Changes between Version 32 and Version 33 of UsersGuide

Timestamp:

Nov 11, 2013 10:17:43 AM (10 years ago)

Author:

Ted Faber

Comment:

--

UsersGuide

@@ -265 +265 @@
 
 {{{
-users:~$ /share/containers/containerize.py  DeterTest example4 ~/example4.tcl Containerized experiment DeterTest/example4 successfully created!
+users:~$ /share/containers/containerize.py  DeterTest example4 ~/example4.tcl
+Containerized experiment DeterTest/example4 successfully created!
 Access it via http://www.isi.deterlab.net//showexp.php3?pid=DeterTest&eid=example4
 }}}
@@ -355 +356 @@
 
 If you are using a qemu image that is not booting into containers, make sure [ReferenceGuide#BootableQemuImages grub is properly configured]
+
+Qemu images also mount users home directories as DETER physical nodes do.  In order to do this scalably the Qemu VMs mount the users' directories from the physical node.  The DETER infrastrcuture cannot support exporting users' directories to thousands of containers.
+
+However, a Qemu VM can only mount a few tens of user directories this way.  The limit is 23 user directories (24 in experiments that are not instantiated in a group).  Many projects have more than 23 users, but in practice only a few experimenters need access to the containers.
+
+To tell the container systems which user to mount, use the {{{--prefer-qemu-users}}} option to {{{containerize.py}}}.  That option takes a comma-separated list of usernames (no spaces).  When the Qemu nodes will always mount those users' home directories.  Others will be mounted if there is room.
+
+For example:
+
+{{{
+users:~$ /share/containers/containerize.py  --prefer-qemu-users=faber,jjh DeterTest example4 ~/example4.tcl
+}}}
+
+Will make sure that users {{{faber}} and {{{jjh}}} have their home directories mounted in any Qemu containers.
 
 === Changing The Packing Factor ===