Apache ZooKeeper ACLs
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ZooKeeper ACLs Best Practices: Ranger KMS/Hadoop KMS

You must follow the best practices for tightening the ZooKeeper ACLs or permissions for Ranger KMS/Hadoop KMS when provisioning a secure cluster.

  • ZooKeeper Usage:
    • If multiple instances of KMS are configured, both Ranger KMS and Hadoop KMS use zookeeper znode /hadoop-kms to store HTTP cookie signature secret. See “Http Authentication Signature” section here.

      /hadoop-kms - <HTTP cookie signature secret>

  • Default ACLs:
    • /hadoop-kms - world:anyone:cdrwa

  • Security Best Practice ACLs/Permissions and Required Steps:
    • /hadoop-kms - sasl:rangerkms:cdrwa

    • Ranger KMS uses the user rangerkms. Only KMS needs access to this znode. This path (hadoop.kms.authentication.signer.secret.provider.zookeeper.path) can be configured in Ambari for Ranger KMS. Set the ACL using these steps:
      1. SSH to the cluster where Ranger KMS is present.

      2. Go to /usr/hdp/<version>/zookeeper/bin

      3. Run ./zkCli.sh -server <FQDN of Ranger KMS host>:2181”

      4. After it connects, run: ls /

      5. Verify there is a folder as specified in hadoop.kms.authentication.signer.secret.provider.zookeeper.path property of Ranger KMS configuration.

      6. Execute getAcl /hadoop-kms and if the permission is for world,anyone: cdrwa, restrict the permission to sasl:rangerkms:cdrwa using this command: setAcl /hadoop-kms sasl:rangerkms:cdrwa.

      7. Repeat the above step for all the clusters where Ranger KMS is installed.

      [zk: dk-test-0706-3.openstacklocal:2181(CONNECTED) 0] getAcl /hadoop-kms
      : cdrwa
      [zk: dk-test-0706-3.openstacklocal:2181(CONNECTED) 4] setAcl /hadoop-kms sasl:rangerkms:cdrwa
      cZxid = 0x20000001e
      ctime = Tue Jun 07 12:22:58 UTC 2016
      mZxid = 0x20000001e
      mtime = Tue Jun 07 12:22:58 UTC 2016
      pZxid = 0x20000001f
      cversion = 1
      dataVersion = 0
      aclVersion = 1
      ephemeralOwner = 0x0
      dataLength = 0
      numChildren = 1
      [zk: dk-test-0706-3.openstacklocal:2181(CONNECTED) 5] getAcl /hadoop-kms 
      : cdrwa
      [zk: dk-test-0706-3.openstacklocal:2181(CONNECTED) 6]