Problem: NFS server does not start after upgrade to UCS 4.3
After upgrade your NFS server does not start and shows the following output:
root@master:~# service nfs-kernel-server status
● nfs-server.service - NFS server and services
Loaded: loaded (/lib/systemd/system/nfs-server.service; enabled; vendor preset: enabled)
Drop-In: /lib/systemd/system/nfs-kernel-server.service.d
└─univention-nfs.conf
Active: inactive (dead) since Mon 2019-02-11 22:06:43 CET; 1min 6s ago
Process: 769 ExecStopPost=/usr/sbin/exportfs -f (code=exited, status=0/SUCCESS)
Process: 766 ExecStopPost=/usr/sbin/exportfs -au (code=exited, status=0/SUCCESS)
Process: 764 ExecStop=/usr/sbin/rpc.nfsd 0 (code=exited, status=0/SUCCESS)
Process: 743 ExecStart=/usr/sbin/rpc.nfsd $RPCNFSDARGS (code=exited, status=0/SUCCESS)
Process: 738 ExecStartPre=/usr/sbin/exportfs -r (code=exited, status=0/SUCCESS)
CPU: 6ms
Feb 11 22:06:43 master systemd[1]: Starting NFS server and services...
Feb 11 22:06:43 master systemd[1]: Stopped NFS server and services.
Furthermore you might see entries in /var/log/syslog:
Feb 11 13:29:42 master nfsdcltrack[27242]: Failed to init database: -13
Feb 11 13:29:42 master kernel: [258455.107012] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
Feb 11 13:29:42 master kernel: [258455.163198] nfsd: last server has exited, flushing export cache
Solution
During the upgrade a symbolic link has not been properly removed and thus confuses systemd.
To solve do:
cd /etc/systemd/system/multi-user.target.wants
rm -f nfs-kernel-server.service
systemctl daemon-reload
systemctl start nfs-server