Building NanoBSD inside a jail
- by ptomli
I'm trying to setup a jail to enable building a NanoBSD image. It's actually a jail on top of a NanoBSD install.
The problem I have is that I'm unable to mount the md device in order to do the 'build image' part. Is it simply not possible to mount an md device inside a jail, or is there some other knob I need to twiddle?
On the host
/etc/rc.conf.local
jail_enable="YES"
jail_mount_enable="YES"
jail_list="build"
jail_set_hostname_allow="NO"
jail_build_hostname="build.vm"
jail_build_ip="192.168.0.100"
jail_build_rootdir="/mnt/zpool0/jails/build/home"
jail_build_devfs_enable="YES"
jail_build_devfs_ruleset="devfsrules_jail_build"
/etc/devfs.rules
[devfsrules_jail_build=5]
# nothing
Inside the jail
[root@build /usr/obj/nanobsd.PROLIANT_MICROSERVER]# sysctl security.jail
security.jail.param.cpuset.id: 0
security.jail.param.host.hostid: 0
security.jail.param.host.hostuuid: 64
security.jail.param.host.domainname: 256
security.jail.param.host.hostname: 256
security.jail.param.children.max: 0
security.jail.param.children.cur: 0
security.jail.param.enforce_statfs: 0
security.jail.param.securelevel: 0
security.jail.param.path: 1024
security.jail.param.name: 256
security.jail.param.parent: 0
security.jail.param.jid: 0
security.jail.enforce_statfs: 1
security.jail.mount_allowed: 1
security.jail.chflags_allowed: 1
security.jail.allow_raw_sockets: 0
security.jail.sysvipc_allowed: 0
security.jail.socket_unixiproute_only: 1
security.jail.set_hostname_allowed: 0
security.jail.jail_max_af_ips: 255
security.jail.jailed: 1
[root@build /usr/obj/nanobsd.PROLIANT_MICROSERVER]# mdconfig -l
md2 md0 md1
md0 and md1 are the ramdisks of the host.
bsdlabel looks sensible
[root@build /usr/obj/nanobsd.PROLIANT_MICROSERVER]# bsdlabel /dev/md2s1
# /dev/md2s1:
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
a: 1012016 16 4.2BSD 0 0 0
c: 1012032 0 unused 0 0 # "raw" part, don't edit
newfs runs ok
[root@build /usr/obj/nanobsd.PROLIANT_MICROSERVER]# newfs -U /dev/md2s1a
/dev/md2s1a: 494.1MB (1012016 sectors) block size 16384, fragment size 2048
using 4 cylinder groups of 123.55MB, 7907 blks, 15872 inodes.
with soft updates
super-block backups (for fsck -b #) at:
160, 253184, 506208, 759232
mount fails
[root@build /usr/obj/nanobsd.PROLIANT_MICROSERVER]# mount /dev/md2s1a _.mnt/
mount: /dev/md2s1a : Operation not permitted
UPDATE:
One of my colleagues pointed out
There are some file systems types that can't be securely mounted within
a jail no matter what, like UFS, MSDOFS, EXTFS, XFS, REISERFS, NTFS,
etc. because the user mounting it has access to raw storage and can
corrupt it in a way that it will panic entire system.
From http://www.mail-archive.com/[email protected]/msg160389.html
So it seems that the standard nanobsd.sh won't run inside a jail while it uses the md device to build the image. One potential solution I'll try is to chroot from the host into the build jail, rather than jexec a shell.
