workshop remove giving zfs destroy error "dataset is busy" #1062

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1. jonathan-conder

   self-assigned this

   on Sep 29, 2026
2. jonathan-conder commented on Sep 30, 2026

   

   jonathan-conder

   on Sep 30, 2026

   Contributor

   More actions

   Seems to be caused by canonical/lxd#18933, here's a reproducer:

   #!/bin/sh
   
   set -eu
   
   sudo snap install lxd --revision=40958
   sudo snap refresh --hold lxd
   lxd waitready
   lxd init --auto --storage-backend=zfs
   
   lxc launch images:alpine/3.22 c1
   
   sudo snap restart lxd
   lxd waitready
   lxc start c1 || true
   
   sudo snap refresh lxd --revision=40916
   lxd waitready
   
   for p in $(pgrep -x lxcfs); do
   	grep -q /var/snap/lxd /proc/$p/cmdline || continue
   	echo "lxcfs pid=$p ns=$(sudo readlink /proc/$p/ns/mnt) started=$(ps -o lstart= -p $p)"
   done
   p=$(< /var/snap/lxd/common/lxd.pid)
   echo "lxd   pid=$p ns=$(sudo readlink /proc/$p/ns/mnt)"
   
   lxc stop c1
   grep -H containers/c1 /proc/*/mounts
   lxc delete c1

   Output:

   lxd (5.21/stable) 5.21.8-3a06799 from Canonical✓ installed
   General refreshes of "lxd" held indefinitely
   Launching c1
   2026-09-30T00:09:01Z INFO Waiting for "snap.lxd.daemon.service" to stop.
   Restarted.
   Error: The instance is already running
   2026-09-30T00:09:17Z INFO Waiting for "snap.lxd.daemon.service" to stop.
   lxd 6.9-bf243da from Canonical✓ refreshed
   lxcfs pid=79776 ns=mnt:[4026532716] started=Wed Sep 30 00:09:09 2026
   lxcfs pid=81456 ns=mnt:[4026532717] started=Wed Sep 30 00:09:20 2026
   lxd   pid=81465 ns=mnt:[4026532717]
   /proc/79776/mounts:default/containers/c1 /var/snap/lxd/common/lxd/storage-pools/default/containers/c1 zfs rw,relatime,xattr,posixacl,casesensitive 0 0
   Error: Failed deleting instance "c1" in project "default": Error deleting storage volume: Failed running: zfs destroy -r default/containers/c1: exit status 1 (cannot destroy 'default/containers/c1': dataset is busy)
   
3. saviq-work

   marked Refresh aborted due to Instance "stash-dev-..." already exists #1063 as a duplicate of this issue on Oct 1, 2026