could you post the output of "systemctl show ssd-docs-oreilly.mount"? note that none of this is PVE, it's all systemd
one thing that you might need to add is an explicit dependency on the mountpoint where the iso file is located - e.g., if it is on one of your non-/ ZFS pools, those need to be imported and mounted first.. "man fstab" has more details on the syntax and what not, but you can also write a mount unit instead of the fstab line if you are more comfortable with that.
Here it is:
root@pvetest:~# systemctl show --no-pager ssd-docs-oreilly.mount
Where=/ssd/docs/oreilly
What=/ssd/docs/oreilly_v6.iso
Options=loop,ro
Type=iso9660
TimeoutUSec=1min 30s
ControlPID=0
DirectoryMode=0755
SloppyOptions=no
LazyUnmount=no
ForceUnmount=no
ReadWriteOnly=no
Result=exit-code
UID=[not set]
GID=[not set]
Slice=system.slice
ControlGroupId=0
MemoryCurrent=[not set]
MemoryAvailable=infinity
CPUUsageNSec=3037000
TasksCurrent=[not set]
IPIngressBytes=[no data]
IPIngressPackets=[no data]
IPEgressBytes=[no data]
IPEgressPackets=[no data]
IOReadBytes=18446744073709551615
IOReadOperations=18446744073709551615
IOWriteBytes=18446744073709551615
IOWriteOperations=18446744073709551615
Delegate=no
CPUAccounting=yes
CPUWeight=[not set]
StartupCPUWeight=[not set]
CPUShares=[not set]
StartupCPUShares=[not set]
CPUQuotaPerSecUSec=infinity
CPUQuotaPeriodUSec=infinity
IOAccounting=no
IOWeight=[not set]
StartupIOWeight=[not set]
BlockIOAccounting=no
BlockIOWeight=[not set]
StartupBlockIOWeight=[not set]
MemoryAccounting=yes
DefaultMemoryLow=0
DefaultMemoryMin=0
MemoryMin=0
MemoryLow=0
MemoryHigh=infinity
MemoryMax=infinity
MemorySwapMax=infinity
MemoryLimit=infinity
DevicePolicy=auto
TasksAccounting=yes
TasksMax=9386
IPAccounting=no
ManagedOOMSwap=auto
ManagedOOMMemoryPressure=auto
ManagedOOMMemoryPressureLimit=0
ManagedOOMPreference=none
UMask=0022
LimitCPU=infinity
LimitCPUSoft=infinity
LimitFSIZE=infinity
LimitFSIZESoft=infinity
LimitDATA=infinity
LimitDATASoft=infinity
LimitSTACK=infinity
LimitSTACKSoft=8388608
LimitCORE=infinity
LimitCORESoft=0
LimitRSS=infinity
LimitRSSSoft=infinity
LimitNOFILE=524288
LimitNOFILESoft=1024
LimitAS=infinity
LimitASSoft=infinity
LimitNPROC=31288
LimitNPROCSoft=31288
LimitMEMLOCK=8388608
LimitMEMLOCKSoft=8388608
LimitLOCKS=infinity
LimitLOCKSSoft=infinity
LimitSIGPENDING=31288
LimitSIGPENDINGSoft=31288
LimitMSGQUEUE=819200
LimitMSGQUEUESoft=819200
LimitNICE=0
LimitNICESoft=0
LimitRTPRIO=0
LimitRTPRIOSoft=0
LimitRTTIME=infinity
LimitRTTIMESoft=infinity
OOMScoreAdjust=0
CoredumpFilter=0x33
Nice=0
IOSchedulingClass=2
IOSchedulingPriority=4
CPUSchedulingPolicy=0
CPUSchedulingPriority=0
CPUAffinityFromNUMA=no
NUMAPolicy=n/a
TimerSlackNSec=50000
CPUSchedulingResetOnFork=no
NonBlocking=no
StandardInput=null
StandardOutput=journal
StandardError=inherit
TTYReset=no
TTYVHangup=no
TTYVTDisallocate=no
SyslogPriority=30
SyslogLevelPrefix=yes
SyslogLevel=6
SyslogFacility=3
LogLevelMax=-1
LogRateLimitIntervalUSec=0
LogRateLimitBurst=0
SecureBits=0
