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Bug #23891

closed

unable to perform a "rbd-nbd map" without forgroud flag

Added by Marc Schöchlin about 6 years ago. Updated about 6 years ago.

Status:
Duplicate
Priority:
Normal
Assignee:
-
Target version:
-
% Done:

0%

Source:
Tags:
Backport:
Regression:
Yes
Severity:
1 - critical
Reviewed:
Affected Versions:
Ceph - v12.2.5
ceph-qa-suite:
rbd
Pull request ID:
Crash signature (v1):
Crash signature (v2):

Description

I would like to map a rbd using rbd-nbd. Without adding the foreground flag it is not possible to map the device.

The command listed beyond, are executed on a mon server (same thing happens on other servers)

Not working scenario: running rbd-nbd as background proccess

Shell 1:

# rmmod nbd
rmmod: ERROR: Module nbd is not currently loaded
# rbd-nbd map  --nbds_max 16 RBD_XenStorage-07449252-bf96-4daa-b0a6-687b7f1c369c/RBD-17efad10-6807-433f-879a-c59b511f895c
-> it blocks probably forever

I attached a strace of the problem situation

# strace -frvT -s128 -o /tmp/fail.strace rbd-nbd map  --nbds_max 16 RBD_XenStorage-07449252-bf96-4daa-b0a6-687b7f1c369c/RBD-17efad10-6807-433f-879a-c59b511f895c

Shell 2:

# rbd-nbd list-mapped
-> no output
# lsmod |grep nbd
-> no output

Working scenario running rbd-nbd in foreground:

Shell 1:

# rbd-nbd map  -d --nbds_max 16 RBD_XenStorage-07449252-bf96-4daa-b0a6-687b7f1c369c/RBD-17efad10-6807-433f-879a-c59b511f895c
2018-04-26 23:22:19.681903 7fde4b442e80  0 ceph version 12.2.5 (cad919881333ac92274171586c827e01f554a70a) luminous (stable), process (unknown), pid 326958
2018-04-26 23:22:19.681919 7fde4b442e80  0 pidfile_write: ignore empty --pid-file
/dev/nbd0
-> Blocking, because its running as foreeground proccess

Shell 2:

# rbd-nbd list-mapped
pid    pool                                                image                                    snap device    
326958 RBD_XenStorage-07449252-bf96-4daa-b0a6-687b7f1c369c RBD-17efad10-6807-433f-879a-c59b511f895c -    /dev/nbd0 
# blockdev --getsize64 /dev/nbd0
21474836480
# blockdev --setra 1024 /dev/nbd0
# blockdev --getra  /dev/nbd0
1024
# rbd-nbd unmap /dev/nbd0

Shell 1:

-> terminates in unmap
2018-04-26 23:24:55.660478 7fdded7ba700  0 rbd-nbd: disconnect request received

Our System:

  • Luminous/12.2.5
  • Ubuntu 16.04
  • 5 OSD Nodes (24*8 TB HDD OSDs, 48*1TB SSD OSDS, Bluestore, 6Gb Cache per OSD)
  • Size per OSD, 192GB RAM, 56 HT CPUs)
  • 3 Mons (64 GB RAM, 200GB SSD, 4 visible CPUs)
  • 2 * 10 GBIT, SFP+, bonded xmit_hash_policy layer3+4

Files

fail.strace (996 KB) fail.strace Marc Schöchlin, 04/26/2018 09:33 PM
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