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How do I find the DHCP lease time when I am using systemd-networkd?
My network is defined in /etc/systemd/network/eth0.network:
[Match]
Name=eth0
[Network]
DHCP=yes
There are other question on this site asking for the same information but they weren't using systemd-networkd but dhclient or some other method.
I've tried looking in journalctl to no avail. I’m using ArchLinux.
Depending on the OS; Enabling debug isn't always necessary.
systemd-networkd should store the lease info under /run/systemd/netif/leases/
i.e.
cat /run/systemd/netif/leases/2
Per Lennart's post here, you have to change systemd-networkd log level to debug.
If you wanted to have it on all the time you could use a drop-in unit:
mkdir -p /etc/systemd/system/systemd-networkd.service.d
cat << IN > /etc/systemd/system/systemd-networkd.service.d/10-debug.conf
[Service]
Environment=SYSTEMD_LOG_LEVEL=debug
IN
systemctl daemon-reload
systemctl restart systemd-networkd
I can't find authoritative documentation for this, but I think networkd's DHCP client uses the received DHCP lease duration to set valid_lft and preferred_lft on the address in kernel, and thus the remaining lease duration is simply shown with ip address show:
$ ip -4 a s eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
inet 192.168.2.7/24 brd 192.168.2.255 scope global dynamic eth0
valid_lft 59397sec preferred_lft 59397sec
grep lease /var/log/syslog.