Re: [systemd-devel] Help: Local and Remote targets
On Di, 20.08.19 15:26, Tony Rodriguez (unixpro1...@gmail.com) wrote: > I modified systemd-219 functionality to meet a custom requirement for > detecting filesystems/devices that use iscsi without using the _netdev > keyword in /etc/fstab. It is a strict requirement regarding not using > _netdev that I have no control over. However, I am stuck. I am sorry, but "_netdev" is the method we use for ordering mounts against networking. It's what it does, it's the all that it is. What you are asking for is like asking for "I'd like to hammer this nail into a wall, but I really don't want to use a hammer." I mean, sure you can use other stuff, but the hammer is what is what the tool is called you hammer stuff into walls with, so that's what you use... > From my understanding, src/fstab-generator.c is used to determine LOCAL-FS > and REMOTE-FS. I have modified fstab-generator.c to search for iscsi udev > devices which works, provided the system is already fully booted > (typical Generators are run during early boot already, they may not have dependencies on system state and just convert configuration from arbitrary external formats to units files as understood by systemd. If you do IPC or generate different units based on dnymaically changing system state you will run into trouble, you are misusing generators, and this is explicitly documented. > multi-user state type of thing). I can also find /dev/disk/ block devices > including iscsi devices using my logic within fstab-generator.c. The > problem is when the system reboots, it appears systemd using the same > fstab-generator logic that I implemented is unable to detect any iscsi > devices. After doing some research, it appears normal systemd behavior is > to mount / and /usr then invoke fstab-generator.c to determine if a given > filesystem in /etc/fstab should be a local or remote target. Well, ISCSI is usually set up later during boot and generators run very early, hence if you look for already active iscsi devices in generators you are not going to find any. Did you read the docs about generators? Please have a look at these notes: https://www.freedesktop.org/software/systemd/man/systemd.generator.html#Notes%20about%20writing%20generators > The problem is I have no way to tell if a given iscsi filesystem/device > specified in /etc/fstab (without the _netdev keyord ) is local/remote during > the booting state. Mainly because devices are not yet populated in There's an easy way to denote that, it's called _netdev, it's what it does. > /dev/disk or udev. Is there a way I can determine if a filesystem/mount > point/device specified in /etc/fstab is local or remote without the _netdev > or fstype (which handles nfs, etc) keywords within fstab-generator.c? If > checking udev and /dev/disk are not possible within fstab-generator.c, > because such devices are not yet populated, then what should I modify within > the systemd source so I can determine such local/remote targets myself and > pass it to fstab-generator.c (especially when the system is in that / and > /usr mounting state and udev devices are not yet populated? Use _netdev, that's what it is for. You may use "x-systemd.after=remote-fs-pre.target" as mount option to emulate some of the effect of _netdev, but that does more. Anyway, sorry for the disappointing answer, but your quest makes little sense to me. What you are looking for is _netdev. If you don't want to use that you created yourself a problem you have to solve yourself. Sorr, Lennart -- Lennart Poettering, Berlin ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Help: Local and Remote targets
Understood but I don't have to worry about iscsi offloading for now. Some theories I have to attack the problem but each has a problem and may be complex. 1) Since I can obtain udev/disk information when the system is in a multi-user already booted stated. Check for "iscsi" devices and filesystems then create a file on "/" that has the device id and specify it as an iscsi device. When the system reboots then check for that file, if it exists set state to REMOTE-FS target within fstab-generator.c Problem: I will have to manage create/remove such files within systemd especially if contents within /etc/fstab are manually modified by the user. Where would be the best place to put such logic within systemd source? 2) Boot the system mounting only "/" and "/usr" and defer fstab-generatoration until the system is booted. Then find a way to manually re-start fstab-generation after iscsi/network are operational. After that restart systemd. Problem: Unsure if this is reasonable. Wondering if doing so may introduce some kind of side effect issues regarding mounting and other services. Note: Really hoping for an easier way instead of trying to implement points (1) or (2) Tony On 8/20/19 3:33 PM, Rick Beldin wrote: This might be problematic. What will you do with iscsi devices that support iscsi offload? Those are typically completely invisible to the OS and just appear as another HBA. On 8/20/19 3:26 PM, Tony Rodriguez wrote: I modified systemd-219 functionality to meet a custom requirement for detecting filesystems/devices that use iscsi without using the _netdev keyword in /etc/fstab. It is a strict requirement regarding not using _netdev that I have no control over. However, I am stuck. From my understanding, src/fstab-generator.c is used to determine LOCAL-FS and REMOTE-FS. I have modified fstab-generator.c to search for iscsi udev devices which works, provided the system is already fully booted (typical multi-user state type of thing). I can also find /dev/disk/ block devices including iscsi devices using my logic within fstab-generator.c. The problem is when the system reboots, it appears systemd using the same fstab-generator logic that I implemented is unable to detect any iscsi devices. After doing some research, it appears normal systemd behavior is to mount / and /usr then invoke fstab-generator.c to determine if a given filesystem in /etc/fstab should be a local or remote target. The problem is I have no way to tell if a given iscsi filesystem/device specified in /etc/fstab (without the _netdev keyord ) is local/remote during the booting state. Mainly because devices are not yet populated in /dev/disk or udev. Is there a way I can determine if a filesystem/mount point/device specified in /etc/fstab is local or remote without the _netdev or fstype (which handles nfs, etc) keywords within fstab-generator.c? If checking udev and /dev/disk are not possible within fstab-generator.c, because such devices are not yet populated, then what should I modify within the systemd source so I can determine such local/remote targets myself and pass it to fstab-generator.c (especially when the system is in that / and /usr mounting state and udev devices are not yet populated? Thanks, Tony ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
Re: [systemd-devel] Help: Local and Remote targets
This might be problematic. What will you do with iscsi devices that support iscsi offload? Those are typically completely invisible to the OS and just appear as another HBA. On 8/20/19 3:26 PM, Tony Rodriguez wrote: > I modified systemd-219 functionality to meet a custom requirement for > detecting filesystems/devices that use iscsi without using the _netdev keyword > in /etc/fstab. It is a strict requirement regarding not using _netdev that I > have no control over. However, I am stuck. > > From my understanding, src/fstab-generator.c is used to determine LOCAL-FS and > REMOTE-FS. I have modified fstab-generator.c to search for iscsi udev devices > which works, provided the system is already fully booted (typical multi-user > state type of thing). I can also find /dev/disk/ block devices including > iscsi devices using my logic within fstab-generator.c. The problem is when > the system reboots, it appears systemd using the same fstab-generator logic > that I implemented is unable to detect any iscsi devices. After doing some > research, it appears normal systemd behavior is to mount / and /usr then > invoke fstab-generator.c to determine if a given filesystem in /etc/fstab > should be a local or remote target. > > The problem is I have no way to tell if a given iscsi filesystem/device > specified in /etc/fstab (without the _netdev keyord ) is local/remote during > the booting state. Mainly because devices are not yet populated in /dev/disk > or udev. Is there a way I can determine if a filesystem/mount point/device > specified in /etc/fstab is local or remote without the _netdev or fstype > (which handles nfs, etc) keywords within fstab-generator.c? If checking udev > and /dev/disk are not possible within fstab-generator.c, because such devices > are not yet populated, then what should I modify within the systemd source so > I can determine such local/remote targets myself and pass it to > fstab-generator.c (especially when the system is in that / and /usr mounting > state and udev devices are not yet populated? > > Thanks, > Tony > ___ > systemd-devel mailing list > systemd-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/systemd-devel > -- Rick Beldin HPE Master Technologist, ERT HPE Pointnext Tel: +1 470 2129073 Email: rick.bel...@hpe.com Physical: 8000 Foothills Blvd. | Roseville, CA 95747 Hewlett Packard Enterprise ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
[systemd-devel] Help: Local and Remote targets
I modified systemd-219 functionality to meet a custom requirement for detecting filesystems/devices that use iscsi without using the _netdev keyword in /etc/fstab. It is a strict requirement regarding not using _netdev that I have no control over. However, I am stuck. From my understanding, src/fstab-generator.c is used to determine LOCAL-FS and REMOTE-FS. I have modified fstab-generator.c to search for iscsi udev devices which works, provided the system is already fully booted (typical multi-user state type of thing). I can also find /dev/disk/ block devices including iscsi devices using my logic within fstab-generator.c. The problem is when the system reboots, it appears systemd using the same fstab-generator logic that I implemented is unable to detect any iscsi devices. After doing some research, it appears normal systemd behavior is to mount / and /usr then invoke fstab-generator.c to determine if a given filesystem in /etc/fstab should be a local or remote target. The problem is I have no way to tell if a given iscsi filesystem/device specified in /etc/fstab (without the _netdev keyord ) is local/remote during the booting state. Mainly because devices are not yet populated in /dev/disk or udev. Is there a way I can determine if a filesystem/mount point/device specified in /etc/fstab is local or remote without the _netdev or fstype (which handles nfs, etc) keywords within fstab-generator.c? If checking udev and /dev/disk are not possible within fstab-generator.c, because such devices are not yet populated, then what should I modify within the systemd source so I can determine such local/remote targets myself and pass it to fstab-generator.c (especially when the system is in that / and /usr mounting state and udev devices are not yet populated? Thanks, Tony ___ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
