[one-users] Reference CONTEXT variables within CONTEXT

[Carlos Martín Sánchez]

Hi,

I'm glad you found a way to make it work.

If it is really needed, we could add support to reference other context
attributes. Please open a request If you still think it would be better.

Cheers,
Carlos

--
Join us at OpenNebulaConf2013 <http://opennebulaconf.com> in Berlin, 24-26
September, 2013
--
Carlos Martín, MSc
Project Engineer
OpenNebula - The Open-source Solution for Data Center Virtualization
www.OpenNebula.org | cmartin at opennebula.org |
@OpenNebula<http://twitter.com/opennebula><cmartin at opennebula.org>


On Thu, May 16, 2013 at 2:14 PM, Valentin Bud <valentin.bud at gmail.com>wrote:

> Hello Community,
>
> First of all, I apologise I forgot to say hi in my previous E-Mail :|.
>
> On Thu, May 16, 2013 at 10:28:14AM +0300, Valentin Bud wrote:
> > I am trying to reference the CONTEXT variables from within CONTEXT.
> >
> > For example, I define the DOMAIN="domain.tld" and the HOSTNAME="host".
> > I would like to have a variable FQDN="$HOST.$DOMAIN.".
> >
> > I have tried to achieve the above using the following in CONTEXT section
> > of the template.
> >
> > Case I
> > --
> >
> > $ onetemplate show vars
> >
> > TEMPLATE CONTENTS
> > CONTEXT=[
> >   DOMAIN="domain.tld",
> >   FQDN="$DOMAIN.$HOSTNAME.",
> >   HOSTNAME="host" ]
> >
> > [... output omitted for brevity ...]
> >
> > Instantiating the template results in the following variables added to
> > the VM.
> >
> > $ onevm show vars
> >
> > VIRTUAL MACHINE TEMPLATE
> > CONTEXT=[
> >   DISK_ID="1",
> >   DOMAIN="domain.tld",
> >   *FQDN="..",*
> >   HOSTNAME="host",
> >   TARGET="hda" ]
> >
> > Case II
> > --
> >
> > $ onetemplate show vars
> >
> > CONTEXT=[
> >   DOMAIN="domain.tld",
> >   FQDN="$CONTEXT[$DOMAIN].$CONTEXT[$HOSTNAME].",
> >   HOSTNAME="host" ]
> > [... output omitted for brevity ...]
> >
> > Same result in the VM.
> >
> > $ onevm show vars
> >
> > VIRTUAL MACHINE TEMPLATE
> > CONTEXT=[
> >   DISK_ID="1",
> >   DOMAIN="domain.tld",
> >   *FQDN=".."*,
> >   HOSTNAME="host",
> >   TARGET="hda" ]
> > [... output omitted for brevity ...]
> >
> > Is it possible to achieve what am I trying or should I search for a new
> > solution?
> >
> > I have a simple use case. I am generating, via a hook, the ssh keys for
> > the VM in question. At boot I copy the keys from /mnt to /etc/ssh via
> > a crafted one-context script. Awesome mechanism by the way :-).
> >
> > I am generating the keys in
> > CONTEXT_FILES_LOCATION=/var/lib/cloud/context/host.domain.tld.
> >
> > I would like to use the following in the CONTEXT section:
> >
> > CONTEXT=[
> > CONTEXT_FILES_LOCATION=/var/lib/cloud/context/host.domain.tld./,
> > DOMAIN="domain.tld",
> > FILES="$CONTEXT_FILES_LOCATION/$FQDN/ssh_host_rsa_key ...",
> > HOSTNAME="host",
> > FQDN="$HOSTNAME.$DOMAIN." ]
> >
> > This makes the template much more dynamic. I would just change the
> HOSTNAME
> > and the paths would get generated dynamically.
> >
>
> Writing the HOSTNAME, DOMAIN, CONTEXT_FILES_LOCATION outside the CONTEXT
> section and referencing them from within CONTEXT works :-).
>
> Example
> --
>
> $ onetemplate show vars
>
> TEMPLATE CONTENTS
> CONTEXT=[
>   CONTEXT_FILES_LOCATION="$CONTEXT_FILES_LOCATION",
>   DOMAIN="$DOMAIN",
>   FILES="$CONTEXT_FILES_LOCATION/$FQDN/ssh_host_rsa_key
>   $CONTEXT_FILES_LOCATION/$FQDN/ssh_host_rsa_key.pub",
>   FQDN="$HOSTNAME.$DOMAIN.",
>   HOSTNAME="$HOSTNAME" ]
> CONTEXT_FILES_LOCATION="/var/lib/cloud/context"
> CPU="1"
> DISK=[
>   IMAGE="vars" ]
> DOMAIN="domain.tld"
> GRAPHICS=[
>   LISTEN="0.0.0.0",
>   TYPE="vnc" ]
> HOSTNAME="host"
> MEMORY="2048"
> NIC=[
>   NETWORK="host.domain.tld" ]
> OS=[
>   ARCH="x86_64" ]
> VCPU="4"
>
> After instantiating the machine I have the desired results.
>
> $ onevm show vars
>
> VIRTUAL MACHINE TEMPLATE
> CONTEXT=[
>   CONTEXT_FILES_LOCATION="/var/lib/cloud/context",
>   DISK_ID="1",
>   DOMAIN="dev.corview.de",
>   FILES="/var/lib/cloud/context//ssh_host_rsa_key
>   /var/lib/cloud/context//ssh_host_rsa_key.pub",
>   FQDN="vars.domain.tld.",
>   HOSTNAME="vars",
>   TARGET="hda" ]
>
> Now I can easily generate SSH host keys for each machine if this wasn't
> done already in a previous VM instantation.
>
> Thanks and sorry for the noise. If this is mentioned somewhere in the
> docs, my bad.
>
> Cheers and Goodwill,
>
> --
> Valentin Bud
> http://databus.pro/ | valentin at databus.pro
> _______________________________________________
> Users mailing list
> Users at lists.opennebula.org
> http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
>
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