Re: [Xen-users] how to start VMs in a particular order

["squidmobile@xxxxxxxxxxx" <squidmobile@xxxxxxxxxxx>]

28 jun 2014

greetings,

> Is this a feature, or did you happen to create the links in the desired
> order?  I see both possibilities, i. e. sorting the directory entries as
> a feature, or start the VMs in the order the files/links have been
> created/are found as directory entries.

i use jfs, which happens to have (what i think is) the beautiful
characteristic of always listing files in alphabetic sequence.  no
piping through sort or anything else.

i ran this command:
  ln -s /source/dir/vm-names*.cfg .
  mv vm-name 01.vm-name.cfg
  mv vm-name 02.vm-name.cfg
  ...
  plus, delete the unwanted symbolic links.
or you can ln -s file by file.  whatever works for you.

when i reboot my system, the combination of jfs and numeric
symbolic link name puts them in the correct sequence, as listed by
xl list.

> In this case, the VM with the name server
> needs to be up first, then the VM with the firewall, then the VM with
> the NFS server and finally the rest of them in no particular order.

hmmm.  can some of these come up in parallel?  does the firewall
use ip addresses from the dns server, or does it hard code them?
does the firewall separate the nfs server from the dns server?

granted, the lack of dns affects the nfs clients, but wouldn't the
nfs server (mostly) ignore dns until it finished booting and began
nfs operations?

> How do you find out whether a VM is fully up or not even within the very
> same VM?

well, dom0 can maintain a log of vm console output (i forget
exactly where, but i think somewhere under /var/log/xen/console).
tweak your vm startup scripts to echo something like "start the
next vm" and let the dom0 auto script wait for the signal before xl
create the next vm.  put a sleep 5 in the auto script to keep it
from thrashing.  would some variant of this work for you?

i hope this helps.
frank smith

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