fix(hotplugd.socket): remove basic.target as dependency #5722
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In 62ace19 we moved cloud-init-hotplugd.socket earlier in boot, after cloud-config.target. But we didn't remove the dependencies added by default and this might conflict with other units producing non-solvable ordering cycles, see #2081124. Remove the default dependency on basic.target added by systemd. LP: #2081124
blackboxsw
reviewed
Sep 20, 2024
| @@ -5,6 +5,9 @@ | |||
| # Known bug with an enforcing SELinux policy: LP: #1936229 | |||
| [Unit] | |||
| Description=cloud-init hotplug hook socket | |||
| DefaultDependencies=no | |||
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Confirmed that image launches in virt-manager in Oracular Daily Desktop images from 20240916 with livecd-rootfs fix that we can see ordering cycle issues on Oracular too.
# Run on an Oracular custom image with proper cloud-init-network.service drop-in override from livecd-rootfs
+ cat /cdrom/.disk/info
Ubuntu 24.10 "Oracular Oriole" - Daily amd64 (20240916)+ echo Confirm expected livecd-rootfs dropin orders cloud-init-network.service After=NetworkManager.service
Confirm expected livecd-rootfs dropin orders cloud-init-network.service After=NetworkManager.service
+ cat /etc/systemd/system/cloud-init-network.service
# Based on cloud-init 24.3 for Desktop LiveCD
# Redact sysinit.target from Before, add After=NetworkManager*.service
# (LP: #2008952)
[Unit]
# https://cloudinit.readthedocs.io/en/latest/explanation/boot.html
Description=Cloud-init: Network Stage
DefaultDependencies=no
Wants=cloud-init-local.service
Wants=sshd-keygen.service
Wants=sshd.service
After=cloud-init-local.service
After=systemd-networkd-wait-online.service
After=networking.service
After=NetworkManager.service NetworkManager-wait-online.service
Before=network-online.target
Before=sshd-keygen.service
Before=sshd.service
Before=systemd-user-sessions.service
# Before=sysinit.target Redacted due to NetworkManager.service dbus depends
Before=shutdown.target
Conflicts=shutdown.target
ConditionPathExists=!/etc/cloud/cloud-init.disabled
ConditionKernelCommandLine=!cloud-init=disabled
ConditionEnvironment=!KERNEL_CMDLINE=cloud-init=disabled
[Service]
Type=oneshot
# This service is a shim which preserves systemd ordering while allowing a
# single Python process to run cloud-init's logic. This works by communicating
# with the cloud-init process over a unix socket to tell the process that this
# stage can start, and then wait on a return socket until the cloud-init
# process has completed this stage. The output from the return socket is piped
# into a shell so that the process can send a completion message (defaults to
# "done", otherwise includes an error message) and an exit code to systemd.
ExecStart=sh -c 'echo "start" | netcat -Uu -W1 /run/cloud-init/share/network.sock -s /run/cloud-init/share/network-return.sock | sh'
RemainAfterExit=yes
TimeoutSec=0
# Output needs to appear in instance console output
StandardOutput=journal+console
[Install]
WantedBy=cloud-init.target
+ systemctl show -p Before,After cloud-init-network.service --no-pager
Before=network-online.target sshd.service systemd-user-sessions.service sshd-keygen.service cloud-config.target shutdown.target
After=systemd-networkd-wait-online.service system.slice networking.service systemd-journald.socket NetworkManager.service cloud-init-local.service NetworkManager-wait-online.service
+ systemctl show -p Before,After cloud-init-hotplugd.socket --no-pager
Before=sockets.target shutdown.target cloud-init-hotplugd.service
After=-.mount system.slice cloud-config.target sysinit.target
+ systemctl show -p Before,After cloud-init-hotplugd.service --no-pager
Before=shutdown.target
After=systemd-journald.socket cloud-init-hotplugd.socket basic.target system.slice cloud-init.target sysinit.target
+ journalctl -b 0
+ grep ordering cycle
Sep 20 20:25:26 ubuntu systemd[1]: basic.target: Found ordering cycle on sockets.target/start
Sep 20 20:25:26 ubuntu systemd[1]: basic.target: Job sockets.target/start deleted to break ordering cycle starting with basic.target/start
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Also applied both livecd-rootfs fix and cloud-init fix from 5722
+ cat /cdrom/.disk/info
Ubuntu 24.10 "Oracular Oriole" - Daily amd64 (20240916)+ echo Confirm expected livecd-rootfs dropin orders cloud-init-network.service After=NetworkManager.service
Confirm expected livecd-rootfs dropin orders cloud-init-network.service After=NetworkManager.service
+ cat /etc/systemd/system/cloud-init-network.service
