rageek

A place for Unix Thoughts and Ideas

Monthly Archives: August 2012

Determining global zone name from inside a solaris 11 zone

The default security of Solaris zones masks the name of the host’s global zone.

In my environment we don’t have the requirement to mask the global zone name and it is very useful for our internal customers as wells as our engineering staff to have this info easily available.

There are a couple ways to go about this. I had 2 primary requirements for my solution. The information provided to the zone needed to be consistently accurate and up to date in the case that I migrate a zone to another hosts and I also do not want it to be obvious that this information is being provided to the zone.

One easy solution is to create a file on the global zone and loopback mount it into the zone.
A Very simple solution, but LOFS mounts appear in the zone’s df output and I think that is being a little too obvious.

Previously, I used a trick with the arp cache and probe-based IPMP to figure out the global zone.
But in Solaris 11, transitive probing and virtual nics have put an end to that.

My solution for the problem uses lofi and device mapping to make the information available to the zone.

Lofiadm is great tool which allows you to map files to devices, this is very handy for mounting iso’s or updating boot miniroots. The file can be arbitrary, but must be a multiple of 512bytes. This can be accomplished using the mkfile command and cat.

The first thing I do is generate the file in the global zone. I do by using the hostname command, and then creating another file to pad the original file to 512bytes.  Read more of this post

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