I use a Google Cloud instance and boot it, things work as expected and
/dev/sda (a persistent disk) uses the noop scheduler. If the instance also has a
Local SSD type disk, however, the change in scheduler is not applied. This is a
bit academic, because the Local SSD device uses noop by default (somehow, I
don?t see any udev rules for setting this outside of my own). But, for instance,
if I set the scheduler in the udev rules to ?cfq,? at boot, /dev/sda will use
cfq and /dev/sdb will use noop.

If I run udevadm trigger after boot, then /dev/sdb will use cfq. So, it appears
that at boot time, for some reason, my scheduler is not being applied to
/dev/sdb.

I?ve tried a handful of things:

- changing the order of my udev rule file: I?ve tried 10-, 90-, and 99-
prefixes. My rule file is in /etc/udev/rules.d/.
- using ATTR{queue/scheduler}:="noop" and
ATTR{queue/scheduler}="noop" (both the = and := operator)
- searching the internet for all kinds of variations on ?udev rule not applying
at boot?

but so far, I?ve come up empty-handed. The only thing I can think of is that I
am hitting some sort of race condition and udev is unable to set the ATTR in
/sys, but I?m not sure how I can confirm this.

Below are dumps from udevadm of the block devices, /dev/sda (a Google Cloud
persistent disk that is my root partition) and /dev/sdb (a Google Cloud
ephemeral disk [local SSD] that is mounted at /local-ssd).

Thanks in advance for any assistance!

Nick

# udevadm info -q all -a /dev/sda

  looking at device
'/devices/pci0000:00/0000:00:03.0/virtio0/host0/target0:0:1/0:0:1:0/block/sda':
    KERNEL=="sda"
    SUBSYSTEM=="block"
    DRIVER==""
    ATTR{ro}=="0"
    ATTR{size}=="104857600"
    ATTR{stat}=="   14877      938   923845    15717     2732      310   
82984     4328        0     9685    20033"
    ATTR{range}=="16"
    ATTR{discard_alignment}=="0"
    ATTR{events}==""
    ATTR{ext_range}=="256"
    ATTR{events_poll_msecs}=="-1"
    ATTR{alignment_offset}=="0"
    ATTR{badblocks}==""
    ATTR{inflight}=="       0        0"
    ATTR{removable}=="0"
    ATTR{capability}=="50"
    ATTR{events_async}==""

  looking at parent device
'/devices/pci0000:00/0000:00:03.0/virtio0/host0/target0:0:1/0:0:1:0':
    KERNELS=="0:0:1:0"
    SUBSYSTEMS=="scsi"
    DRIVERS=="sd"
    ATTRS{rev}=="1   "
    ATTRS{type}=="0"
    ATTRS{scsi_level}=="7"
    ATTRS{model}=="PersistentDisk  "
    ATTRS{state}=="running"
    ATTRS{unpriv_sgio}=="0"
    ATTRS{queue_type}=="none"
    ATTRS{iodone_cnt}=="0x478f"
    ATTRS{iorequest_cnt}=="0x478f"
    ATTRS{device_busy}=="0"
    ATTRS{evt_capacity_change_reported}=="0"
    ATTRS{timeout}=="30"
    ATTRS{evt_media_change}=="0"
    ATTRS{ioerr_cnt}=="0x0"
    ATTRS{queue_depth}=="256"
    ATTRS{vendor}=="Google  "
    ATTRS{evt_soft_threshold_reached}=="0"
    ATTRS{device_blocked}=="0"
    ATTRS{evt_mode_parameter_change_reported}=="0"
    ATTRS{evt_lun_change_reported}=="0"
    ATTRS{evt_inquiry_change_reported}=="0"
    ATTRS{dh_state}=="detached"
    ATTRS{iocounterbits}=="32"
    ATTRS{inquiry}==""
    ATTRS{vpd_pg80}==""
    ATTRS{vpd_pg83}==""
    ATTRS{eh_timeout}=="10"

  looking at parent device
'/devices/pci0000:00/0000:00:03.0/virtio0/host0/target0:0:1':
    KERNELS=="target0:0:1"
    SUBSYSTEMS=="scsi"
    DRIVERS==""

  looking at parent device
'/devices/pci0000:00/0000:00:03.0/virtio0/host0':
    KERNELS=="host0"
    SUBSYSTEMS=="scsi"
    DRIVERS==""

  looking at parent device '/devices/pci0000:00/0000:00:03.0/virtio0':
    KERNELS=="virtio0"
    SUBSYSTEMS=="virtio"
    DRIVERS=="virtio_scsi"
    ATTRS{device}=="0x0008"
   
