[AMBARI-17796] Ranger Admin Fails To Stop Or Start During Downgrade From HDP 2.5 to HDP 2.4

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 2.4.0
• Fix Version/s: 2.4.0
• Component/s: ambari-server
• Assignee: Jonathan Hurley
• Reporter: Jonathan Hurley
• Created: 19/Jul/16 18:32
• Updated: 20/Jul/16 00:16
• Resolved: 19/Jul/16 21:08

Description

Steps

1. Deploy HDP-2.4.
2. Perform EU to 2.5.0.0-995 (or 2.5.0.0-1016) until finalize step
3. Downgrade back to 2.4.2

Observed below errors while stopping all components

Traceback (most recent call last):
  File \"/var/lib/ambari-agent/cache/common-services/RANGER/0.4.0/package/scripts/ranger_admin.py\", line 199, in <module>
    RangerAdmin().execute()
  File \"/usr/lib/python2.6/site-packages/resource_management/libraries/script/script.py\", line 280, in execute
    method(env)
  File \"/var/lib/ambari-agent/cache/common-services/RANGER/0.4.0/package/scripts/ranger_admin.py\", line 60, in stop
    import params
  File \"/var/lib/ambari-agent/cache/common-services/RANGER/0.4.0/package/scripts/params.py\", line 176, in <module>
    audit_jdbc_url = format('jdbc:postgresql://{db_host}/{ranger_auditdb_name}') if stack_supports_ranger_audit_db else None
  File \"/usr/lib/python2.6/site-packages/resource_management/libraries/functions/format.py\", line 95, in format
    return ConfigurationFormatter().format(format_string, args, **result)
  File \"/usr/lib/python2.6/site-packages/resource_management/libraries/functions/format.py\", line 59, in format
    result_protected = self.vformat(format_string, args, all_params)
  File \"/usr/lib/python2.7/string.py\", line 549, in vformat
    result = self._vformat(format_string, args, kwargs, used_args, 2)
  File \"/usr/lib/python2.7/string.py\", line 582, in _vformat
    result.append(self.format_field(obj, format_spec))
  File \"/usr/lib/python2.7/string.py\", line 599, in format_field
    return format(value, format_spec)
  File \"/usr/lib/python2.6/site-packages/resource_management/libraries/script/config_dictionary.py\", line 73, in __getattr__
    raise Fail(\"Configuration parameter '\" + self.name + \"' was not found in configurations dictionary!\")
resource_management.core.exceptions.Fail: Configuration parameter 'audit_db_name' was not found in configurations dictionary!

Other components fail as well in a similar manner (if they use Ranger).

This is a specific issues on an EU downgrade from 2.5 to 2.4. Here's the scenario:

• Ranger supported "Audit to DB" up to HDP 2.5. It was removed in HDP 2.5. Along with it, the properties in admin-properties were removed as well.
• The Ranger params.py uses the check_stack_feature to determine if "Audit to DB" is supported and if it is, tries to extract the properties it needs.

All is well and good at this point. The problem comes when a downgrade happens.

• When downgrading from 2.5 to 2.4 the 2.4 configurations should be restored. However, this doesn't happen on an EU until after the STOP command is issued for upgraded services. It's during this STOP command that we run into an issue. Ranger is running on 2.5, so the 2.5 configurations are sent to stop it. However, the version that we're downgrading to is 2.4, so it thinks that it needs to extract the audit properties.

• On the RESTART of Ranger on the downgrade, it should be extracting the audit properties since the 2.4 configurations are sent. But the STOP command is for 2.5 and doesn't have them.

So, this means that STOP and RESTART are using different configurations on an EU downgrade. We basically need to create a way to reliably determine which stack version should be used for feature checks.

Issue Links

• links to: Reviewboard