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-rw-r--r--puppet/services/README.rst53
1 files changed, 47 insertions, 6 deletions
diff --git a/puppet/services/README.rst b/puppet/services/README.rst
index 6e4e9c1d..223c3ed0 100644
--- a/puppet/services/README.rst
+++ b/puppet/services/README.rst
@@ -19,8 +19,21 @@ environment to set per service parameters.
Config Settings
---------------
-Each service may define a config_settings output variable which returns
-Hiera settings to be configured.
+Each service may define three ways in which to output variables to configure Hiera
+settings on the nodes.
+
+ * config_settings: the hiera keys will be pushed on all roles of which the service
+ is a part of.
+
+ * global_config_settings: the hiera keys will be distributed to all roles
+
+ * service_config_settings: Takes an extra key to wire in values that are
+ defined for a service that need to be consumed by some other service.
+ For example:
+ service_config_settings:
+ haproxy:
+ foo: bar
+ This will set the hiera key 'foo' on all roles where haproxy is included.
Deployment Steps
----------------
@@ -49,6 +62,32 @@ are re-asserted when applying latter ones.
5) Service activation (Pacemaker)
+Batch Upgrade Steps
+-------------------
+
+Each service template may optionally define a `upgrade_batch_tasks` key, which
+is a list of ansible tasks to be performed during the upgrade process.
+
+Similar to the step_config, we allow a series of steps for the per-service
+upgrade sequence, defined as ansible tasks with a tag e.g "step1" for the first
+step, "step2" for the second, etc (currently only two steps are supported, but
+more may be added when required as additional services get converted to batched
+upgrades).
+
+Note that each step is performed in batches, then we move on to the next step
+which is also performed in batches (we don't perform all steps on one node,
+then move on to the next one which means you can sequence rolling upgrades of
+dependent services via the step value).
+
+The tasks performed at each step is service specific, but note that all batch
+upgrade steps are performed before the `upgrade_tasks` described below. This
+means that all services that support rolling upgrades can be upgraded without
+downtime during `upgrade_batch_tasks`, then any remaining services are stopped
+and upgraded during `upgrade_tasks`
+
+The default batch size is 1, but this can be overridden for each role via the
+`upgrade_batch_size` option in roles_data.yaml
+
Upgrade Steps
-------------
@@ -65,15 +104,17 @@ step, "step2" for the second, etc.
2) Stop all control-plane services, ready for upgrade
- 3) Perform a package update, (either specific packages or the whole system)
+ 3) Perform a package update and install new packages: A general
+ upgrade is done, and only new package should go into service
+ ansible tasks.
4) Start services needed for migration tasks (e.g DB)
5) Perform any migration tasks, e.g DB sync commands
- 6) Start control-plane services
-
- 7) Any additional online migration tasks (e.g data migrations)
+Note that the services are not started in the upgrade tasks - we instead re-run
+puppet which does any reconfiguration required for the new version, then starts
+the services.
Nova Server Metadata Settings
-----------------------------