clean up a vm's iso storage repos when it fails to start on xenserver

[Damans227]

Fixes #11984

When a vm fails to start on a XenServer or XCP-ng host, the cleanup removes the vm, its disks and network cards, but leaves its iso storage repositories (<vm>-ISO and <vm>-CONFIGDRIVE-ISO) behind. The stop that follows finds no vm and skips them, and the next start attempt creates another one with the same name. After a few retries there are several repositories with that name, and from then on even a normal stop cant remove them, because the lookup gives up when it finds more than one. This removes both repositories in the start failure cleanup, the same way a normal stop does.

Test:

Added a unit test that fails a vm start and checks both iso repositories of that vm are removed.

On a lab with one XCP-ng 8.2 host: an L2 network with Config Drive for userdata, cluster memory overcommit set to 4, and a 12 GB offering, so CloudStack places the vm but the host fails the start with HOST_NOT_ENOUGH_FREE_MEMORY. Deploy a vm with userdata and an iso attached, start it three times, then change it to a small offering, start it and stop it. After each step, list the vm's storage repos on the host with xe sr-list.

Before: every failed start leaves one more CONFIGDRIVE-ISO repo behind, and the normal stop at the end cant remove them either.

== start 1
== storage repos for i-2-135-VM on the host:
count: 2
== start 2
== storage repos for i-2-135-VM on the host:
count: 4
== start 3
== storage repos for i-2-135-VM on the host:
count: 6
== start with a small offering, then stop
== storage repos for i-2-135-VM on the host after the stop:
uuid ( RO)          : 36637543-7bc3-e47b-c1bb-c983781dad96
    name-label ( RW): i-2-135-VM-CONFIGDRIVE-ISO
uuid ( RO)          : 21d92447-2b4e-0742-4ac2-371fee2811a2
    name-label ( RW): i-2-135-VM-CONFIGDRIVE-ISO
uuid ( RO)          : 7d2818ca-466c-5e8d-0f12-48b201f3e255
    name-label ( RW): i-2-135-VM-CONFIGDRIVE-ISO
uuid ( RO)          : ffbb2a75-d81f-4ded-08d0-d50b26b3c0a2
    name-label ( RW): i-2-135-VM-CONFIGDRIVE-ISO
uuid ( RO)          : fb81ef54-0655-5818-aeb3-3aa84671fbec
    name-label ( RW): i-2-135-VM-CONFIGDRIVE-ISO
uuid ( RO)          : eb655195-c797-dac5-5da6-3c0bbec0f1a2
    name-label ( RW): i-2-135-VM-CONFIGDRIVE-ISO
uuid ( RO)          : 666af859-bba2-4ce1-f787-a9136d19eb9e
    name-label ( RW): i-2-135-VM-CONFIGDRIVE-ISO
count: 7

After: nothing is left after any failed start or after the stop.

== start 1
errortext": "Unable to orchestrate the start of VM instance {\
== storage repos for i-2-137-VM on the host:
count: 0
== start 2
errortext": "Unable to orchestrate the start of VM instance {\
== storage repos for i-2-137-VM on the host:
count: 0
== start 3
errortext": "Unable to orchestrate the start of VM instance {\
== storage repos for i-2-137-VM on the host:
count: 0
== start with a small offering, then stop
"state": "Running"
"state": "Stopped"
== storage repos for i-2-137-VM on the host after the stop:
count: 0

Host log (/var/log/xensource.log) for one failed start, the repo is removed right after the vm:

audit] SR.set_name_label: SR = 'dcd7b1d3-a9e1-ce34-6350-bab18d5ca44a (...)' name-label = 'i-2-137-VM-CONFIGDRIVE-ISO'
audit] VM.start_on: VM = 'f1e47c62-6978-af14-9648-cd33e0007848 (i-2-137-VM)'
Server_error(HOST_NOT_ENOUGH_FREE_MEMORY
audit] VM.destroy: VM = 'f1e47c62-6978-af14-9648-cd33e0007848 (i-2-137-VM)'
audit] SR.forget: SR = 'dcd7b1d3-a9e1-ce34-6350-bab18d5ca44a (i-2-137-VM-CONFIGDRIVE-ISO)'

[Damans227]

@blueorangutan package

[blueorangutan]

@Damans227 a [SL] Jenkins job has been kicked to build packages. It will be bundled with no SystemVM templates. I'll keep you posted as I make progress.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 20.39%. Comparing base (d3f0700) to head (527fbd6).

Additional details and impacted files

@@            Coverage Diff            @@
##               main   #14425   +/-   ##
=========================================
  Coverage     20.39%   20.39%           
+ Complexity    21283    21281    -2     
=========================================
  Files          6481     6481           
  Lines        588040   588042    +2     
  Branches      72021    72021           
=========================================
+ Hits         119957   119960    +3     
+ Misses       455052   455043    -9     
- Partials      13031    13039    +8     

Flag	Coverage Δ
uitests	3.70% <ø> (ø)
unittests	21.70% <100.00%> (+<0.01%)	⬆️

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[blueorangutan]

Packaging result [SF]: ✔️ el8 ✔️ el9 ✔️ el10 ✔️ debian ✔️ suse15. SL-JID 19587