Securing configs with ZooKeeper ACLs and Ranger

Learn how you can restrict access to configuration sets by setting ZooKeeper Acces control Lists (ACLs) on all znodes under and including the /solr directory and using Ranger to control access to the ConfigSets API.

Ranger requires Kerberos authentication.

The solrctl instancedir command interacts directly with ZooKeeper, and therefore cannot be protected by Ranger. Because the solrctl config command is a wrapper script for the ConfigSets API, it can be protected by Ranger.

To force users to use the ConfigSets API, you must set all ZooKeeper znodes under and including /solr to read-only (except for the solr user).

After completing these steps, you cannot run commands such as solrctl instancedir --create or solrctl instancedir --delete without first authenticating as the solr@EXAMPLE.COM super user principal. Unauthenticated users can still run solrctl instancedir --list and solrctl instancedir --get, because those commands only perform read operations against ZooKeeper.

Create a jaas.conf file containing the following:

Client {
           com.sun.security.auth.module.Krb5LoginModule required
           useKeyTab=false
           useTicketCache=true
           principal="solr@[***EXAMPLE.COM***]";
           };

Replace [***EXAMPLE.COM***] with your Kerberos realm name.

Set the LOG4J_PROPS environment variable so that it points to a log4j.properties file:
```
export LOG4J_PROPS=/etc/zookeeper/conf/log4j.properties
```

Set the ZKCLI_JVM_FLAGS environment variable:

export ZKCLI_JVM_FLAGS="-Djava.security.auth.login.config=[***PATH TO JAAS.CONF FILE***] \
             -DzkACLProvider=org.apache.solr.common.cloud.SaslZkACLProvider \
             -Droot.logger=INFO,console"

Replace

[***PATH TO
              JAAS.CONF FILE***]

with the path pointing to the jaas.conf file you just created.

Authenticate as the solr user:
```
kinit solr@[***EXAMPLE.COM***]
```
Replace [***EXAMPLE.COM***] with your Kerberos realm name.
Run the zkcli.sh script as follows:
```
/opt/cloudera/parcels/CDH/lib/solr/bin/zkcli.sh -zkhost [***ZOOKEEPER SERVER HOSTNAME***]:2181 -cmd updateacls /solr
```
Replace [***ZOOKEEPER SERVER HOSTNAME***] with the hostname of a ZooKeeper server.