Hi Grant, what storage are you using here? Is the instance in an apparently "working" state before you try and reboot it?

Have you looked into `/usr/bin/rescan-scsi-bus.sh` ? Please see this reference link in the first instance: [1] "When ‘rescan-scsi-bus.sh -i’ is run, script execute as well a LIP_RESET (ISSUE_LIP) which may cause a disruption in I/O on the server and even cause an outage in case of a system running on heavy load."

Are you using multipath? Some helpful commands:

`tail -f /var/log/messages | grep multipath`

`multipathd -k` = will go into mutipath cli. Then while in the cli:

show config

show paths

If the cli is accessible then you're likely using multipath even if 1 path. Then the multipath.conf is taking effect even if it's a default config.

Config files relating to iscsi storage:
/etc/iscsi/iscsid.conf

/etc/multipath/multipath.conf

[1] https://www.thegeekdiary.com/when-to-use-rescan-scsi-bus-sh-i-lip-flag-in-centos-rhel/

Regards,

Tony Pearce

On Wed, 28 Oct 2020 at 03:39, Grant Morley <grant@civo.com> wrote:

Hi all,

We are seeing some oddness on a couple of our compute hosts that seems to be related to iSCSI. On a couple of our hosts I am seeing this error in the nova compute logs:

2020-10-27 18:56:14.814 31490 WARNING os_brick.initiator.connectors.iscsi [req-8613ae69-1661-49cf-8bdc-6fec875d01ba - - - - -] Couldn't find iscsi sessions because iscsiadm err: iscsiadm: could not read session targetname: 5
iscsiadm: could not find session info for session1707

That seems to also stop any instance on the compute host from being able to reboot. Reboots seem to get accepted but the instance never completes and gets stuck in the reboot state:

2020-10-27 19:11:58.891 48612 INFO nova.compute.manager [-] [instance: c8079e85-4777-4615-9d5a-3d1151e11984] During sync_power_state the instance has a pending task (reboot_started_hard). Skip.
2020-10-27 19:11:58.891 48612 INFO nova.compute.manager [-] [instance: 31128f26-910d-411f-98e0-c95dd36f4f0f] During sync_power_state the instance has a pending task (reboot_started_hard). Skip.

Does anyone know of a way to resolve this without rebooting the entire compute host? I can't see any other issues other than the fact there is this iSCSI error which in turn seems to stop nova from processing anything for any instance.

Any advice would be much appreciated.

Regards,

--

Grant Morley

Cloud Engineer, Civo Ltd

Unit H-K, Gateway 1000, Whittle Way
Stevenage, Herts, SG1 2FP, UK

Visit us at www.civo.com
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