Re: [vserver] Problem with bind mount

From: Erdem Bayer <ebayer_at_bayer.gen.tr>
Date: Wed 19 Aug 2009 - 12:00:44 BST
Message-ID: <20090819140044.6c5fb47b@ag6b-neptune-03>

Hi

Is it safe to do the bind mounts from the host? What are the pros and cons?

Kind Regards
Erdem Bayer

On Wed, 19 Aug 2009 06:51:24 -0400
"John A. Sullivan III" <jsullivan@opensourcedevel.com> wrote:

> On Wed, 2009-08-19 at 13:23 +0300, Erdem Bayer wrote:
> > Hi
> >
> > I have a debian lenny i386 vserver running on lenny amd64 host with the following fstab entry:
> >
> > none /proc proc defaults 0 0
> > none /tmp tmpfs size=256m,mode=1777 0 0
> > none /dev/pts devpts gid=5,mode=620 0 0
> > /home /home bind bind 0 0
> > /iscsi/www /var/www bind bind 0 0
> > /iscsi/log/concero /var/log bind bind 0 0
> >
> > When I start a vserver, I see these errors in the output:
> >
> > secure-mount: mount(): Invalid argument
> > /etc/vservers/concero/fstab:5:1: failed to mount fstab-entry
> > secure-mount: mount(): Invalid argument
> > /etc/vservers/concero/fstab:6:1: failed to mount fstab-entry
> >
> > But the vserver starts and the directories in fstab file are mounted anyway.
> >
> > I don't know if it makes a difference but /home fs is ext3, /iscsi is formatted with ocfs2 and mounted with iscsi. I can mount them manually with the following command:
> >
> > sudo mount --bind /iscsi/log/concero /etc/vservers/concero/vdir/var/log
> >
> > When I dig deeper I found that secure-mount is called with the following parameters:
> >
> > ++ pushd /etc/vservers/concero/vdir
> > ++ test -w etc -o -w etc/mtab
> > ++ /usr/lib/util-vserver/secure-mount -a --chroot --fstab /etc/vservers/concero/fstab --rootfs no
> >
> > Here are the strace of the manual running of secure-mount (if it helps):
> >
> >
> > chroot(".") = 0
> > chdir("/") = 0
> > fchdir(3) = 0
> > chroot(".") = 0
> > chdir("/var/www") = 0
> > open(".", O_RDONLY|O_DIRECTORY) = 6
> > fchdir(4) = 0
> > chroot(".") = 0
> > fchdir(6) = 0
> > close(6) = 0
> > mount("/iscsi/www", ".", 0x7fffdf03e67f, MS_NODEV|MS_BIND, 0x7f9ad703f070) = 0
> > fchdir(3) = 0
> > chroot(".") = 0
> > chdir("/var/www") = 0
> > open(".", O_RDONLY|O_DIRECTORY) = 6
> > fchdir(4) = 0
> > chroot(".") = 0
> > fchdir(6) = 0
> > close(6) = 0
> > mount("/iscsi/www", ".", 0x7fffdf03e67f, MS_NODEV|MS_REMOUNT, NULL) = -1 EINVAL (Invalid argument)
> > write(2, "secure-mount: mount()"..., 21secure-mount: mount()) = 21
> > write(2, ": "..., 2: ) = 2
> > write(2, "Invalid argument"..., 16Invalid argument) = 16
> > write(2, "\n"..., 1
> > ) = 1
> > write(2, "/etc/vservers/concero/fstab"..., 27/etc/vservers/concero/fstab) = 27
> > write(2, ":5:1"..., 4:5:1) = 4
> > write(2, ": failed to mount fstab-entry\n"..., 30: failed to mount fstab-entry
> > ) = 30
> > chdir("/") = 0
> > fchdir(3) = 0
> >
> >
> > chroot(".") = 0
> > chdir("/var/log") = 0
> > open(".", O_RDONLY|O_DIRECTORY) = 6
> > fchdir(4) = 0
> > chroot(".") = 0
> > fchdir(6) = 0
> > close(6) = 0
> > mount("/iscsi/log/concero", ".", 0x7fffdf03e6a9, MS_NODEV|MS_BIND, 0x7f9ad703f090) = 0
> > fchdir(3) = 0
> > chroot(".") = 0
> > chdir("/var/log") = 0
> > open(".", O_RDONLY|O_DIRECTORY) = 6
> > fchdir(4) = 0
> > chroot(".") = 0
> > fchdir(6) = 0
> > close(6) = 0
> > mount("/iscsi/log/concero", ".", 0x7fffdf03e6a9, MS_NODEV|MS_REMOUNT, NULL) = -1 EINVAL (Invalid argument)
> > write(2, "secure-mount: mount()"..., 21secure-mount: mount()) = 21
> > write(2, ": "..., 2: ) = 2
> > write(2, "Invalid argument"..., 16Invalid argument) = 16
> > write(2, "\n"..., 1
> > ) = 1
> > write(2, "/etc/vservers/concero/fstab"..., 27/etc/vservers/concero/fstab) = 27
> > write(2, ":6:1"..., 4:6:1) = 4
> > write(2, ": failed to mount fstab-entry\n"..., 30: failed to mount fstab-entry
> > ) = 30
> > close(5) = 0
> > _exit(0) = ?
> >
> > Kind Regards
> > Erdem Bayer
> Might it be faster and easier to do the bind mounts from the host,
> e.g.,
> /somesource/iscsi/log/concero /vservers/vserver1/var/log bind bind 0 0
>
> --
> John A. Sullivan III
> Open Source Development Corporation
> +1 207-985-7880
> jsullivan@opensourcedevel.com
>
> http://www.spiritualoutreach.com
> Making Christianity intelligible to secular society
>
Received on Wed Aug 19 12:00:32 2009

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