CapabilityBoundingSet=cap_chown cap_dac_override cap_dac_read_search cap_fowner cap_fsetid cap_kill cap_setgid cap_setuid cap_setpcap cap_linux_immutable cap_net_bind_service cap_net_broadcast cap_net_admin cap_net_raw cap_ipc_lock cap_ipc_owner cap_sys_module cap_sys_rawio cap_sys_chroot cap_sys_ptrace cap_sys_pacct cap_sys_admin cap_sys_boot cap_sys_nice cap_sys_resource cap_sys_time cap_sys_tty_config cap_mknod cap_lease cap_audit_write cap_audit_control cap_setfcap cap_mac_override cap_mac_admin cap_syslog cap_wake_alarm cap_block_suspend cap_audit_read cap_perfmon cap_bpf cap_checkpoint_restore
DynamicUser=no
RemoveIPC=no
PrivateTmp=no
PrivateDevices=no
ProtectClock=no
ProtectKernelTunables=no
ProtectKernelModules=no
ProtectKernelLogs=no
ProtectControlGroups=no
PrivateNetwork=no
PrivateUsers=no
PrivateMounts=no
PrivateIPC=no
ProtectHome=no
ProtectSystem=no
SameProcessGroup=yes
UtmpMode=init
IgnoreSIGPIPE=yes
NoNewPrivileges=no
SystemCallErrorNumber=2147483646
LockPersonality=no
RuntimeDirectoryPreserve=no
RuntimeDirectoryMode=0755
StateDirectoryMode=0755
CacheDirectoryMode=0755
LogsDirectoryMode=0755
ConfigurationDirectoryMode=0755
TimeoutCleanUSec=infinity
MemoryDenyWriteExecute=no
RestrictRealtime=no
RestrictSUIDSGID=no
RestrictNamespaces=no
MountAPIVFS=no
KeyringMode=shared
ProtectProc=default
ProcSubset=all
ProtectHostname=no
KillMode=control-group
KillSignal=15
RestartKillSignal=15
FinalKillSignal=9
SendSIGKILL=yes
SendSIGHUP=no
WatchdogSignal=6
Id=ssd-docs-oreilly.mount
Names=ssd-docs-oreilly.mount
Requires=system.slice
RequiredBy=local-fs.target
Conflicts=umount.target
Before=umount.target local-fs.target
After=system.slice systemd-journald.socket -.mount local-fs-pre.target ssd.mount
RequiresMountsFor=/ssd/docs/oreilly_v6.iso /ssd/docs
Documentation="man:fstab(5)" "man:systemd-fstab-generator(8)"
Description=/ssd/docs/oreilly
LoadState=loaded
ActiveState=failed
FreezerState=running
SubState=failed
FragmentPath=/run/systemd/generator/ssd-docs-oreilly.mount
SourcePath=/etc/fstab
UnitFileState=generated
UnitFilePreset=enabled
StateChangeTimestamp=Thu 2024-02-15 10:10:23 CET
StateChangeTimestampMonotonic=8965269
InactiveExitTimestamp=Thu 2024-02-15 10:10:23 CET
InactiveExitTimestampMonotonic=8960110
ActiveEnterTimestampMonotonic=0
ActiveExitTimestampMonotonic=0
InactiveEnterTimestamp=Thu 2024-02-15 10:10:23 CET
InactiveEnterTimestampMonotonic=8965269
CanStart=yes
CanStop=yes
CanReload=yes
CanIsolate=no
CanFreeze=no
StopWhenUnneeded=no
RefuseManualStart=no
RefuseManualStop=no
AllowIsolate=no
DefaultDependencies=yes
OnSuccessJobMode=fail
OnFailureJobMode=replace
IgnoreOnIsolate=yes
NeedDaemonReload=no
JobTimeoutUSec=infinity
JobRunningTimeoutUSec=infinity
JobTimeoutAction=none
ConditionResult=yes
AssertResult=yes
ConditionTimestamp=Thu 2024-02-15 10:10:23 CET
ConditionTimestampMonotonic=8941726
AssertTimestamp=Thu 2024-02-15 10:10:23 CET
AssertTimestampMonotonic=8941728
Transient=no
Perpetual=no
StartLimitIntervalUSec=10s
StartLimitBurst=5
StartLimitAction=none
FailureAction=none
SuccessAction=none
InvocationID=cd119ce26cce4a4388f83b0662b24536
CollectMode=inactive
