[Bug 1882986] Re: open-iscsi is slowing down the boot process

[Zakhar]

As explained by Christian on #4, I did further tests:

- Disables only open-iscsi
- To be sure, I moved out of the way what was in /etc/iscsi/nodes which is now empty
- To be sure, did the same with /etc/iscsi/send-targets
- To be extra sure, even removed those directory

And when I boot my machine, iscsid.service is still starting although it
is supposed to be "socket activated".

I also removed the 2 lines in iscsid.service:

#[Install]
# WantedBy=sysinit.target

Because according to http://0pointer.de/blog/projects/socket-activation.html
this also unconditionally starts iscsid.service


Here is the result after all that:
$ systemctl status open-iscsi.service iscsid.service iscsid.socket 
● open-iscsi.service - Login to default iSCSI targets
     Loaded: loaded (/lib/systemd/system/open-iscsi.service; disabled; vendor preset: enabled)
     Active: inactive (dead)
       Docs: man:iscsiadm(8)
             man:iscsid(8)

● iscsid.service - iSCSI initiator daemon (iscsid)
     Loaded: loaded (/lib/systemd/system/iscsid.service; enabled; vendor preset: enabled)
     Active: active (running) since Sat 2020-06-20 12:13:55 CEST; 16s ago
TriggeredBy: ● iscsid.socket
       Docs: man:iscsid(8)
    Process: 1430 ExecStartPre=/lib/open-iscsi/startup-checks.sh (code=exited, status=0/SUCCESS)
    Process: 1437 ExecStart=/sbin/iscsid (code=exited, status=0/SUCCESS)
   Main PID: 1440 (iscsid)
      Tasks: 2 (limit: 38305)
     Memory: 3.6M
     CGroup: /system.slice/iscsid.service
             ├─1439 /sbin/iscsid
             └─1440 /sbin/iscsid

juin 20 12:13:55 alain-HTPC systemd[1]: Starting iSCSI initiator daemon (iscsid)...
juin 20 12:13:55 alain-HTPC iscsid[1437]: iSCSI logger with pid=1439 started!
juin 20 12:13:55 alain-HTPC systemd[1]: iscsid.service: Failed to parse PID from file /run/iscsid.pid: Invalid argument
juin 20 12:13:55 alain-HTPC systemd[1]: Started iSCSI initiator daemon (iscsid).
juin 20 12:13:56 alain-HTPC iscsid[1439]: iSCSI daemon with pid=1440 started!

● iscsid.socket - Open-iSCSI iscsid Socket
     Loaded: loaded (/lib/systemd/system/iscsid.socket; enabled; vendor preset: enabled)
     Active: active (running) since Sat 2020-06-20 12:13:46 CEST; 25s ago
   Triggers: ● iscsid.service
       Docs: man:iscsid(8)
             man:iscsiadm(8)
     Listen: @ISCSIADM_ABSTRACT_NAMESPACE (Stream)
     CGroup: /system.slice/iscsid.socket

juin 20 12:13:46 alain-HTPC systemd[1]: Listening on Open-iSCSI iscsid
Socket.


And (as root)
# tree /etc/iscsi/
/etc/iscsi/
├── initiatorname.iscsi
└── iscsid.conf

0 directories, 2 files


According to Christian's explanation at  #4

- open-iscsi now cannot trigger the socket since it has been disabled
(see above) and also there are now no nodes or send-targets

- iscsid is still started, although the "database" (in fact the tree
directory under /etc/iscsi) is completely empty, and the "install"
clause has been removed from the service.



Where does this come from?

Is it a bug or some other "traces" I might have in my configuration that
make iscsid start?


** Changed in: open-iscsi (Ubuntu)
       Status: Invalid => New

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https://bugs.launchpad.net/bugs/1882986

Title:
  open-iscsi is slowing down the boot process

Status in open-iscsi package in Ubuntu:
  New

Bug description:
  This is not a bug, but rather an "optimisation" request.

  (Probably set this as "enhancement request" + Low)

  Apparently, the package is assuming the user will need some iscsi
  mounts for his session, and is putting dependencies in the systemd
  services/targets which effects are to delay "graphical.target" to
  after the point when the network is online.

  A great job has been done by Ubuntu so that the O.S. appears to be
  "snappy" from the boot, and when the session is in "auto-login", it
  really makes a great difference and a good feeling of the system being
  very quick.

  This assumption of open-iscsi sort of ruins that effort.

  As an example, on my PC the graphical target is delayed 10 seconds
  more (was 22 seconds and is now 32). The impression is not as good and
  the system feels "slow again" (although it is just a feeling!)

  
  Step to reproduced (you don't even need to have iscsi LUNs to to so, just install the package!)
  - Start from a clean 20.04, boot up and issue: systemd-analyze
  - Now install open-iscsi, reboot and issue again: systemd-analyze

  The result will probably be a big impact on "graphical target",
  although total time does not change a lot.


  My usage is not needing iscsi targets for my session.
  I have a NAS with iscsi LUNs, and when I need those mounts, I just start them with a command.

  sudo iscsiadm -m node -l

  Then Gnome recognises a new disk has been inserted and does an "auto mount".
  This command works whether the service was started or not.


  This wrong assumption is easily fixed in my case with this command:

  
  sudo systemctl disable iscsid.socket iscsid.service open-iscsi.service

  
  Then, at the next reboot the graphical target is snappy again, and does not have to wait for network-online and remote-fs targets.


  I don't know what can be done to cope with both situations : those who
  need an iscsi target mounted for their session, and those who don't...
  but I guess the philosophy now should be to assume the user does not
  need such targets, and don't put dependencies that delay the snappy
  boot process.

  For those who need those mounted remote fs for their session, detailed
  help on how to enable iscsi services at startup should be provided.

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