[one-users] ONE context package

[Javier Fontan]

On Thu, Feb 27, 2014 at 2:13 PM, ML mail <mlnospam at yahoo.com> wrote:

> You are right I had to define the HOSTNAME variable in the template context
> and not as a tag in the already running VM. This means that I can't share
> templates among VMs, which is a bit stupid of course. With this solution you
> need one template per VM.

Not exactly. The value of custom variables can be a dynamic one [1] so
for example you can set the hostname to the name of the VM:

SET_HOSTNAME="$NAME"

or even a mix of static and dynamic data:

SET_HOSTNAME="$NIC[IP].domain.com"

[1] http://docs.opennebula.org/stable/user/virtual_machine_setup/cong.html#using-template-variables

> I see the issue with the HOSTNAME environment variable which is actually set
> at bootup of Linux so no problem with me for using a name such as
> SET_HOSTNAME like you suggest.

Good, I'll go with this.

> What do you think about having that same script also defining the hostname
> dynamically (if none was defined with the SET_HOSTNAME context variable)
> based on a DNS reverse lookup if the IP address of the VM has a PTR record?

I think it's a nice feature but it should only be set if the users
asks for it. For example, if some VM has a hardcoded hostname a user
does not expect it to be changed in case SET_HOSTNAME is not defined.
Another variable can be added like DNS_HOSTNAME=yes or even better,
specifying the IP where to get the name from:

DNS_HOSTNAME="$NIC[IP, NETWORK=\"Public\"]"

Any better idea?

I'm not sure which command to use to do the reverse lookup. One that
is in most of the distributions like host, nslookup or dig.

