Jail starts but doesn't start

Thu May 12 18:16:31 UTC 2011

> -----Original Message-----
> From: owner-freebsd-jail at freebsd.org [mailto:owner-freebsd-jail at freebsd.org]
> On Behalf Of Paul Schenkeveld
> Sent: Thursday, May 05, 2011 3:41 AM
> To: freebsd-jail at freebsd.org
> Subject: Re: Jail starts but doesn't start
>
> On Wed, May 04, 2011 at 04:24:11PM -0700, Mickey Harvey wrote:
> > Hosts /etc/rc.conf
> >
> >    1. ifconfig_bge0="inet 192.168.224.11 netmask 255.255.255.0"
> >    2. defaultrouter="192.168.224.1"
> >    3. sshd_enable="YES"
> >    4.
> >    5. linux_enable="YES"
> >    6. zfs_enable="YES"
> >    7. jail_enable="YES"
> >    8. jail_list="www0 dns0 smarty0 centos"
> >    9.
> >    10. ifconfig_bge0_alias0="inet 192.168.224.12 netmask 255.255.255.255"
> >    11. jail_www0_rootdir="/tank/jails/www0"
> >    12. jail_www0_hostname="www0"
> >    13. jail_www0_ip="192.168.224.12"
> >    14. jail_www0_devfs_enable="YES"
> >    15. jail_www0_exec_stop="/etc/rc.shutdown"
> >    16.
> >    17. #JAIL READY TO USE, JUST NEEDS APPROPRIATE FSTAB ENTRIES
> >    18. #ENTRIES ARE IN LOADER.CONF
> >    19. #TRIED TO BOOT WITH REQUIRED FSTAB BUT IT BROKE SO I REVERTED
> >    20. #5/3/11 MH
> >    21. #ifconfig_bge0_alias1="inet 192.168.224.13 netmask 255.255.255.255"
> >    22. #jail_deb0_rootdir="/tank/jails/deb0"
> >    23. #jail_deb0_hostname="deb0"
> >    24. #jail_deb0_ip="192.168.224.13"
> >    25. #jail_deb0_devfs_enable="YES"
> >    26. #jail_deb0_exec_start="/etc/init.d/rc 3"
> >    27. #jail_deb0_exec_stop="/etc/init.d/rc 0"
> >    28. #jail_deb0_flags="-l -u root"
> >    29.
> >    30. ifconfig_bge0_alias1="inet 192.168.224.14 netmask 255.255.255.255"
> >    31. jail_dns0_rootdir="/tank/jails/dns0"
> >    32. jail_dns0_hostname="dns0"
> >    33. jail_dns0_ip="192.168.224.14"
> >    34. jail_dns0_devfs_enable="YES"
> >    35. jail_dns0_exec_stop="/etc/rc.shutdown"
> >    36.
> >    37. ifconfig_bge0_alias2="inet 192.168.224.15 netmask 255.255.255.255"
> >    38. jail_smarty0_rootdir="/tank/jails/smarty0"
> >    39. jail_smarty0_hostname="smarty0"
> >    40. jail_smarty0_ip="192.168.224.15"
> >    41. jail_smarty0_devfs_enable="YES"
> >    42. jail_smarty0_exec_stop="/etc/rc.shutdown"
> >    43.
> >    44. ifconfig_bge0_alias3="inet 192.168.224.16 netmask 255.255.255.255"
> >    45. jail_centos_rootdir="/tank/jails/centos"
> >    46. jail_centos_hostname="centos"
> >    47. jail_centos_ip="192.168.224.16"
> >    48. jail_centos_devfs_enable="YES"
> >
> >
> > Result of jls after /etc/rc.d/jail start centos (notice there's no
> > entry for
> > centos)
> >
> >    JID  IP Address      Hostname                      Path
> >      1  192.168.224.12  www0                          /tank/jails/www0
> >      2  192.168.224.14  dns0                          /tank/jails/dns0
> >      3  192.168.224.15  smarty0                       /tank/jails/smarty0
> >
> >
> > No error messages when starting or stopping centos jail.
> > /var/run contains jail_centos.id
> > Alias exists on bge0.
> >
> > So I tried "jexec 4 /bin/bash" figuring jls just isn't showing the
> > centos jail for some reason but:
> > jexec: jail_attach(4): Invalid argument
> >
> > Anybody have any idea about what might be happening here?
>
> This usually happens when there are no processes running in the jail to keep
it
> up.  By default, jails started thru rc.d/jail are not persistent.
> Try adding something like cron_enable="YES" to rc.conf inside the jail.

The /etc/rc.d/jail script will (by default) run "/bin/sh /etc/rc" as the jailed
process. On FreeBSD, /etc/rc is responsible for booting the system. By default,
a vanilla FreeBSD jail will run syslogd, sendmail, and cron, all of which fork
and daemonize, triply allowing the jail to persist.

CentOS -- which also has /etc/rc (as a symbolic link to /etc/rc.d/rc) --
meanwhile may not have any services that are enabled by default. I would either

a. chroot(8) into the jail and use chkconfig(8) to enable something like cron in
runlevel 5 (e.g. chkconfig --level 5 crond on)
or simply...
b. ln -sf ../init.d/crond /tank/jails/centos/etc/rc5.d/S90crond

On a side note: this is the first that I've ever heard that you could run CentOS
Linux in a FreeBSD jail. It should work -- afterall, my CentOS 4.7 box appears
to have /etc/rc as a symlink to /etc/rc.d/rc, so in-theory there should be no
problems with the /etc/rc.d/jail FreeBSD script from firing up a CentOS jail
(*cough* in-theory *cough*).

Do let me know how you fair.
--
Devin

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