我创建了一个 systemd 服务，它使用 ssh 回拨中央服务器。
[Unit]
Description=Create a tunnel in the cloud back to SSH on this machine
After=network-online.target
[Service]
User=mindhive
ExecStart=/usr/bin/ssh -o ServerAliveInterval=20 -o ServerAliveCountMax=3 -o ExitOnForwardFailure=yes -o StrictHostKeyChecking=no -i /home/mindhive/.ssh/tunnel.id_rsa -N -T -R1822:localhost:22 tunnel@***server-hidden***
RestartSec=60
Restart=always
[Install]
WantedBy=multi-user.target
我在我们的许多服务器上都使用它，所有服务器都是 Ubuntu 16.04。突然其中一个停止了工作。我可以从日志（下面）中看到它与.ssh对 homedir 的访问有关。该服务设置为Restart=always和RestartSec=60，因此重新启动后，它会每分钟再次尝试，但每次都会失败。但是，如果我手动sudo systemctl restart ssh-tunnel.service启动就没有问题。
您可以从下面的日志（输出journalctl）中看到它失败并重试，但在 14:54:10 手动启动时它启动正常。
到目前为止，通过谷歌搜索，我已经尝试将 和 都添加WorkingDirectory=~到ProtectHome=off服务中。但这没有什么区别。
ssh为什么重启后由 systemd 启动时无法访问用户的 homedir，但通过 手动启动却可以systemctl？
-- Reboot --
Feb 24 14:50:12 ***servername*** systemd[1]: Started Create a tunnel in the cloud back to SSH on this machine.
Feb 24 14:50:12 ***servername*** ssh[1252]: Warning: Identity file /home/mindhive/.ssh/tunnel.id_rsa not accessible: No such file or directory.
Feb 24 14:50:13 ***servername*** ssh[1252]: Could not create directory '/home/mindhive/.ssh'.
Feb 24 14:50:14 ***servername*** ssh[1252]: Failed to add the host to the list of known hosts (/home/mindhive/.ssh/known_hosts).
Feb 24 14:50:15 ***servername*** systemd[1]: ssh-tunnel.service: Main process exited, code=exited, status=255/n/a
Feb 24 14:50:15 ***servername*** systemd[1]: ssh-tunnel.service: Unit entered failed state.
Feb 24 14:50:15 ***servername*** systemd[1]: ssh-tunnel.service: Failed with result 'exit-code'.
Feb 24 14:51:15 ***servername*** systemd[1]: ssh-tunnel.service: Service hold-off time over, scheduling restart.
Feb 24 14:51:15 ***servername*** systemd[1]: Stopped Create a tunnel in the cloud back to SSH on this machine.
Feb 24 14:51:15 ***servername*** systemd[1]: Started Create a tunnel in the cloud back to SSH on this machine.
Feb 24 14:51:15 ***servername*** ssh[1367]: Warning: Identity file /home/mindhive/.ssh/tunnel.id_rsa not accessible: No such file or directory.
Feb 24 14:51:16 ***servername*** ssh[1367]: Could not create directory '/home/mindhive/.ssh'.
Feb 24 14:51:17 ***servername*** ssh[1367]: Failed to add the host to the list of known hosts (/home/mindhive/.ssh/known_hosts).
Feb 24 14:51:18 ***servername*** systemd[1]: ssh-tunnel.service: Main process exited, code=exited, status=255/n/a
Feb 24 14:51:18 ***servername*** systemd[1]: ssh-tunnel.service: Unit entered failed state.
Feb 24 14:51:18 ***servername*** systemd[1]: ssh-tunnel.service: Failed with result 'exit-code'.
Feb 24 14:52:18 ***servername*** systemd[1]: ssh-tunnel.service: Service hold-off time over, scheduling restart.
Feb 24 14:52:18 ***servername*** systemd[1]: Stopped Create a tunnel in the cloud back to SSH on this machine.
Feb 24 14:52:18 ***servername*** systemd[1]: Started Create a tunnel in the cloud back to SSH on this machine.
Feb 24 14:52:18 ***servername*** ssh[1370]: Warning: Identity file /home/mindhive/.ssh/tunnel.id_rsa not accessible: No such file or directory.
Feb 24 14:52:19 ***servername*** ssh[1370]: Could not create directory '/home/mindhive/.ssh'.
Feb 24 14:52:20 ***servername*** ssh[1370]: Failed to add the host to the list of known hosts (/home/mindhive/.ssh/known_hosts).
Feb 24 14:52:20 ***servername*** systemd[1]: ssh-tunnel.service: Main process exited, code=exited, status=255/n/a
Feb 24 14:52:20 ***servername*** systemd[1]: ssh-tunnel.service: Unit entered failed state.
Feb 24 14:52:20 ***servername*** systemd[1]: ssh-tunnel.service: Failed with result 'exit-code'.
Feb 24 14:53:21 ***servername*** systemd[1]: ssh-tunnel.service: Service hold-off time over, scheduling restart.
Feb 24 14:53:21 ***servername*** systemd[1]: Stopped Create a tunnel in the cloud back to SSH on this machine.
Feb 24 14:53:21 ***servername*** systemd[1]: Started Create a tunnel in the cloud back to SSH on this machine.
Feb 24 14:53:21 ***servername*** ssh[1393]: Warning: Identity file /home/mindhive/.ssh/tunnel.id_rsa not accessible: No such file or directory.
Feb 24 14:53:21 ***servername*** ssh[1393]: Could not create directory '/home/mindhive/.ssh'.
Feb 24 14:53:22 ***servername*** ssh[1393]: Failed to add the host to the list of known hosts (/home/mindhive/.ssh/known_hosts).
Feb 24 14:53:23 ***servername*** systemd[1]: ssh-tunnel.service: Main process exited, code=exited, status=255/n/a
Feb 24 14:53:23 ***servername*** systemd[1]: ssh-tunnel.service: Unit entered failed state.
Feb 24 14:53:23 ***servername*** systemd[1]: ssh-tunnel.service: Failed with result 'exit-code'.
Feb 24 14:54:10 ***servername*** systemd[1]: Stopped Create a tunnel in the cloud back to SSH on this machine.
Feb 24 14:54:10 ***servername*** systemd[1]: Started Create a tunnel in the cloud back to SSH on this machine.
答案1
好的。最终我自己设法弄清楚了。问题是 Ubuntu 已安装加密的主目录。因此，这就是为什么服务无法访问其中的文件，~/.ssh直到我登录（因此解密主目录）并重新启动它。
删除加密并不容易。我发现这些说明最好的。