ATTRS{features}=="0110000000000000000000000000010000000000000000000000000000000000"
    ATTRS{status}=="0x00000007"
    ATTRS{vendor}=="0x1af4"

  looking at parent device '/devices/pci0000:00/0000:00:03.0':
    KERNELS=="0000:00:03.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="virtio-pci"
    ATTRS{irq}=="11"
    ATTRS{subsystem_vendor}=="0x1af4"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x000000"
    ATTRS{driver_override}=="(null)"
    ATTRS{consistent_dma_mask_bits}=="64"
    ATTRS{dma_mask_bits}=="64"
    ATTRS{local_cpus}=="3"
    ATTRS{device}=="0x1004"
    ATTRS{enable}=="1"
    ATTRS{msi_bus}==""
    ATTRS{local_cpulist}=="0-1"
    ATTRS{vendor}=="0x1af4"
    ATTRS{subsystem_device}=="0x0008"
    ATTRS{numa_node}=="-1"
    ATTRS{d3cold_allowed}=="0"

  looking at parent device '/devices/pci0000:00':
    KERNELS=="pci0000:00"
    SUBSYSTEMS==""
    DRIVERS==""

# udevadm info -q all -a /dev/sdb

  looking at device
'/devices/pci0000:00/0000:00:04.0/virtio1/host1/target1:0:1/1:0:1:0/block/sdb':
    KERNEL=="sdb"
    SUBSYSTEM=="block"
    DRIVER==""
    ATTR{ro}=="0"
    ATTR{size}=="786432000"
    ATTR{stat}=="     219        0    12776      101       16        0    
4096       63        0       66      164"
    ATTR{range}=="16"
    ATTR{discard_alignment}=="0"
    ATTR{events}==""
    ATTR{ext_range}=="256"
    ATTR{events_poll_msecs}=="-1"
    ATTR{alignment_offset}=="0"
    ATTR{badblocks}==""
    ATTR{inflight}=="       0        0"
    ATTR{removable}=="0"
    ATTR{capability}=="50"
    ATTR{events_async}==""

  looking at parent device
'/devices/pci0000:00/0000:00:04.0/virtio1/host1/target1:0:1/1:0:1:0':
    KERNELS=="1:0:1:0"
    SUBSYSTEMS=="scsi"
    DRIVERS=="sd"
    ATTRS{rev}=="1   "
    ATTRS{type}=="0"
    ATTRS{scsi_level}=="7"
    ATTRS{model}=="EphemeralDisk   "
    ATTRS{state}=="running"
    ATTRS{unpriv_sgio}=="0"
    ATTRS{queue_type}=="none"
    ATTRS{iodone_cnt}=="0x141"
    ATTRS{iorequest_cnt}=="0x141"
    ATTRS{device_busy}=="0"
    ATTRS{evt_capacity_change_reported}=="0"
    ATTRS{timeout}=="30"
    ATTRS{evt_media_change}=="0"
    ATTRS{ioerr_cnt}=="0x0"
    ATTRS{queue_depth}=="1024"
    ATTRS{vendor}=="Google  "
    ATTRS{evt_soft_threshold_reached}=="0"
    ATTRS{device_blocked}=="0"
    ATTRS{evt_mode_parameter_change_reported}=="0"
    ATTRS{evt_lun_change_reported}=="0"
    ATTRS{evt_inquiry_change_reported}=="0"
    ATTRS{dh_state}=="detached"
    ATTRS{iocounterbits}=="32"
    ATTRS{inquiry}==""
    ATTRS{vpd_pg80}==""
    ATTRS{vpd_pg83}==""
    ATTRS{eh_timeout}=="10"

  looking at parent device
'/devices/pci0000:00/0000:00:04.0/virtio1/host1/target1:0:1':
    KERNELS=="target1:0:1"
    SUBSYSTEMS=="scsi"
    DRIVERS==""

  looking at parent device
'/devices/pci0000:00/0000:00:04.0/virtio1/host1':
    KERNELS=="host1"
    SUBSYSTEMS=="scsi"
    DRIVERS==""

  looking at parent device '/devices/pci0000:00/0000:00:04.0/virtio1':
    KERNELS=="virtio1"
    SUBSYSTEMS=="virtio"
    DRIVERS=="virtio_scsi"
    ATTRS{device}=="0x0008"
   
ATTRS{features}=="0100000000000000000000000000010000000000000000000000000000000000"
    ATTRS{status}=="0x00000007"
    ATTRS{vendor}=="0x1af4"

  looking at parent device '/devices/pci0000:00/0000:00:04.0':
    KERNELS=="0000:00:04.0"
    SUBSYSTEMS=="pci"
    DRIVERS=="virtio-pci"
    ATTRS{irq}=="10"
    ATTRS{subsystem_vendor}=="0x1af4"
    ATTRS{broken_parity_status}=="0"
    ATTRS{class}=="0x000000"
    ATTRS{driver_override}=="(null)"
    ATTRS{consistent_dma_mask_bits}=="64"
    ATTRS{dma_mask_bits}=="64"
    ATTRS{local_cpus}=="3"
    ATTRS{device}=="0x1004"
    ATTRS{enable}=="1"
    ATTRS{msi_bus}==""
    ATTRS{local_cpulist}=="0-1"
    ATTRS{vendor}=="0x1af4"
    ATTRS{subsystem_device}=="0x0008"
    ATTRS{numa_node}=="-1"
    ATTRS{d3cold_allowed}=="0"

  looking at parent device '/devices/pci0000:00':
    KERNELS=="pci0000:00"
    SUBSYSTEMS==""
    DRIVERS==""