diskimage-builder/elements/dynamic-login/README.rst
Lucas Alvares Gomes 40197fa7f1 Follow up patch for 25d3ee5471
This patch is a follow up patch fixing some nits left by the review
25d3ee5471.

It does:

* Fix the README file to say that the password *must* be encrypted and
  the option values *must* be quoted

* Adds Type=oneshot in the upstart service config file so that upstart
  will not try to restart the service over and over.

* Enable setu, sete and setpipefail in the dynamic-login script

Change-Id: Iee5d75daef24469ccf47ca12de6ead37bf9d8d6f
2015-12-01 14:11:40 +00:00

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=============
dynamic-login
=============
This element insert a helper script in the image that allows users to
dynamically configure credentials at boot time. This is specially useful
for troubleshooting.
Troubleshooting an image can be quite hard, specially if you can not get
a prompt you can enter commands to find out what went wrong. By default,
the images (specially ramdisks) doesn't have any SSH key or password for
any user. Of course one could use the ``devuser`` element to generate
an image with SSH keys and user/password in the image but that would be
a massive security hole and very it's discouraged to run in production
with a ramdisk like that.
This element allows the operator to inject a SSH key and/or change the
root password dynamically when the image boots. Two kernel command line
parameters are used to do it:
sshkey
:Description: If the operator append sshkey="$PUBLIC_SSH_KEY" to the
kernel command line on boot, the helper script will append
this key to the root user authorized_keys.
rootpwd
:Description: If the operator append rootpwd="$ENCRYPTED_PASSWORD" to the
kernel command line on boot, the helper script will set the
root password to the one specified by this option. Note that
this password must be **encrypted**. Encrypted passwords
can be generated using the ``openssl`` command, e.g:
*openssl passwd -1*.
.. note::
The value of these parameters must be **quoted**, e.g: sshkey="ssh-rsa
BBBA1NBzaC1yc2E ..."
.. warning::
Some base operational systems might require selinux to be in
**permissive** or **disabled** mode so that you can log in
the image. This can be achieved by building the image with the
``selinux-permissive`` element for diskimage-builder or by passing
``selinux=0`` in the kernel command line. RHEL/CentOS are examples
of OSs which this is true.