DHCP Host Name Option

[krzysztof-sprzaczkowski]

Hi,
Is it possible to enable on the Arista switch sending Host-Name option in DHCP? - thru CLI or SDK API
By default only Client-Identifier option is sent.

Regards,
Krzysztof

[krzysztof-sprzaczkowski]

I will add that I need to send DHCP host-name option on Management interface only.

In the first step I modified /etc/dhcp/dhclient-default.conf manually adding "send host-name = gethostname();" to verify that new option will be sent

interface "ma1" {
send dhcp-client-identifier "Arista-2899.3a43.71dc-Ma1";
send host-name = gethostname();
}

It works but obviously it is not right way - it was a simple verification only.

In the next step I tried to use Event-Handler mechanism described https://eos.arista.com/adding-interface-dhcp-support-with-an-event-handler/ but unfortunately it doesn't work for me.

I have prepare my own /mnt/flash/dhclient.conf file (with an additional line "send host-name = gethostname();" to force sending host-name) and added thsi file as a parameter to dhclient ( dhclient -pf $PIDFILE -lf $LEASEFILE -sf $DHCLIENTSCRIPT -cf $DHCLIENTCONF $KERNELINTF)

Next I tested the following scenarios:

1. When I implement everything exactly according to the recipe I can see that IP address/mask on Management (ma1) interface is set as static (because of ip address $new_ip_address $new_subnet_mask" is in the eosdhclientscript script). In such case 'option host-name' is not sent.

2. When I change one line in the eosdhclientscript script to "ip address dhcp" then the option is sent but DHCP server assigns a new IP address every few second but I can not see any IP address on Ma1 interface

3. When I set additionally "ip address dhcp" on CLI for Ma1 interface I can see 2- dhclient processes on Linux CLI
   bash-4.3# ps -ef | grep dhclient
   root 8052 8042 0 17:18 ? 00:00:00 dhclient -pf /var/run/dhclient.Management1.pid -lf /var/lib/dhclient/dhclient.Management1.leases -sf /mnt/flash/eosdhclientscript -cf /mnt/flash/dhclient-psme.conf ma1
   root 8299 1 0 17:20 ? 00:00:00 dhclient -e SYSNAME=ar -e SYSDBSOCKNAME=sysdb -sf /etc/dhcp/dhclient-script.py -pf /var/run/dhclient-default.pid -cf /etc/dhcp/dhclient-default.conf -lf /var/lib/dhclient/dhclient-default.leases -e ma1=Management1

Do you have any idea how to configure DHCP properly to send host-name option on Ma1 interface?

Regards,
Krzysztof

[tsuna]

Not sure if this is the best place where to ask for this kinda non-EosSdk related thing, I'd recommend reaching out to support@arista.com, they can either tell you what to do or find someone that knows.