Instance Creation Failing due to Failed NFS Mount

Problem

• When attempting to create a VM on a compute host, the following error is observed in the UI or through the CLI:

Exceeded maximum number of retries. Exceeded max scheduling attempts 3 for instance [INSTANCE_ID]. Last exception: Unexpected error while running command.

Command: mount -t nfs -o vers=3,proto=tcp,lookupcache=pos,nolock,noacl [NFS_SERVER_IP]

Traceback (most recent call last):

  File "/var/lib/openstack/lib/python3.10/site-packages/nova/conductor/manager.py", line 690, in build_instances

    scheduler_utils.populate_retry(

  File "/var/lib/openstack/lib/python3.10/site-packages/nova/scheduler/utils.py", line 1017, in populate_retry

    raise exception.MaxRetriesExceeded(reason=msg)

nova.exception.MaxRetriesExceeded: Exceeded maximum number of retries. Exceeded max scheduling attempts 3 for instance [INSTANCE_ID]. Last exception: Unexpected error while running command.

Command: mount -t nfs -o vers=3,proto=tcp,lookupcache=pos,nolock,noacl [NFS_SERVER_IP]:/nfs/share /local/mount/point

Exit code: 32

Stdout: ''

Stderr: 'mount: /local/mount/point: bad option; for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount.<type> helper program.\n'

• VM migration fails due to an NFS mount error on the destination host. During the migration process, the destination host is unable to mount the required NFS share.

Environment

• Platform9 Private Cloud Director - v2025.4 and Higher
• Self Hosted Private Cloud Director Virtualization – v2025.4 and Higher
• Component - Compute, Host

Cause

• The failure occurred because the nfs-common package (which provides the mount.nfs helper utility) was not installed or not properly configured on the destination host. As a result, the system was unable to execute the mount command for the NFS share during the VM migration process. This led to a failure in mounting the NFS volume required for shared storage, preventing the migration from completing successfully.

Diagnostics

1. NFS Volume is not getting created in hosts with the aforementioned error.
2. Attempt manual NFS mount on the destination host.

sudo mount -t nfs -o vers=3 [NFS_SERVER_IP]:/nfs/share /local/mount/point

mount: /local/mount/point: bad option; for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount.<type> helper program.

3. Check if the required package is installed.

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dpkg -l | grep nfs-common

Resolution

1. Manually install nfs-common package on the affected host.

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sudo apt install -y nfs-common

Validation

1. Check if the the volumes are getting properly mounted in the affected hosts.

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$ sudo mount | grep "</nfs/share>"

[NFS_SERVER_IP]:/nfs/share on /local/mount/point/[UUID] type nfs (rw,vers=3,proto=tcp,...)

2. If these steps prove insufficient to resolve the issue, reach out to the Platform9 Support Team for additional assistance.