github.com/phobos182/packer@v0.2.3-0.20130819023704-c84d2aeffc68/website/source/docs/provisioners/shell.html.markdown (about)

     1  ---
     2  layout: "docs"
     3  ---
     4  
     5  # Shell Provisioner
     6  
     7  Type: `shell`
     8  
     9  The shell provisioner provisions machines built by Packer using shell scripts.
    10  Shell provisioning is the easiest way to get software installed and configured
    11  on a machine.
    12  
    13  ## Basic Example
    14  
    15  The example below is fully functional.
    16  
    17  <pre class="prettyprint">
    18  {
    19    "type": "shell",
    20    "inline": ["echo foo"]
    21  }
    22  </pre>
    23  
    24  ## Configuration Reference
    25  
    26  The reference of available configuration options is listed below. The only
    27  required element is either "inline" or "script". Every other option is optional.
    28  
    29  Exactly _one_ of the following is required:
    30  
    31  * `inline` (array of strings) - This is an array of commands to execute.
    32    The commands are concatenated by newlines and turned into a single file,
    33    so they are all executed within the same context. This allows you to
    34    change directories in one command and use something in the directory in
    35    the next and so on. Inline scripts are the easiest way to pull of simple
    36    tasks within the machine.
    37  
    38  * `script` (string) - The path to a script to upload and execute in the machine.
    39    This path can be absolute or relative. If it is relative, it is relative
    40    to the working directory when Packer is executed.
    41  
    42  * `scripts` (array of strings) - An array of scripts to execute. The scripts
    43    will be uploaded and executed in the order specified. Each script is executed
    44    in isolation, so state such as variables from one script won't carry on to
    45    the next.
    46  
    47  Optional parameters:
    48  
    49  * `environment_vars` (array of strings) - An array of key/value pairs
    50    to inject prior to the execute_command. The format should be
    51    `key=value`. Packer injects some environmental variables by default
    52    into the environment, as well, which are covered in the section below.
    53  
    54  * `execute_command` (string) - The command to use to execute the script.
    55    By default this is `chmod +x {{ .Path }}; {{ .Vars }} {{ .Path }}`. The value of this is
    56    treated as [configuration template](/docs/templates/configuration-templates.html). There are two available variables: `Path`, which is
    57    the path to the script to run, and `Vars`, which is the list of
    58    `environment_vars`, if configured.
    59  
    60  * `inline_shebang` (string) - The
    61    [shebang](http://en.wikipedia.org/wiki/Shebang_(Unix)) value to use when
    62    running commands specified by `inline`. By default, this is `/bin/sh`.
    63    If you're not using `inline`, then this configuration has no effect.
    64  
    65  * `remote_path` (string) - The path where the script will be uploaded to
    66    in the machine. This defaults to "/tmp/script.sh". This value must be
    67    a writable location and any parent directories must already exist.
    68  
    69  * `start_retry_timeout` (string) - The amount of time to attempt to
    70    _start_ the remote process. By default this is "5m" or 5 minutes. This
    71    setting exists in order to deal with times when SSH may restart, such as
    72    a system reboot. Set this to a higher value if reboots take a longer
    73    amount of time.
    74  
    75  ## Execute Command Example
    76  
    77  To many new users, the `execute_command` is puzzling. However, it provides
    78  an important function: customization of how the command is executed. The
    79  most common use case for this is dealing with **sudo password prompts**.
    80  
    81  For example, if the default user of an installed operating system is "packer"
    82  and has the password "packer" for sudo usage, then you'll likely want to
    83  change `execute_command` to be:
    84  
    85  ```
    86  "echo 'packer' | {{ .Vars }} sudo -E -S sh '{{ .Path }}'"
    87  ```
    88  
    89  The `-S` flag tells `sudo` to read the password from stdin, which in this
    90  case is being piped in with the value of "packer". The `-E` flag tells `sudo`
    91  to preserve the environment, allowing our environmental variables to work
    92  within the script.
    93  
    94  By setting the `execute_command` to this, your script(s) can run with
    95  root privileges without worrying about password prompts.
    96  
    97  ## Default Environmental Variables
    98  
    99  In addition to being able to specify custom environmental variables using
   100  the `environmental_vars` configuration, the provisioner automatically
   101  defines certain commonly useful environmental variables:
   102  
   103  * `PACKER_BUILD_NAME` is set to the name of the build that Packer is running.
   104    This is most useful when Packer is making multiple builds and you want to
   105    distinguish them slightly from a common provisioning script.
   106  
   107  * `PACKER_BUILDER_TYPE` is the type of the builder that was used to create
   108    the machine that the script is running on. This is useful if you want to
   109    run only certain parts of the script on systems built with certain builders.
   110  
   111  ## Handling Reboots
   112  
   113  Provisioning sometimes involves restarts, usually when updating the operating
   114  system. Packer is able to tolerate restarts via the shell provisioner.
   115  
   116  Packer handles this by retrying to start scripts for a period of time
   117  before failing. This allows time for the machine to start up and be ready
   118  to run scripts. The amount of time the provisioner will wait is configured
   119  using `start_retry_timeout`, which defaults to a few minutes.
   120  
   121  Sometimes, when executing a command like `reboot`, the shell script will
   122  return and Packer will start executing the next one before SSH actually
   123  quits and the machine restarts. For this, put a long `sleep` after the
   124  reboot so that SSH will eventually be killed automatically:
   125  
   126  ```
   127  reboot
   128  sleep 60
   129  ```