Hi Christian On Mon, Feb 24, 2020 at 1:51 PM Christian Ehrhardt < [email protected]> wrote:
> > > On Tue, Feb 18, 2020 at 3:23 AM Rafael David Tinoco < > [email protected]> wrote: > >> Hello all, >> >> I have always used TGT project, despite its bad performance, as iSCSI >> target in Linux, offering iSCSI luns for HA clusters. It was known to me >> that TGT was *not* the best iSCSI target supported in Linux, being LIO >> the chosen project for that (now called TCM: >> https://www.kernel.org/doc/Documentation/target/tcmu-design.txt). >> >> In a recent need, I needed SCSI 3 reservations in those SCSI volumes, to >> test and enable fence_scsi agent, and was getting unclear errors when >> trying to reserve the LUNs. >> >> The following commands - that would register a reservation key, reserve >> a lun, release the reservation and unregister the key - don't work when >> using TGT iSCSI luns with open-scsi and iscsid tool/service. >> >> $ sg_persist -r /dev/sda >> $ sg_persist --out --register --param-sark=123abc /dev/sda >> $ sg_persist --out --reserve --param-rk=123abc --prout-type=5 /dev/sda >> >> prout-type = 5 -> executes SCSI PERSISTENT RESERVE OUT (5Fh) command >> with the PREEMPT AND ABORT (05h) service >> >> (https://bugs.launchpad.net/ubuntu/+source/tgt/+bug/1863688) >> >> $ sg_persist --out --release --param-rk=123abc --prout-type=5 /dev/sda >> $ sg_persist --out --register --param-rk=123abc /dev/sda >> >> With that, its impossible to fence iSCSI luns using corosync/pacemaker >> clusters. >> >> TCM (or LIO) project fully supports fencing and several other iSCSI >> features. It also supports userland backends that can extend backing >> devices so it supports: qcow2, ceph, etc... >> >> Despite being HA only or not, this use case is actually being used in >> this email to show the need to have a tool that configures kernel TCM >> (or LIO) capability as a supported tool (at least IMO). >> >> I have found a recent previous MIR attempt of 1/3 of what is needed: >> >> https://bugs.launchpad.net/ubuntu/+source/python-rtslib-fb/+bug/1854362 >> >> But, afaict, we would need MIRs for: >> >> - python3-configshell-fb >> - python3-rtslib-fb >> - targetcli-fb >> >> To have the "targetcli" tool in [main]. Upstream projects are hosted >> together with open-iscsi repository, suggesting that they are actively >> maintained and in good shape. >> >> Has this ever been discussed ? It looks to me something we could/should >> have in 20.04. Thoughts ? >> > > IIRC cinder-volume was the last bit holding back a switch. > $ reverse-depends -r focal tgt > Reverse-Depends > =============== > * cinder-volume > * tgt-rbd [amd64 arm64 armhf ppc64el s390x] > > And at least cinder-volume is in main. > So we'd have to have that changed to make the switch (as we should have > only one supported iSCSI in main). > > IIRC that was also the reason we waited on last time and checking the bug > [1] confirms similar thoughts. > It seems you are working with jamespage already to make that switch happen. > I have a branch prepared for cinder to switch over the default iSCSI target helper to LIO. > > Also security needs to process all the extra packages in just three days - > unlikely right? > > IMHO while I agree It would be nice for 20.04 but if it is not doable in > time due to all these constraints it is ok as well to "just" target 20.10 > with it. > Please be on the same page with @Josh Powers <[email protected]> on > this as this will be quite an intense ride to be squeezed into 20.04. > > P.S. FYI another reason in the past was maas but they are in a snap now > and use their "own" tgt, so no dependency to consider anymore. > P.P.S. have you asked (TBH I'd not know where) if some of our primary > charms might depend on tgt? > > [1]: > https://bugs.launchpad.net/ubuntu/+source/python-rtslib-fb/+bug/1854362/comments/17 > > > Thanks! >> >> Rafael >> >> -- >> ubuntu-server mailing list >> [email protected] >> https://lists.ubuntu.com/mailman/listinfo/ubuntu-server >> More info: https://wiki.ubuntu.com/ServerTeam > > > > -- > Christian Ehrhardt > Staff Engineer, Ubuntu Server > Canonical Ltd > -- > ubuntu-server mailing list > [email protected] > https://lists.ubuntu.com/mailman/listinfo/ubuntu-server > More info: https://wiki.ubuntu.com/ServerTeam
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