Re: [RFC PATCH] bind: add support for read-only rootfs

[Mark Hatle <mark.hatle@windriver.com>]

On 11/21/13, 6:12 AM, Phil Blundell wrote:
> On Thu, 2013-11-21 at 00:59 -0600, Mark Hatle wrote:
>> +# When using a read-only rootfs additional setup may be required
>> +# uncomment the following line to make bind start in read-only rootfs
>> +#ALLOW_ROOTFS_READ_ONLY="yes"
>
> If the filesystem is read-only then it's going to be fairly difficult
> for the user to uncomment this line on the target.

A post image process script would be capable of un-commenting that line (or 
simply replacing the file with a specific image specific configuration.)

> Why would you ever want this variable to be set to anything other than
> "yes"?  If your filesystem is not in fact read-only then it isn't going
> to have any effect, and if your filesystem is read-only then bind won't
> work without it.
>
>> ++	[ `is_on_read_only_partition /etc/bind` = "yes" ] && bind_mount /var/volatile/bind/etc /etc/bind
>> ++	[ `is_on_read_only_partition /var/named` = "yes" ] && bind_mount /var/volatile/bind/named /var/named
>
> Is it really necessary to mount a tmpfs at /etc/bind?  Can't those files
> just be relocated somewhere else?

My understanding is both locations need to be RW for bind to work properly.  In 
a normal READONLY filesystem configuration, neither is RW by default.

--Mark

> p.
>
>