github.com/amanya/packer@v0.12.1-0.20161117214323-902ac5ab2eb6/website/source/docs/other/debugging.html.md (about)

     1  ---
     2  description: |
     3      Packer strives to be stable and bug-free, but issues inevitably arise where
     4      certain things may not work entirely correctly, or may not appear to work
     5      correctly. In these cases, it is sometimes helpful to see more details about
     6      what Packer is actually doing.
     7  layout: docs
     8  page_title: Debugging Packer
     9  ...
    10  
    11  # Debugging Packer Builds
    12  
    13  For remote builds with cloud providers like Amazon Web Services AMIs, debugging
    14  a Packer build can be eased greatly with `packer build -debug`. This disables
    15  parallelization and enables debug mode.
    16  
    17  Debug mode informs the builders that they should output debugging information.
    18  The exact behavior of debug mode is left to the builder. In general, builders
    19  usually will stop between each step, waiting for keyboard input before
    20  continuing. This will allow you to inspect state and so on.
    21  
    22  In debug mode once the remote instance is instantiated, Packer will emit to the
    23  current directory an ephemeral private ssh key as a .pem file. Using that you
    24  can `ssh -i <key.pem>` into the remote build instance and see what is going on
    25  for debugging. The key will only be emitted for cloud-based builders. The
    26  ephemeral key will be deleted at the end of the packer run during cleanup.
    27  
    28  For a local builder, the SSH session initiated will be visible in the detail
    29  provided when `PACKER_LOG=1` environment variable is set prior to a build,
    30  and you can connect to the local machine using the userid and password defined
    31  in the kickstart or preseed associated with initialzing the local VM.
    32  
    33  ### Windows
    34  
    35  As of Packer 0.8.1 the default WinRM communicator will emit the password for a
    36  Remote Desktop Connection into your instance. This happens following the several
    37  minute pause as the instance is booted. Note a .pem key is still created for
    38  securely transmitting the password. Packer automatically decrypts the password
    39  for you in debug mode.
    40  
    41  ## Debugging Packer
    42  
    43  Issues occasionally arise where certain things may not work entirely correctly,
    44  or may not appear to work correctly. In these cases, it is sometimes helpful to
    45  see more details about what Packer is actually doing.
    46  
    47  Packer has detailed logs which can be enabled by setting the `PACKER_LOG`
    48  environmental variable to any value but `""` (empty string) and `"0"` like this
    49  `PACKER_LOG=1 packer build <config.json>`. This will cause detailed logs to
    50  appear on stderr. The logs contain log messages from Packer as well as any
    51  plugins that are being used. Log messages from plugins are prefixed by their
    52  application name.
    53  
    54  Note that because Packer is highly parallelized, log messages sometimes appear
    55  out of order, especially with respect to plugins. In this case, it is important
    56  to pay attention to the timestamp of the log messages to determine order.
    57  
    58  In addition to simply enabling the log, you can set `PACKER_LOG_PATH` in order
    59  to force the log to always go to a specific file when logging is enabled. Note
    60  that even when `PACKER_LOG_PATH` is set, `PACKER_LOG` must be set in order for
    61  any logging to be enabled.
    62  
    63  ### Debugging Packer in Powershell/Windows
    64  
    65  In Windows you can set the detailed logs environmental variable `PACKER_LOG` or
    66  the log variable `PACKER_LOG_PATH` using powershell environment variables. For
    67  example:
    68  
    69      $env:PACKER_LOG=1
    70      $env:PACKER_LOG_PATH="packerlog.txt"
    71  
    72  If you find a bug with Packer, please include the detailed log by using a
    73  service such as [gist](https://gist.github.com).
    74  
    75  ## Issues Installing Ubuntu Packages
    76  
    77  Issues may arise using and building Ubuntu AMIs where common packages that
    78  *should* be installed from Ubuntu's Main repository are not found during a
    79  provisioner step:
    80  
    81      amazon-ebs: No candidate version found for build-essential
    82      amazon-ebs: No candidate version found for build-essential
    83  
    84  This, obviously can cause problems where a build is unable to finish
    85  successfully as the proper packages cannot be provisioned correctly. The problem
    86  arises when cloud-init has not finished fully running on the source AMI by the
    87  time that packer starts any provisioning steps.
    88  
    89  Adding the following provisioner to the packer template, allows for the
    90  cloud-init process to fully finish before packer starts provisioning the source
    91  AMI.
    92  
    93      {
    94        "type": "shell",
    95        "inline": [
    96          "while [ ! -f /var/lib/cloud/instance/boot-finished ]; do echo 'Waiting for cloud-init...'; sleep 1; done"
    97        ]
    98      }