[jira] [Created] (AMBARI-24537) Use Mpack Instance Manager To Switch Component Instance Version on Upgrade

["Jonathan Hurley (JIRA)" <ji...@apache.org>]

Jonathan Hurley created AMBARI-24537:
----------------------------------------

             Summary: Use Mpack Instance Manager To Switch Component Instance Version on Upgrade
                 Key: AMBARI-24537
                 URL: https://issues.apache.org/jira/browse/AMBARI-24537
             Project: Ambari
          Issue Type: Task
    Affects Versions: 3.0.0
            Reporter: Jonathan Hurley
            Assignee: Jonathan Hurley
             Fix For: 3.0.0


Mpacks will not continue use the {{stack-select}} tools which have been used by various stacks over the past few years. Previously, each stack shipped a tool which would manipulate the symlinks on the file system in order to both report versions for components and to change versions during an upgrade.

The following pieces were required for this old framework:
- A file, such as {{stack_packages.json}} which provided a mapping between Ambari's component name and the symlink name on the file system.
- Each component's Python file would need code which flips the version before restarting during an upgrade:
{code}
  def pre_upgrade_restart(self, env, upgrade_type=None):
    if params.version and check_stack_feature(StackFeature.ROLLING_UPGRADE, format_stack_version(params.version)):
      stack_select.select_packages(params.version)
{code}

Mpacks v2 will instead use the mpack instance manager to change the pointer on the file system:
{noformat}
/usr/hwx/mpacks
└── hdpcore
    ├── 1.0.0-b575
    │   ├── zookeeper_client -> /usr/hwx/modules/zookeeper_clients/3.4.0.0-b42
    │   └── zookeeper_server -> /usr/hwx/modules/zookeeper/3.4.0.0-b42
    └── 1.0.0-b580
        ├── zookeeper_client -> /usr/hwx/modules/zookeeper_clients/3.4.0.0-b43
        └── zookeeper_server -> /usr/hwx/modules/zookeeper_clients/3.4.0.0-b43
{noformat}

{noformat}
/usr/hwx/instances
└── hdpcore
    └── HDPCORE
        └── default
            ├── zookeeper
            │   └── zookeeper_server
            │       └── ZK-1
            │           ├── current -> /usr/hwx/mpacks/hdpcore/1.0.0-b575/zookeeper_server
            └── zookeeper_client
                ├── current -> /usr/hwx/mpacks/hdpcore/1.0.0-b575/zookeeper_client
{noformat}

For each instance of a component, there is a {{current}} pointer which references the mpack (and indirectly) the module version. However, Ambari knows all of this information up front since it's all based on metadata contained with the {{mpack.json}}. Therefore, it is possible for Ambari to do all of this version linking inside of its own framework during the upgrade. The individual Python scripts will no longer have to perform these actions.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)