Cheers

>
>
>
> On Thursday, February 27, 2014 12:27 PM, Javier Fontan
> <jfontan at opennebula.org> wrote:
> Hi,
>
> ML, I think you should add it in the template context section, custom
> variables.
>
> I am adding scripts to configure the hostname in the context phase.
> These are simple scripts (one for rpm and other for deb based distros)
> that do just what you've commented, call hostname and modify the conf
> file. [1]
>
> I've just found a problem with it and it is calling the configuration
> variable "HOSTNAME". The shell automatically sets HOSTNAME and even if
> we don't specify it so it's a bit tricky to check wether the user
> intents to configure the hostname or leave it as it is.
>
> I am proposing to use the custom variable "SET_HOSTNAME" to configure
> the host name. What do you think?
>
> Concerning the addition of scripts in the context package, there is a
> guide in both the documentation [2] and the source code [3] on how to
> create custom packages. Having the required dependencies it's fairly
> easy to add or modify the configuration script you may need.
>
> Cheers
>
> [1] http://dev.opennebula.org/issues/2453
> [2]
> http://docs.opennebula.org/stable/user/virtual_machine_setup/cong.html#generating-custom-contextualization-packages
> [3]
> https://github.com/OpenNebula/one/tree/master/share/scripts/context-packages
>
> On Thu, Feb 27, 2014 at 8:02 AM, ML mail <mlnospam at yahoo.com> wrote:
>> Regarding the hostname script that's exactly what I did, I also tried to
>> redeploy this persistent image. Where exactly did you set the HOSTNAME
>> variable? I have setted it in the tags of that specific VM (where I would
>> also add the SSH_PUBLIC_KEY variable). But that might be wrong?
>>
>> Regards,
>> ML
>>
>>
>> On Thursday, February 27, 2014 2:47 AM, "Campbell, Bill"
>> <bcampbell at axcess-financial.com> wrote:
>> For item 1, no that should do it, just make sure it's executable and it
>> should run. (the vmcontext init.d script will run all scripts in the
>> /etc/one-context.d directory in order).  I set this up for Ubuntu, but I'm
>> pretty sure Debian is the same when it comes to setting the hostname.  You
>> mention you reboot the VM, you may have to redeploy (as the context script
>> is already generated from your previous deployment package).
>>
>> For item 2, you could include it in your base image, or in the example
>> provided, add it to the files repository along with that init.sh script,
>> and
>> then assign both files to the template.  This way the files will be
>> included
>> with the context information, will copy the ##-script over to the
>> instance,
>> and restart the vmcontext service.
>>
>> ________________________________
>> From: "ML mail" <mlnospam at yahoo.com>
>> To: "users" <users at lists.opennebula.org>
>> Sent: Wednesday, February 26, 2014 11:12:08 AM
>> Subject: Re: [one-users] ONE context package
>>
>> Hi Bill,
>>
>> Thanks for your answer and example scripts. I have a few more questions or
>> issues regarding your examples:
>>
>> - I tried out your small hostname script which I have copied on my Debian
>> 7
>> VM under /etc/one-context.d/98-hostname. I have then set in my VM a tag
>> called HOSTNAME with a value and rebooted the VM. Unfortunately the
>> hostname
>> did not get changed. Did I miss something here?
>>
>> - I suppose I would have to re-create the one-context package manually if
>> I
>> would like to include the aforementioned 98-hostname script in the
>> official
>> one-context package, correct? or I could manually copy it into my image
>> before deploying it?
>>
>> Regards,
>> ML
>>
>>
>>
>> On Wednesday, February 26, 2014 3:08 PM, "Campbell, Bill"
>> <bcampbell at axcess-financial.com> wrote:
>> We don't have the automatic lookup from DNS (that would rely on the DNS
>> record being created first prior to VM deployment), but we use a script
>> that
>> is placed in our base images /etc/one-context.d/ directory that does this
>> (which relies on option 2 as you mention below, a HOSTNAME context
>> variable):
>>
>> #!/bin/bash
>>
>> if [ -f /mnt/context.sh ]; then
>> . /mnt/context.sh
>> else
>> exit 0
>> fi
>> hostname $HOSTNAME
>> echo $HOSTNAME > /etc/hostname
>>
>> exit 0
>>
>> The above example is for our Ubuntu instances, so it may need to be
>> modified
>> for RHEL or SUSE based virtuals, if that's what you use.
>>
>> In addition, if using 4.4, use the files datastore and create an 'init.sh'
>> script that can then load up additional files that you assign to the
>> template (so you don't need to manually update each image).  We use an
>> init.sh script like this to inject new configuration/contextualization
>> options so we don't need to update our base image very often:
>>
>>
>> #!/bin/sh
>> #
>> # OpenNebula Init Script
>> #
>> # init.sh
>> #
>> # Copies additional context scripts to the appropriate directory
>> #
>> ## Set environment
>> SOURCE=/mnt
>> DEST=/etc/one-context.d
>>
>> if [ -f /etc/redhat-release ]; then
>> OSVERSION=RHEL
>> else
>> OSVERSION=UBUNTU
>> fi
>> if [ -f /usr/bin/rsync ]; then
>> echo "Applying additional contextualization scripts..."
>> else
>> if [ "$OSVERSION" != "UBUNTU" ]; then
>> yum -y install rsync
>> else
>> apt-get update && apt-get -y install rsync
>> fi
>> fi
>>
>> ## Copy Files. This will IGNORE any *.sh files in the source/destination
>> directories, as all context scripts
>> ## should NOT have the .sh extension.
>> for i in $(ls $SOURCE --ignore=*.sh)
>> do
>> if [ -f $DEST/$i ]; then
>> echo "$i exists in context directory. Skipping..."
>> else
>> rsync -au $SOURCE/$i /etc/one-context.d/
>> chown root.root /etc/one-context.d/*
>> chmod 700 /etc/one-context.d/*
>> service vmcontext restart
>> fi
>> done
>> exit 0
>>
>> This will check the OS Version and install the appropriate package.  It
>> will
>> NOT copy any file that has the .sh extension, but if you follow the
>> context
>> script standard of ##-<scriptname> then you can add additional context
>> upon
>> deployment.  Rudimentary, sure, but works well enough for us.
>>
>>
>> ________________________________
>> From: "ML mail" <mlnospam at yahoo.com>
>> To: users at lists.opennebula.org
>> Sent: Wednesday, February 26, 2014 5:39:46 AM
>> Subject: [one-users] ONE context package
>>
>> Hi,
>>
>> I am very happy with the ONE context package for automated
>> contextualization
>> on Debian and CentOS but I miss one feature: automatically and manually
>> setting the hostname of the VM.
>>
>> Basically it would be great to have the following two options:
>>
>> - automatically set the hostname of the VM based doing a reverse DNS
>> lookup
>> on the IP address, for example I have as reverse DNS entry
>> "one-vm-1-0-16-172.mydomain.com" then the hostname of my VM would be
>> automatically set to "one-vm-1-0-16-172".
>> - using a HOSTNAME tag in the VM to manually enter a hostname and
>> overriding
>> the automatic hostname attribution described above
>>
>> What do you think?
>>
>> Regards,
>> ML
>>
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>>
>>
>>
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>
>
> --
> Javier Fontán Muiños
> Developer
> OpenNebula - The Open Source Toolkit for Data Center Virtualization
> www.OpenNebula.org | @OpenNebula | github.com/jfontan
>



-- 
Javier Fontán Muiños
Developer
OpenNebula - The Open Source Toolkit for Data Center Virtualization
www.OpenNebula.org | @OpenNebula | github.com/jfontan