system-config/doc/source/letsencrypt.rst
Clark Boylan e66eeb8c3c Remove most linaro cloud resources
This removes ansible configuration for the linaro cloud itself and the
linaro cloud mirror. This cloud is in the process of going away and
having these nodes in our inventory is creating base jobs failures due
to unreachable nodes. This then dominoes into not running the LE refresh
job and now some certs are not getting renewed. Clean this all up so
that the rest of our systems are happy.

Note that we don't fully clean up the idea of an unmanaged group as
there may be other locations we want to do something similar (OpenMetal
perhaps?). We also don't remove the openstack clouds.yaml entries for
the linaro cloud yet. It isn't entirely clear when things will go
offline, but it may be as late as August 10 so we keep those credentials
around as they may be useful until then.

Change-Id: Idd6b455de8da2aa9901bf989b1d131f1f4533420
2024-08-02 09:21:11 -07:00

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5.5 KiB
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:title: letsencrypt
.. _letsencrypt:
Let's Encrypt Certificates
##########################
We support provisioning certificates from https://letsencrypt.org for
hosts in the ``opendev.org`` namespace.
At a Glance
===========
:Ansible:
* :git_file:`playbooks/letsencrypt.yaml`
* :git_file:`playbooks/roles/letsencrypt-acme-sh-install`
* :git_file:`playbooks/roles/letsencrypt-request-certs`
* :git_file:`playbooks/roles/letsencrypt-install-txt-record`
* :git_file:`playbooks/roles/letsecnrypt-create-certs`
:Resources:
* https://letsencrypt.org
* https://github.com/Neilpang/acme.sh
:Chat:
* #opendev on OFTC
Overview
========
We support automatic provisioning of certificates from Let's Encrypt
to hosts in the ``opendev.org`` domain.
This is implemented in OpenDev via the roles driven from
:git_file:`playbooks/letsencrypt.yaml`. The overall
actions implemented by the above roles are roughly:
* Hosts that want a certificate use the ``amce.sh`` tool to request it
from the Let's Encrypt CA.
Creation or renewal requests receive a TXT record authentication
value that must be published to prove ownership of the domain. We
implement this by making the challenge-request hostname
``_acme-challenge.hostname.opendev.org`` a ``CNAME`` record to a
special "signing domain" ``acme.opendev.org``.
Note if valid certificates are present and they are not within the
renewal period (which is most of the time) no further action is
taken.
* The provided TXT record authentication values are installed and
published to the ``acme.opendev.org`` domain via the OpenDev
nameservers.
* The host can now finalise certificate creation. Let's Encrypt
checks ``_acme-chellenge.hostname.opendev.org``, which is a
``CNAME`` to ``acme.opendev.org``. Let's Encrypt then enumerates
the TXT records there, and once finding the required key will return
the signed keys to the host, which saves them to disk.
Configuring a host to get certificates
======================================
A basic configuration consists of the following steps:
1. Ensure the host is matched by the ``letsencrypt`` group in
:git_file:`inventory/groups.yaml`.
#. DNS entries for ``_acme-chellenge.hostname`` as a ``CNAME`` to
``opendev.org`` must be added and live in the ``opendev.org``
`zone.db
<https://opendev.org/opendev/zone-opendev.org/src/branch/master/zones/opendev.org/zone.db>`__
file. Follow the other examples to ensure other fields such as
``CAA`` records are set too.
Take care to list `all` hostnames that you wish covered by the
certificate (e.g. ``hostname01.opendev.org`` and
``hostname.opendev.org``)
#. Configure the certificates to be issued to the host.
The roles look for certificate configuration in a
``letsencrypt_certs`` variable defined for each host. This is
usually done via specific host variables in
``inventory/service/host_vars/<hostname>.opendev.org.yaml``. For a simple
host that wants a single certificate to cover its numeric hostname
and regular ``CNAME`` this would look like ::
letsencrypt_certs:
hostname01-opendev-org:
- hostname01.opendev.org
- hostname.opendev.org
This will result in certificate material in
``/etc/letsencrypt-certs/hostname01.opendev.org/`` on the host.
Note that the "certificate name" dictionary keys (just
``hostname01-opendev-org`` above) are essentially a free-form
string, but are used in the next step. Follow the naming
conventions for similar hosts.
For full details, including information on issuing multiple
certificates for a single host, see
:git_file:`playbooks/roles/letsencrypt-request-certs/README.rst`.
#. Define a handler for certificate creation and renewal actions.
When the certificate is created or renewed, the
``letsencrypt-create-certs`` role calls a predefined handler so
action can be taken. This handler name is constructed by
prepending ``letsencrypt updated`` to the certificate name above.
Thus in this example it would be ::
- name: letsencrypt updated hostname01-opendev-org
...
Usually these handlers are defined centrally in
:git_file:`playbooks/roles/letsencrypt-create-certs/handlers/main.yaml`
and common tasks such as restarting Apache have pre-defined tasks
available for easy import.
You may choose to define the handler in another way, but it *must*
exist (Ansible does not have a way to say "call this handler only
if it exists", thus a missing handler will cause an Ansible error
at runtime).
Debugging
=========
The Ansible run logs on ``bridge.opendev.org`` should be consulted if
the certificate material is not being created as expected.
Hosts will log their ``acme.sh`` output to
``/var/log/acme.sh/acme.sh.log``
The `G Suite Toolbox Dig <https://toolbox.googleapps.com/apps/dig/>`__
tool can be useful for checking DNS entries from a remote location.
Refreshing keys
===============
In normal operation there should be no need to manually refresh keys
on hosts. However there have been situations (such as LetsEncrypt
revoking certificates made during a certain period due to bugs) which
may necessitate a manual renewal.
The best way to do this is to move the ``.conf`` files from
``/etc/letsencrypt-certs/<certname>`` on the affected host and allow
the next Ansible pulse to renew.
.. code-block:: console
# cd /etc/letsencrypt-certs/<name>
# rename 's/.conf/.conf.old/' *.conf
# tail -f /var/log/acme.sh/acme.sh.log
... watch and should be renewed on next pulse
# rm *.conf.old