[VCL-992] ext_sshd service occasionally fails to restart under systemd

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Fix Version/s: 2.5
• Assignee: Andrew Kurth
• Reporter: Andrew Kurth
• Created: 22/Sep/16 13:59
• Updated: 31/Mar/17 16:22
• Resolved: 31/Mar/17 16:22

Description

I have seen the ext_sshd service fail to start/restart when controlled by systemd on Ubuntu 16. When this occurs, the status of the service shows:

root@<hostname>:/etc/ssh# service ext_sshd status
* ext_sshd.service - OpenBSD Secure Shell server
   Loaded: loaded (/lib/systemd/system/ext_sshd.service; enabled; vendor preset: enabled)
   Active: inactive (dead) since Wed 2016-09-21 16:37:56 EDT; 17h ago
  Process: 5515 ExecStart=/usr/sbin/sshd -D -f /etc/ssh/external_sshd_config (code=exited, status=0/SUCCESS)
 Main PID: 5515 (code=exited, status=0/SUCCESS)

Sep 21 16:37:56 <hostname> systemd[1]: Starting OpenBSD Secure Shell server...
Sep 21 16:37:56 <hostname> sshd[5515]: Server listening on <IP address> port 22.
Sep 21 16:37:56 <hostname> systemd[1]: Started OpenBSD Secure Shell server.
Sep 21 16:37:56 <hostname> systemd[1]: Stopping OpenBSD Secure Shell server...
Sep 21 16:37:56 <hostname> systemd[1]: Stopped OpenBSD Secure Shell server.
Sep 21 16:37:56 <hostname> systemd[1]: ext_sshd.service: Start request repeated too quickly.
Sep 21 16:37:56 <hostname> systemd[1]: Failed to start OpenBSD Secure Shell server.
Sep 21 16:37:56 <hostname> systemd[1]: Stopped OpenBSD Secure Shell server.
Sep 21 16:37:56 <hostname> systemd[1]: ext_sshd.service: Start request repeated too quickly.
Sep 21 16:37:56 <hostname> systemd[1]: Failed to start OpenBSD Secure Shell server.

Users cannot connect:

ssh: connect to host <IP address> port 22: Connection refused

Adding these lines under the [Service] section in /lib/systemd/system/ext_sshd.service may prevent this from occurring:

Restart=on-failure
RestartSec=3s

I don't know for sure if this alone will fix the problem. There may be additional options that could be added to the file. (man systemd.service)

Issue Links

• is duplicated by: VCL-1027 External SSH service under systemd fails to restart if several restarts are rapidly attempted