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Diffstat (limited to 'puppet/services/README.rst')
| -rw-r--r-- | puppet/services/README.rst | 53 |
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 ----------------------------- |