# Based on cloud-init 24.3 for Desktop LiveCD
# Redact sysinit.target from Before, add After=NetworkManager*.service
# (LP: #2008952)
[Unit]
# https://cloudinit.readthedocs.io/en/latest/explanation/boot.html
Description=Cloud-init: Network Stage
DefaultDependencies=no
Wants=cloud-init-local.service
Wants=sshd-keygen.service
Wants=sshd.service
After=cloud-init-local.service
After=systemd-networkd-wait-online.service
After=networking.service
After=NetworkManager.service NetworkManager-wait-online.service
Before=network-online.target
Before=sshd-keygen.service
Before=sshd.service
Before=systemd-user-sessions.service
# Before=sysinit.target Redacted due to NetworkManager.service dbus depends
Before=shutdown.target
Conflicts=shutdown.target
ConditionPathExists=!/etc/cloud/cloud-init.disabled
ConditionKernelCommandLine=!cloud-init=disabled
ConditionEnvironment=!KERNEL_CMDLINE=cloud-init=disabled
[Service]
Type=oneshot
# This service is a shim which preserves systemd ordering while allowing a
# single Python process to run cloud-init's logic. This works by communicating
# with the cloud-init process over a unix socket to tell the process that this
# stage can start, and then wait on a return socket until the cloud-init
# process has completed this stage. The output from the return socket is piped
# into a shell so that the process can send a completion message (defaults to
# "done", otherwise includes an error message) and an exit code to systemd.
ExecStart=sh -c 'echo "start" | netcat -Uu -W1 /run/cloud-init/share/network.sock -s /run/cloud-init/share/network-return.sock | sh'
RemainAfterExit=yes
TimeoutSec=0
# Output needs to appear in instance console output
StandardOutput=journal+console
[Install]
WantedBy=cloud-init.target
+ systemctl show -p Before,After cloud-init-network.service --no-pager
Before=sshd.service shutdown.target network-online.target systemd-user-sessions.service sshd-keygen.service cloud-config.target
After=NetworkManager.service systemd-journald.socket system.slice cloud-init-local.service networking.service NetworkManager-wait-online.service systemd-networkd-wait-online.service
+ systemctl show -p Before,After cloud-init-hotplugd.socket --no-pager
Before=shutdown.target cloud-init-hotplugd.service
After=-.mount cloud-config.target system.slice
+ systemctl show -p Before,After cloud-init-hotplugd.service --no-pager
Before=shutdown.target
After=cloud-init.target systemd-journald.socket basic.target cloud-init-hotplugd.socket sysinit.target system.slice
+ journalctl -b 0
+ grep ordering cycle
+ cat /lib/systemd/system/cloud-init-hotplugd.socket
# cloud-init-hotplugd.socket listens on the FIFO file
# /run/cloud-init/hook-hotplug-cmd which is created during a udev network
# add or remove event as processed by 90-cloud-init-hook-hotplug.rules.
# Known bug with an enforcing SELinux policy: LP: #1936229
[Unit]
Description=cloud-init hotplug hook socket
DefaultDependencies=no
Before=shutdown.target
Conflicts=shutdown.target
After=cloud-config.target
ConditionPathExists=!/etc/cloud/cloud-init.disabled
ConditionKernelCommandLine=!cloud-init=disabled
ConditionEnvironment=!KERNEL_CMDLINE=cloud-init=disabled
[Socket]
ListenFIFO=/run/cloud-init/hook-hotplug-cmd
[Install]
WantedBy=cloud-config.target
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No ordering cycles seen in ephemeral boot from journalctl in the second run, also we see sysinit.target dropped from hotplugd.socket due to the correction of DefaultDependencies=no
+ systemctl show -p Before,After cloud-init-hotplugd.socket --no-pager
Before=shutdown.target cloud-init-hotplugd.service
After=-.mount cloud-config.target system.slice
blackboxsw
approved these changes
Sep 20, 2024
| @@ -5,6 +5,9 @@ | |||
| # Known bug with an enforcing SELinux policy: LP: #1936229 | |||
| [Unit] | |||
| Description=cloud-init hotplug hook socket | |||
| DefaultDependencies=no | |||
There was a problem hiding this comment.
No ordering cycles seen in ephemeral boot from journalctl in the second run, also we see sysinit.target dropped from hotplugd.socket due to the correction of DefaultDependencies=no
+ systemctl show -p Before,After cloud-init-hotplugd.socket --no-pager
Before=shutdown.target cloud-init-hotplugd.service
After=-.mount cloud-config.target system.slice
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Proposed Commit Message
Additional Context
I have manually tested this on and image produced by https://cdimage.ubuntu.com/noble/daily-live/20240920/, modifying the target system prior to first-booting.
Test Steps
Merge type