[Maas-devel] ephemeral image debugging

[Diogo Matsubara]

Hi Scott,

thanks for these instructions, they're very useful.
There are two small corrections to the script you sent below:

On Thu, Dec 13, 2012 at 12:35 PM, Scott Moser <smoser at ubuntu.com> wrote:

> Hey all,
>
> Whenever people have problems with enlistment or commissioning, often
> times debugging from within the ephemeral image is needed to see whats
> going on.
>
> Below is a general "how to get around" guide.
>
> ### backdoor (add a login) to ephemeral images ###
> # If you cannot login to an instance, you might have to "backdoor it"
> # in order to see what is going wrong.  I wrote a simple utility
> # that injects a user and password into an image.  Heres how to
> # add a 'backdoor' user with a password to your images.
> bzr branch lp:~smoser/+junk/backdoor-image
> imgs=$(echo var/lib/maas/ephemeral/*/*/*/*/*.img)
> for img in $imgs; do
>   [ -f "$img.dist" ] || cp -a --sparse=always $img.dist
> done
>

I assume you wanted to make a backup copy of the original image files. The
cp command is missing an argument though:

   [ -f "$img.dist" ] || cp -a --sparse=always $img $img.dist

Is that the original intention?


for img in $imgs; do
>   sudo ./backdoor-image -v --user=backdoor --password-auth
> --password=ubuntu
> done
>

Likewise here:
  sudo ./backdoor-image -v --user=backdoor --password-auth
--password=ubuntu $img



>
> ### Inside the ephemeral image  ###
>
> ## Important files for debugging:
> # Someone is likely to ask you for these things to help debug
> /var/log/cloud-init.log
> /var/log/boot.log
> /var/log/cloud-init-output.log
>
> # After enlistment or commissioning, the user-data from maas instructs
> # the system to poweroff.  To stop that from happening, you can just
> # touch a file in /tmp.
> touch /tmp/block-poweroff
>
> ## maas credentials:
> # maas credentials can be found in 2 places:
> # * from the cmdline you'll see a 'url=' or 'cloud-config-url=' parameter
> #   You can get the cloud-config from that url, which will have
> #   credentials.
> #   example:
> #    $ sed -n 's,.*url=\([^ ]*\).*,\1,p' /proc/cmdline
> #
> http://10.55.60.194/MAAS/metadata/latest/enlist-preseed/?op=get_enlist_preseed
> # * from /etc/cloud/cloud.cfg.d/91_kernel_cmdline_url
> #   The file was pulled from url= parameter by cloud-init
> #   $ sudo cat /etc/cloud/cloud.cfg.d/91_kernel_cmdline
>
> ### maas datasource ###
> # the cloud-init datasource for MAAS can be invoked as a 'main' for
> # debugging purposes. To do so, you need to know the url for the maas
> # datasource and a config file that contains credentials.
> #
> $ cfg=$(echo /etc/cloud/cloud.cfg.d/*_cmdline_url.cfg)
> $ echo $cfg
> /etc/cloud/cloud.cfg.d/91_kernel_cmdline_url.cfg
>
> # now get the metadata_url from there.
> $ url=$(sudo awk '$1 == "metadata_url:" { print $2 }' $cfg)
> $ echo $url
> http://10.55.60.194/MAAS/metadata/enlist
>
> # invoke the client
> # /usr/share/pyshared/cloudinit/sources/DataSourceMAAS.py
> # the client has --help Usage also, but here is an example on how
> # to use it.
> $ maasds="/usr/share/pyshared/cloudinit/sources/DataSourceMAAS.py"
> $ sudo python $maasds --config=$cfg get $url
> == http://10.55.60.194/MAAS/metadata/enlist ==
> 2012-03-01
> latest
>
> $ sudo python $maasds --config=$cfg get
> $url/latest/meta-data/local-hostname
> maas-enlisting-node
>
> --
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>

Cheers,
-- 
Diogo M. Matsubara
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