[systemd-devel] socket: Failed to queue service startup job: Transport endpoint is not connected

[Alec Moskvin]

A few days ago I tried to ssh into one of my boxes (which was using
socket-activated per-connection ssh) but got connection refused. Luckily
I had another ssh session open. In the journal, the only relevant thing
logged was:

  systemd[1]: sshd.socket: Failed to queue service startup job (Maybe the service file is missing or not a template unit?): Transport endpoint is not connected
  systemd[1]: sshd.socket: Failed with result 'resources'.

I started the socket back up and could connect again. The system had
been mostly idle and there were no upgrades since it booted up 2 days
earlier. The previous ssh login attempt was 4 hours before.

Any idea what could have caused this?

In the process of researching the issue I discovered the "trigger limit"
but that looks very different (with result 'trigger-limit-hit').

Thanks,
Alec


$ systemctl cat sshd.socket
# /lib/systemd/system/sshd.socket
[Unit]
Description=OpenSSH Server Socket
Conflicts=sshd.service

[Socket]
ListenStream=22
Accept=yes

[Install]
WantedBy=sockets.target

$ systemctl cat sshd at .service
# /lib/systemd/system/sshd at .service
[Unit]
Description=OpenSSH per-connection server daemon
After=syslog.target auditd.service

[Service]
ExecStart=-/usr/sbin/sshd -i -e
StandardInput=socket
StandardError=journal

$ systemctl --version
systemd 246 (246)
+PAM -AUDIT -SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP -LIBCRYPTSETUP +GCRYPT -GNUTLS +ACL -XZ -LZ4 +ZSTD +SECCOMP +BLKID -ELFUTILS -KMOD +IDN2 -IDN +PCRE2 default-hierarchy=unified