HDDS-14249. Add ozone.scm.names fallback for SCM client addresses

[sreejasahithi]

What changes were proposed in this pull request?

OzoneManager fails to start in non-HA mode when the following minimal config is used

  <property>
    <name>ozone.scm.names</name>
    <value>host1</value>
  </property>
  <property>
    <name>ozone.om.address</name>
    <value>host1:9862</value>
  </property>
  <property>
    <name>ozone.metadata.dirs</name>
    <value>/data/ozone/meta</value>
  </property> 

Error: ERROR om.OzoneManager: Could not initialize OM version filejava.io.IOException: Failed to get SCM info
Root Cause:
In non-HA mode, SCMNodeInfo.buildNodeInfo() resolves addresses using configuration fallback chains. The fallback chains do not include ozone.scm.names as a final fallback option so when only ozone.scm.names was configured (without explicit ozone.scm.client.address or ozone.scm.block.client.address), these lookups returned null, causing OzoneManager initialization to fail.

This fix adds ozone.scm.names as the final fallback for scmBlockClientAddress, scmClientAddress, scmSecurityClientAddress

What is the link to the Apache JIRA

HDDS-14249

How was this patch tested?

This patch was tested locally on a docker non-ha cluster.

Green CI : https://github.com/sreejasahithi/ozone/actions/runs/20706673375

[cchung100m]

LGTM, thanks to @sreejasahithi

[sarvekshayr]

Thanks @sreejasahithi for working on this.

The JIRA description mentions that the issue was resolved after explicitly setting both ozone.scm.client.address and ozone.scm.datanode.address.
However, ozone.scm.datanode.address already falls back to om.scm.names. Why was it still necessary to set it explicitly in this case?
cc: @ssulav

[sreejasahithi]

Thanks @sreejasahithi for working on this.

The JIRA description mentions that the issue was resolved after explicitly setting both ozone.scm.client.address and ozone.scm.datanode.address. However, ozone.scm.datanode.address already falls back to om.scm.names. Why was it still necessary to set it explicitly in this case? cc: @ssulav

It wasn't necessary to explicitly set ozone.scm.datanode.address for OM to stop failing. In non-HA mode, datanodes directly use ozone.scm.names via HddsServerUtil.getSCMAddressForDatanodes()

[sadanand48]

LGTM, Thanks @sreejasahithi for the patch

[adoroszlai]

Thanks @sreejasahithi for the patch.

[adoroszlai]

Thanks @sreejasahithi for the patch, @cchung100m, @sadanand48, @sarvekshayr for the review.