tripleo-heat-templates/docker/services/README.rst
Jiri Stransky 16405ff928 Run online data migrations
We always run DB sync in deploy_tasks, ensuring that the database is
up to date. We should follow up with online data migrations
too.

Doing this via docker_config has 2 purposes:

* We can easily ensure this happens in a container with the right
  config files mounted.

* We can even apply this via a minor update. This is important because
  we'll have to backport this all the way to Pike and apply it there
  using Pike containers, before upgrading to Queens containers.

There's an additional issue to consider: In Puppet service variant we
ran the online migrations for release X before upgrading to X+1, but
the proposed Docker variant migrations for X run with upgrade to
X. This means that when switching from non-containerized to
containerized, we'll need to run migrations twice, to correctly switch
between the aforementioned approaches.

Change-Id: I2eb6c7c42d7e7aea4a78a892790e42bc5371f792
Closes-Bug: #1790474
2018-09-04 15:42:33 +02:00

177 lines
7.1 KiB
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===============
Docker Services
===============
TripleO docker services are currently built on top of the puppet services.
To do this each of the docker services includes the output of the
t-h-t puppet/service templates where appropriate.
In general global docker specific service settings should reside in these
templates (templates in the docker/services directory.) The required and
optional items are specified in the docker settings section below.
If you are adding a config setting that applies to both docker and
baremetal that setting should (so long as we use puppet) go into the
puppet/services templates themselves.
Also see the
`Puppet services README file <https://github.com/openstack/tripleo-heat-templates/blob/master/puppet/services/README.rst>`_
for more information about how the service templates work in general.
Building Kolla Images
---------------------
TripleO currently relies on Kolla docker containers. Kolla supports container
customization and we are making use of this feature within TripleO to inject
puppet (our configuration tool of choice) into the Kolla base images. The
undercloud nova-scheduler also requires openstack-tripleo-common to
provide custom filters.
To build Kolla images for TripleO adjust your kolla config [*]_ to build your
centos base image with puppet using the example below:
.. code-block::
$ cat template-overrides.j2
{% extends parent_template %}
{% set base_centos_binary_packages_append = ['puppet'] %}
{% set nova_scheduler_packages_append = ['openstack-tripleo-common'] %}
kolla-build --base centos --template-override template-overrides.j2
..
.. [*] See the
`override file <https://github.com/openstack/tripleo-common/blob/master/contrib/tripleo_kolla_template_overrides.j2>`_
which can be used to build Kolla packages that work with TripleO, and an
`example build script <https://github.com/dprince/undercloud_containers/blob/master/build_kolla.sh>_.
Docker settings
---------------
Each service may define an output variable which returns a puppet manifest
snippet that will run at each of the following steps. Earlier manifests
are re-asserted when applying latter ones.
* config_settings: This setting is generally inherited from the
puppet/services templates and only need to be appended
to on accasion if docker specific config settings are required.
* kolla_config: Contains YAML that represents how to map config files
into the kolla container. This config file is typically mapped into
the container itself at the /var/lib/kolla/config_files/config.json
location and drives how kolla's external config mechanisms work.
* docker_config: Data that is passed to the docker-cmd hook to configure
a container, or step of containers at each step. See the available steps
below and the related docker-cmd hook documentation in the heat-agents
project.
* puppet_config: This section is a nested set of key value pairs
that drive the creation of config files using puppet.
Required parameters include:
* puppet_tags: Puppet resource tag names that are used to generate config
files with puppet. Only the named config resources are used to generate
a config file. Any service that specifies tags will have the default
tags of 'file,concat,file_line,augeas,cron' appended to the setting.
Example: keystone_config
* config_volume: The name of the volume (directory) where config files
will be generated for this service. Use this as the location to
bind mount into the running Kolla container for configuration.
* config_image: The name of the docker image that will be used for
generating configuration files. This is often the same container
that the runtime service uses. Some services share a common set of
config files which are generated in a common base container.
* step_config: This setting controls the manifest that is used to
create docker config files via puppet. The puppet tags below are
used along with this manifest to generate a config directory for
this container.
* docker_puppet_tasks: This section provides data to drive the
docker-puppet.py tool directly. The task is executed only once
within the cluster (not on each node) and is useful for several
puppet snippets we require for initialization of things like
keystone endpoints, database users, etc. See docker-puppet.py
for formatting.
Docker steps
------------
Similar to baremetal docker containers are brought up in a stepwise manner.
The current architecture supports bringing up baremetal services alongside
of containers. For each step the baremetal puppet manifests are executed
first and then any docker containers are brought up afterwards.
Steps correlate to the following:
Pre) Containers config files generated per hiera settings.
1) Load Balancer configuration baremetal
a) step 1 baremetal
b) step 1 containers
2) Core Services (Database/Rabbit/NTP/etc.)
a) step 2 baremetal
b) step 2 containers
3) Early Openstack Service setup (Ringbuilder, etc.)
a) step 3 baremetal
b) step 3 containers
4) General OpenStack Services
a) step 4 baremetal
b) step 4 containers
c) Keystone containers post initialization (tenant,service,endpoint creation)
5) Service activation (Pacemaker), online data migration
a) step 5 baremetal
b) step 5 containers
Update steps:
-------------
All services have an associated update_tasks output that is an ansible
snippet that will be run during update in an rolling update that is
expected to run in a rolling update fashion (one node at a time)
For Controller (where pacemaker is running) we have the following states:
1. Step=1: stop the cluster on the updated node;
2. Step=2: Pull the latest image and retag the it pcmklatest
3. Step=3: yum upgrade happens on the host.
4. Step=4: Restart the cluster on the node
5. Step=5: Verification:
Currently we test that the pacemaker services are running.
Then the usual deploy steps are run which pull in the latest image for
all containerized services and the updated configuration if any.
Note: as pacemaker is not containerized, the points 1 and 4 happen in
puppet/services/pacemaker.yaml.
Fast-forward Upgrade Steps
--------------------------
Each service template may optionally define a `fast_forward_upgrade_tasks` key,
which is a list of Ansible tasks to be performed during the fast-forward
upgrade process. As with Upgrade steps each task is associated to a particular
step provided as a variable and used along with a release variable by a basic
conditional that determines when the task should run.
Steps are broken down into two categories, prep tasks executed across all hosts
and bootstrap tasks executed on a single host for a given role.
The individual steps then correspond to the following tasks during the upgrade:
Prep steps:
- Step=0: Check running services
- Step=1: Stop the service
- Step=2: Stop the cluster
- Step=3: Update repos
Bootstrap steps:
- Step=4: DB backups
- Step=5: Pre package update commands
- Step=6: Package updates
- Step=7: Post package update commands
- Step=8: DB syncs
- Step=9: Verification