** Description changed:
[ Impact ]
When running autopkgtest for resource-agents in a VM testbed with a
minimal kernel (such as LXD VMs on Jammy running linux-image-kvm), the
`debian/tests/run-ocft iscsi` test fails during SETUP-AGENT with:
ERROR: Warning: Could not load preferences file
/root/.targetcli/prefs.bin.
b'modprobe: FATAL: Module iscsi_target_mod not found in directory
/lib/modules/5.15.0-1109-kvm\n'
ERROR: 'SETUP-AGENT' failed, the return code is 1.
WARNING: SETUP failed, break all tests of 'iscsi'.
command13 FAIL non-zero exit status 1
+ Test log:
+
https://autopkgtest.ubuntu.com/results/autopkgtest-jammy/jammy/amd64/r/resource-agents/20261006_103706_a9699@/log.gz
+
Investigation into the kernel configuration of linux-kvm on Jammy (from
linux-buildinfo-*-kvm) shows:
CONFIG_TARGET_CORE=m
# CONFIG_ISCSI_TARGET is not set
The linux-kvm kernel flavour intentionally disables the LIO iSCSI target
subsystem (`# CONFIG_ISCSI_TARGET is not set`), and there are no
`iscsi_target_mod.ko` modules built for it. Furthermore, simply
installing `linux-modules-extra-*-generic` in `debian/tests/control`
- does not resolve the issue, because `modprobe` cannot load generic
- kernel modules into a running `linux-kvm` kernel due to version, ABI,
- and module signature mismatches.
+ does not resolve the issue, because `modprobe` only looks under
+ `/lib/modules/$(uname -r)/`, and cross-kernel loading via `insmod` is
+ blocked by kernel lockdown (`Lockdown: insmod: unsigned module loading
+ is restricted`).
- Therefore, the cleanest and most robust solution conforming to
- Debian/Ubuntu autopkgtest standards is to check whether
- `iscsi_target_mod` can be probed by the running kernel, and gracefully
- SKIP the test when kernel support is absent. This prevents false-
- positive autopkgtest regressions from blocking proposed migration for
- reverse dependencies such as open-iscsi (LP: #2147499).
+ ---
+
+ Why this issue only occurs on Jammy (and not on Noble or Resolute):
+
+ 1. Jammy builds and distributes a dedicated "disk-kvm.img":
+ In Jammy (22.04), cloud-image pipeline generates a dedicated lightweight VM
artifact (jammy-server-cloudimg-amd64-disk-kvm.img, as indexed on
cloud-images.ubuntu.com/jammy/current/ and Simplestreams).
+ Its package manifest (jammy-server-cloudimg-amd64-disk-kvm.manifest) confirms
that it is intentionally built with linux-image-kvm (5.15.0-*-kvm).
+ Because CONFIG_ISCSI_TARGET is disabled, iscsi_target_mod.ko is completely
absent in Jammy LXD VMs.
+
+ 2. Noble and Resolute no longer build "kvm" VM images:
+ Starting from 24.04 (Noble), Canonical deprecated the dedicated disk-kvm
build targets. As verifiable from cloud-images.ubuntu.com for noble and
resolute, there are no longer any disk-kvm artifacts published.
+ Instead, all cloud and LXD VM images consume the unified disk1.img
(server-cloudimg-amd64.img), which ships the standard generic kernel out of the
box (as confirmed by their official manifests):
+ - linux-image-6.8.0-*-generic (on Noble)
+ - linux-image-7.0.0-*-generic (on Resolute)
+ Because the standard generic kernel enables CONFIG_ISCSI_TARGET=m by default,
iscsi_target_mod.ko is natively present and loaded without issue on Noble and
Resolute.
+
+ Therefore, this regression is strictly confined to Jammy's LXD VM
+ environment, blocking proposed migration for reverse dependencies such
+ as open-iscsi (LP: #2147499).
[ Test Plan ]
1. On a testbed running a kernel without iscsi_target_mod support (e.g. Jammy
LXD VM running linux-kvm):
Run:
sudo debian/tests/run-ocft iscsi
Expected result before fix:
- Fails during setup with FATAL: Module iscsi_target_mod not found, exit
status 1.
+ Fails during setup with "FATAL: Module iscsi_target_mod not found",
exit status 1.
Expected result after fix:
Outputs:
SKIP: iscsi_target_mod module is not available in running kernel
<version>
- and exits 0 (clean skip / pass).
+ and exits 0 (clean skip / PASS).
2. On a testbed running a generic kernel where iscsi_target_mod is available
(e.g. linux-image-generic):
Run:
sudo debian/tests/run-ocft iscsi
Expected result:
Module loads and ocft test -v iscsi executes and passes normally.
[ Where problems could occur ]
The fix only touches the autopkgtest test runner script
`debian/tests/run-ocft`. It does not modify any binaries, packaged agent
scripts, or runtime behavior of resource-agents itself.
The only potential risk is if a regression in the iscsi resource agent is not
caught on environments lacking kernel module support; however, on generic
environments the test will continue to execute fully as before.
[ Other Info ]
- Relevant discussion in LP: #2147499 comment #24.
- Tag: block-proposed-jammy
+ - Relevant discussion in LP: #2147499 comment #24.
+ - Tag: block-proposed-jammy
+ - Proposed migration excuses tracking:
+
https://ubuntu-archive-team.ubuntu.com/proposed-migration/jammy/update_excuses.html#open-iscsi
+
https://ubuntu-archive-team.ubuntu.com/proposed-migration/noble/update_excuses.html#open-iscsi
+
https://ubuntu-archive-team.ubuntu.com/proposed-migration/resolute/update_excuses.html#open-iscsi
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https://bugs.launchpad.net/bugs/2170272
Title:
[SRU] resource-agents: autopkgtest iscsi fails on kernels without LIO
iSCSI target support (e.g. linux-kvm)
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