Download Solr configuration from HDP Search ZooKeeper

The solr-download-metadata.sh script downloads metadata from HDP Search ZooKeeper. You can then copy this information into a CDP cluster and use it as input for the to CDP Private Cloud Base upgrade process.

Copy the migration script to any of the nodes in the cluster where HDP Search is deployed.
The migration script uses jq for JSON file processing, this tool has to be installed.
For example, yum install jq

Set the JAVA_HOME environment variable to the JDK location. For example:
```
export JAVA_HOME=/usr/jdk64/jdk1.8.0_112
```
Add java to PATH. For example:
```
 export PATH=$PATH:$JAVA_HOME/bin
```
On a host running Solr server, set the SOLR_ZK_ENSEMBLE environment variable:
```
export SOLR_ZK_ENSEMBLE=[***HOSTNAME***]:2181/solr
```
Replace [***HOSTNAME***] with a value that is valid in your environment.
On a host running Solr server, set the SOLR_ADMIN_URI environment variable:
```
export SOLR_ADMIN_URI=[***HOSTNAME***]:8983/solr
```
Replace [***HOSTNAME***] with an actual value that is valid in your environment. Make sure that you include the protocol (HTTP or HTTPS) and do not include a trailing slash (/).
For example:
```
export SOLR_ADMIN_URI=htp://example.com:8983/solr
```
On a secure cluster you may need to set additional zkcli flags, for instance:
```
export ZKCLI_JVM_FLAGS="-Djava.security.auth.login.config=[***/PATH/TO/JAAS.CONF***]"
```
Replace [***/PATH/TO/JAAS.CONF***] with path to a valid jaas.conf file.
If you have enabled Kerberos, run the kinit command with the Solr service superuser. For example:
```
kinit solr@[***EXAMPLE.COM***]
```
Replace [***EXAMPLE.COM***] with your Kerberos realm name.
Download the current (HDP Search 2 or 3) Solr configuration from ZooKeeper:
- ```
solr-download-metadata.sh [***DIRECTORY***]
```
  Replace [***DIRECTORY***] with the path to the directory where you want to download the Solr configuration.
- If you have enabled Kerberos and configured ZooKeeper Access Control Lists (ACLs), specify your JAAS configuration file by adding the --jaas parameter to the command.
```
solr-download-metadata.sh --jaas [***/PATH/TO/JAAS.CONF***] [***DIRECTORY***]
```
  Replace [***/PATH/TO/JAAS.CONF***] with the path to a valid jaas.conf file.
  
  Replace [***DIRECTORY***] with the path to the directory where you want to download the Solr configuration.
In case of a successful run, the last line printed out by the script is:
Successfully downloaded SOLR metadata from Zookeeper
note
Make a backup copy of the downloaded configuration.
Copy the migrated data to $HOME/cr7-solr-migration in the interim Solr instance.
Initialize a directory for the migrated configuration as a copy of the current configuration:
cp -r $HOME/cr7-solr-migration $HOME/cr7-migrated-solr-config