Just before this weekend we had some issues with an old server which
had lost one of the disks in it’s mirror and the second was starting
to fail. This is a server we plan to decommission, but unfortunately
we can’t do this yet as it still has a lot of important services
running. This server was running an FreeBSD 7.2 and thankfully all
services we care about was running in a jail. So it was decided, to
get a temporary solution to this, we would create a new FreeBSD 8.4
virtual machine and move the jail as is to the new machine.
From my earlier experience with running 9.x on 10 I expected this to
go like a charm, but unfortunately this was not the case. After
several ours of transfering the jail to the new host, the time had
finally come to start it. It started just as expected, but some of the
services did not come up. More specifically stunnel and mysql. After
some debugging it turned out they both failed on the function
‘kse_create’. This function is a part of the kernel supported user
threads
(kse(2)).
Support for these was removed with FreeBSD 8, and since I was staying
with the 7.2 userland in the jail it was not just to recompile the
affected programs in the jail.
To solve this I recompiled the affected programs for 8.4, before I
installed them to the 7.2 jail. This did have one problem though, the
binary was linked against libraries which wasn’t available in FreeBSD
7.2. The natural solution for this would be the compat8x port, but it
contained a lot of libraries which wasn’t necessary and was lacking a
few which was needed. So instead of using compat8x, I chose to
manually copy the missing libraries from the 8.4 machine and install
them to the 7.2 jail. Then after some compiling the services which
originally used kse was back up again without it.
Currently I’m trying to automatically installing FreeBSD on zfs by
netbooting a comuter. As a part of this I have to pxeboot a mfsbsd
image which actually does the install. So far this is how I got mfsbsd
to netboot of a FreeBSD host.
First of all we need to grab an mfsbsd image and setup the root for
tftp. The tftp root folder is commonly placed at /tftpboot.
# fetch http://mfsbsd.vx.sk/files/iso/10/amd64/mfsbsd-10.0-RELEASE-amd64.iso
# mkdir -p /tftpboot/mfsroot
# tar -xf mfsbsd-10.0-RELEASE-amd64.iso -C /tftpboot/mfsroot
# cp /boot/pxeboot /tftpboot
After this is done we will need an tftp server. FreeBSD comes with one
in the base system so we will only have to activate this in
/etc/inetd.conf. This is done by uncommenting the following lines in
/etc/inetd.conf, the second line is only necessary if you want to use ipv6.
tftp dgram udp wait root /usr/libexec/tftpd tftpd -l -s /tftpboot
tftp dgram udp6 wait root /usr/libexec/tftpd tftpd -l -s /tftpboot
Unfortunately the freebsd pxe loader only supports nfs without
recompiling it. This isn’t a big issue though as FreeBSD as an nfs
server in the base system. To tell nfsd to share the location where we
placed the mfsbsd image, add the following to /etc/exports
/tftpboot/mfsroot -ro -maproot=root -network=192.168.1.0 -mask=255.255.255.0
Before we are done we will need an dhcp server, if you don’t have one
allready you can get one from port by using the following command.
# pkg install isc-dhcp42-server
Following is an example of dhcpd.conf, you will probably have to
modify it for your needs.
subnet 192.168.1.1 netmask 255.255.255.0 {
range 192.168.1.50 192.168.1.100;
option routers 192.168.1.1;
option domain-name-servers 192.168.1.1;
option domain-name "domain.tld";
default-lease-time 3600;
max-lease-time 3600;
next-server 192.168.1.2;
option root-path "/tftpboot/mfsroot";
filename "pxeboot";
}
host host.domain.tld {
ethernet AA:BB:CC:DD:EE:FF;
option host-name "host";
}
At last before we can netboot mfsbsd we will have to activate and
start all the services we just configured. This can be done with the
following commands.
# sysrc dhcpd_enable=YES
# sysrc nfsd_enable=YES
# sysrc mountd_enable=YES
# sysrc inetd_enable=YES
# service nfsd start
# service isc-dhcpd start
# service inetd start
Finally we should be able to boot netboot mfsbsd. Going forward I’m
looking into modifying the mfsbsd image to include either an installer
or some bootstraping to download and execute an installer. The goal is
to install FreeBSD without human intervention, only by pxe booting a
host in the correct subnet.
While building a custom mfsbsd image I had to fetch the distfiles and
verify their hash, to do this simpler and faster I threw together this
shellscript, which I’m going leave here for later. The script will
automatically download a manifest via http or ftp, then it will
continue by downloading all files defined in the manifest check their checksum.
#!/bin/sh
set -e
url=${1:-"http://ftp.uninett.no/FreeBSD/releases/amd64/amd64/10.1-RC1/"}
fetch ${url}/MANIFEST
cat MANIFEST | while read file x; do
fetch ${url}/${file}
done
cat MANIFEST | while read file sum x; do
echo -n "${file}: "
if [ "$(sha256 -q ${file})" = "${sum}" ]; then
echo "OK"
else
echo "FAIL"
fi
done