Diskless node. Unable to mount root fs via NFS

Question

Server: CentOS 7
NFS root filesystem for client and Kernel: Slackware 14.1

I enabled "Root file system on NFS" and "IP: kernel level autoconfiguration" with "DHCP,BOOTP,RARP" support, recompiled the Kernel(3.10.17).

TFTP,NFS,DHCP all ready.
I ensure that NFS can be mounted by a linux client.(mount -t nfs ... )
DHCP and TFTP worked properly, and I can boot from an isolinux kernel use ram root filesystem.

Now, I need a diskless node so I need the kernel to mount a root filesystem via NFS.

kernel kernels/vmlinuz append ip=dhcp root=/dev/nfs nfsroot=192.168.1.4:/srv/diskless/slackware-14.1,nfsvers=3 raid=noautodetect 

I get the error when boot

VFS: Unable to mount root fs via NFS, trying floppy. 

Also, it seems the kernel didn't get an ipaddress by DHCP when boot.
(No information about displayed, ether I use "ip=192.168.1.7: ... :eth0" manually)

As the Slackware use huge-kernel, so I don't have an initrd image.(Problem may be here?)(My Computer's Linux didn't have ether, and works properly :) )

Or may be some option in kernel menuconfig I didn't select :( .(and I really need to know it)

Answer 1

I was having the same problem as you and I was able to find a solution. I'm also using Slackware 14.1 and the huge kernel.

My problem was that the huge kernel doesn't include the Ethernet driver, in my case, the e1000 driver was compiled as a module in the huge.s kernel, I thought that all drivers were included with this kernel, my assumption was wrong. Once I added the e1000 driver into the kernel (not as a module) everything started to work, and I was able to mount the root with NFS.

You should see something like this before the VFS mount message:

[ 3.325468] e1000: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX [ 3.337383] Sending DHCP requests ., OK [ 3.340259] IP-Config: Got DHCP answer from 192.168.10.5, my address is 192.168.10.6 [ 3.340870] IP-Config: Complete: [ 3.341128] device=eth0, hwaddr=08:00:27:c0:3e:a7, ipaddr=192.168.10.6, mask=255.255.255.0, gw=255.255.255.255 [ 3.341682] host=test, domain=, nis-domain=(none) [ 3.341989] bootserver=192.168.10.5, rootserver=192.168.10.5, rootpath= [ 3.342198] nameserver0=192.168.10.5 [ 3.342816] md: Skipping autodetection of RAID arrays. (raid=autodetect will force) [ 3.382613] VFS: Mounted root (nfs filesystem) readonly on device 0:13.