ssh 登录缓慢 - org.freedesktop.login1 的激活超时

Question

在我的一台服务器上，我注意到 SSH 登录确实有延迟。

使用 ssh -vvv 选项连接延迟发生在 debug1: Entering interactive session.

连接摘录：

debug1: Authentication succeeded (publickey).
Authenticated to IP_REDACTED ([IP_REDACTED]:22).
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug2: callback start
debug2: fd 3 setting TCP_NODELAY
debug3: packet_set_tos: set IP_TOS 0x10
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 1

使用此处概述的方法，我生成了 strace 输出并注意到14:09:53.676004 ppoll([{fd=5, events=POLLIN}], 1, {24, 999645000}, NULL, 8) = 1 ([{fd=5, revents=POLLIN}], left {0, 0}) <25.020764>需要 25 秒的行。

strace 输出的摘录：

14:09:53.675567 clock_gettime(CLOCK_MONOTONIC, {4662549, 999741404}) = 0 <0.000024>
14:09:53.675651 recvmsg(5, {msg_name(0)=NULL, msg_iov(1)=[{"l\4\1\1\n\0\0\0\2\0\0\0\215\0\0\0\1\1o\0\25\0\0\0", 24}], msg_controll
en=0, msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) = 24 <0.000024>
14:09:53.675744 recvmsg(5, {msg_name(0)=NULL, msg_iov(1)=[{"/org/freedesktop/DBus\0\0\0\2\1s\0\24\0\0\0"..., 146}], msg_controllen
=0, msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) = 146 <0.000025>
14:09:53.675842 recvmsg(5, 0x7ffe0ff1dfa0, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) = -1 EAGAIN (Resource temporarily unavailab
le) <0.000023>
14:09:53.675925 clock_gettime(CLOCK_MONOTONIC, {4662550, 96075}) = 0 <0.000024>
14:09:53.676004 ppoll([{fd=5, events=POLLIN}], 1, {24, 999645000}, NULL, 8) = 1 ([{fd=5, revents=POLLIN}], left {0, 0}) <25.020764>
14:10:18.696865 recvmsg(5, {msg_name(0)=NULL, msg_iov(1)=[{"l\3\1\0013\0\0\0\3\0\0\0m\0\0\0\6\1s\0\5\0\0\0", 24}], msg_controllen=0,     msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) = 24 <0.000017>
14:10:18.696944 recvmsg(5, {msg_name(0)=NULL, msg_iov(1)=[{":1.10\0\0\0\4\1s\0#\0\0\0org.freedesktop."..., 155}], msg_controllen=0, msg_flags=MSG_CMSG_CLOEXEC}, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) = 155 <0.000018>

我在相关时间注意到身份验证日志中的一个条目：

Jul 21 14:10:18 click sshd[8165]: pam_systemd(sshd:session): Failed to create session: Activation of org.freedesktop.login1 timed out

不太了解它试图轮询什么以及为什么它现在在这个特定的服务器上需要 25 秒。

该journalctl -u systemd-logind命令显示

Jul 20 11:33:06 click systemd-logind[19415]: Failed to abandon session scope: Transport endpoint is not connected
Jul 21 05:04:54 myhost systemd[1]: Started Login Service.
Jul 21 12:15:30 myhost systemd[1]: Started Login Service.
Jul 21 12:17:04 myhost systemd[1]: Started Login Service.
Jul 21 12:49:55 myhost systemd[1]: Started Login Service.
Jul 21 13:57:05 myhost systemd[1]: Started Login Service.
Jul 21 13:58:49 myhost systemd[1]: Started Login Service.
Jul 21 14:01:55 myhost systemd[1]: Started Login Service.
Jul 21 14:08:32 myhost systemd[1]: Started Login Service.
Jul 21 14:09:53 myhost systemd[1]: Started Login Service.
Jul 21 14:19:08 myhost systemd[1]: Started Login Service.
Jul 21 14:21:26 myhost systemd[1]: Started Login Service.
Jul 21 14:22:37 myhost systemd[1]: Started Login Service.
Jul 21 14:25:20 myhost systemd[1]: Started Login Service.
Jul 21 14:30:27 myhost systemd[1]: Started Login Service.
Jul 21 15:02:56 myhost systemd[1]: Started Login Service.

发出命令systemctl restart systemd-logind.service修复它（现在可能）。

Activation of org.freedesktop.login1它提到的是什么？有没有办法可以防止将来重新启动登录？我希望随着时间的推移，我管理的其他服务器都会遇到这个问题。

刚刚注意到这开始发生在另一台服务器上。

$ sudo service systemd-logind status

? systemd-logind.service - Login Service
   Loaded: loaded (/lib/systemd/system/systemd-logind.service; static)
   Active: active (running) since Tue 2015-06-16 14:10:57 BST; 1 months 12 days ago
     Docs: man:systemd-logind.service(8)
           man:logind.conf(5)
           http://www.freedesktop.org/wiki/Software/systemd/logind
           http://www.freedesktop.org/wiki/Software/systemd/multiseat
 Main PID: 1701 (systemd-logind)
   Status: "Processing requests..."
   CGroup: /system.slice/systemd-logind.service
           ??1701 /lib/systemd/systemd-logind

Jul 28 13:16:21 myhost systemd[1]: Started Login Service.
Jul 28 13:16:47 myhost systemd[1]: Started Login Service.
Jul 28 16:09:23 myhost systemd[1]: Started Login Service.
Jul 28 16:09:49 myhost systemd[1]: Started Login Service.
Jul 28 16:10:15 myhost systemd[1]: Started Login Service.
Jul 28 16:10:41 myhost systemd[1]: Started Login Service.
Jul 28 22:50:19 myhost systemd[1]: Started Login Service.
Jul 29 05:00:15 myhost systemd[1]: Started Login Service.
Jul 29 11:00:20 myhost systemd[1]: Started Login Service.
Jul 29 11:09:56 myhost systemd[1]: Started Login Service.

编辑 - 扩展journalctl输出。

EDIT2 - 当注意到这在另一台服务器上启动时，按照评论中的建议添加了 systemd-logind 状态。

更新 - 这开始发生在我的其他 Jessie 服务器上。我是唯一一个遇到这种情况的人吗？除了重新启动 systemd-logind 之外，必须有一些修复，有人有什么想法吗？

有一个关于这个770135的 Debian 错误报告。

Answer 1

当 dbus 重新启动时会发生这种情况，但 systemd-logind 未重新启动。只需执行以下操作：

systemctl restart systemd-logind

解决方案来自这里：https : //major.io/2015/07/27/very-slow-ssh-logins-on-fedora-22/