Oracle Big Data Appliance Node Migration Frequently Asked Questions (FAQ)
(Doc ID 1946287.1)
Last updated on JULY 17, 2023
Applies to:
Big Data Appliance Integrated Software - Version 4.0 and laterLinux x86-64
Purpose
This document provides answers to frequently asked node migration questions on Oracle Big Data Appliance (BDA).
Questions and Answers
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In this Document
| Purpose |
| Questions and Answers |
| What is the expectation on a Hadoop cluster with regards to Hardware/Software resiliency? |
| What is the minimum BDA cluster size for node migration or reprovision? |
| Is the process for migrating services from a critical BDA server to another node automatic? |
| Where are critical services migrated to? |
| Is it possible to select the noncritical node the services from a failing/failed node are moved to? |
| Is it mandatory to remove/decommission any non BDA nodes from the Cluster prior to migration/reprovision? |
| What should be done if the steps to reprovision a non-critical BDA node are done out of order and decommission was skipped and reimage done first? |
| After decommissioning a node it shows up on the QUARANTINED lists in the /opt/oracle/bda/install/state/config.json file. What should those look like post-decommission? |
| When performing node migration on Node 1 can you select any noncritical node to install Mammoth on and take over the Node 1 role? |
| Could all 4 critical nodes be migrated to the same noncritical node? |
| When you migrate a critical node to a noncritical node is it possible to get overcommit violations? |
| What about cases where Nodes 1-4 are configured with additional CPU and memory but now the services are migrated to another node? |
| Why does a noncritical node need to be decommissioned with: bdacli admin_cluster decommission node-name? |
| When a node is migrated does its name or IP address change? |
| When a critical node has its services migrated to another node will that new address need to be broadcast to users? |
| Can Cloudera Manager be moved directly from Node 3 to another node? |
| Is there any impact to client or edge servers after critical services are migrated? |
| Based on the above is it correct that Mammoth automatically upgrades client configurations? |
| What about services not managed by Mammoth? When a critical node has its services migrated will those services be migrated too? |
| If the Sentry Service was enabled with Mammoth, is there anything special to do during node migration? |
| What happens if the Sentry Service was not enabled with Mammoth? What needs to be done on node migration? |
| If the keytrustee service was added with Mammoth are there any special steps to take during migration? |
| If the Key Trustee Servers are off the BDA but CM managed is there any impact on Node migration? |
| Will node migration result in any changes in private keys or trust stores or impact renewed certificates? |
| When migrating Node 3 will the migration replicate the MySQL datbase from Node 2 and all configuration files? |
| In the case of BDD being located on Node 5, will migrating Node 4 migrate the Node 4 roles to Node 5? Or will they be migrated to Node 6? |
| Before migration is it required to remove the HBase role from the cluster? |
| What about critical services configured on a non-critical node? |
| After migrating a critical node is it mandatory to migrate it back to it's original configuration? |
| After migrating a critical node can the cluster be restored to the original configuration where critical services reside on nodes 1-4 in the case of a single rack? |
| Does node migration handle the case of all 4 critical nodes going down at once? |
| What about cases of nodes 1/2, 2/3, 3/4 failing together? Do the scripts handle this case? |
| What about an Oracle NoSQL DB BDA cluster. Can those nodes be migrated as well? |
| What about Kerberos? Can nodes be migrated in secure clusters? |
| What about downtime? What is expected during node migration, reprovision, etc.? |
| Is it ok to remove the /opt/oracle/bda/network.json or rack-network.json/cluster-network.json from a reimaged node which will be reprovisioned? |
| When a node is reprovisioned, is there any password requirement? |
| If the Mammoth script fails during migration, can you back out the changes? |
| Node 1 Migration/Reprovision with CDH 5.5.2 Q/A |
| In the case of migrating Node 1 on BDA V4.4 cluster with CDH 5.5.2 are there any special considerations? |
| In the case of subsequent Node 1 reprovision on a BDA 4.4 cluster with CDH 5.5.2 are there any special considerations? |
| Can you get a new Server, off BDA, move the Mammoth 4.4 bundle there and migrate the Node 1 functionality there instead of to Node 5 ? |
| During migration what services are migrated and what services are not migrated ? |
| On BDA V4.5 what are the general steps to follow if a non-critical server needs to be reprovisioned, due to requiring a reimage. |
| On BDA V4.5 do you need to apply patch 23763068 before node migration/reprovision/etc? |
| Is it possible to move some critical roles from the critical nodes 1-4 to another node? |
| In the case of migrating the roles for multiple critical hosts is there any recommended order of migration? |
| In the case of migrating the roles for multiple critical hosts as described above what is the recommended method for performing multiple migrations? |
| How many steps are there migrating the host with CM role, Node 3 by default? |
| Does node recommission have any downtime? |
| Can the NameNode(NN) ID and ResourceManager(RM) ID used by Cloudera Manager(CM) be retained in the case of a node migration? |
| Can the RM ID be restored if the RM role is migrated back to the original host? Or will any action be able to restore the original Resource Manager ID? |
| References |