- RHEL 7.2 up to day as for October 2016
- Physical system
- NetworkManager disabled
- Network configured through the teaming of 2x10G NICs (eth0 & eth1) as lacp0
- (irrelevant) IP addresses are configured on VLAN subinterfaces lacp0.XXX and lacp0.YYY
- (also irrelevant) These systems are destined to be Oracle 12c nodes
The network connectivity is 100% OK, benchmarks confirms the LACP is fully functionnal and approaches the 20 GBps theoretical maximum.
systemd doesn't detect that the network stack is stopped during shutdown and waits until too late to unmount NFS shares and thus fails to unmount them which leads to it hanging indefinitly for the NFS server to respond.
After running "systemctl stop network.service", both network.target and network-online.target are still considered as active.
What I've come to so far :
NFS mounts added via the
/etc/fstab file are translated into
*.mount systemd units. Those units automatically depends on
remote-fs.target which depends on `network-online.target.
From the documentation, it seems network*.target depends on a network management tool to detect whether the network is up and such. This can be
systemd-nerworkd, or anything else (but what ?). I think my problem may be here as it seems our jumpstart template relies on the old init scripts for managing the interfaces. And I doubt systemd can interact with it to be informed of the network being up or down (despite being used to stop the network stack with
systemctl stop network)
My second hypothesis is that network teaming using libteam/teamd even through ifcfg-* files are out of the systemd network.target scope. There seem to be no dependency between the teamd systemd units (including email@example.com) and the network units. That would explain why the only systems displaying this issue are those LACP-enabled systems, and we had not the problem before when using typical bonding.
So my question : What solution do I have to make sure my NFS shares are unmounted before my network stack is brought down, typically when rebooting the system ?
PS: would be better if the said solution didn't come from the way to create NFS mounts, so that someone who has to add a share to this server doesn't have to be informed of the special steps to take. This seems nearly impossible considering our production process.