Github user dyozie commented on a diff in the pull request:
https://github.com/apache/incubator-hawq-docs/pull/132#discussion_r147239653
--- Diff: markdown/clientaccess/kerberos-userauth.html.md.erb ---
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+---
+title: Configuring Kerberos User Authentication for HAWQ
+---
+
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+
+When Kerberos authentication is enabled at the user level, HAWQ uses the
Generic Security Service Application Program Interface \(GSSAPI\) to provide
automatic authentication \(single sign-on\). When HAWQ uses Kerberos user
authentication, HAWQ itself and the HAWQ users \(roles\) that require Kerberos
authentication require a principal and keytab. When a user attempts to log in
to HAWQ, HAWQ uses its Kerberos principal to connect to the Kerberos server,
and presents the user's principal for Kerberos validation. If the user
principal is valid, login succeeds and the user can access HAWQ. Conversely,
the login fails and HAWQ denies access to the user if the principal is not
valid.
+
+When HAWQ utilizes Kerberos for user authentication, it uses a standard
principal to connect to the Kerberos KDC. The format of this principal is
`postgres/<FQDN_of_master>@<realm>`, where \<FQDN\_of\_master\> refers to the
fully qualified distinguish name of the HAWQ master node.
+
+(You may choose to configure HAWQ user principals before you enable
Kerberos user authentication for HAWQ. See [Configuring Kerberos-Authenticated
HAWQ Users](#hawq_kerb_user_cfg).)
+
+The procedure to configure Kerberos user authentication for HAWQ includes:
+
+If you use an MIT Kerberos KDC Server:
+**Step 1a**: [Configuring the HAWQ Principals using an MIT KDC
Server](#hawq_kerb_cfg_mitkdc)
+
+If you use an Active Directory Kerberos KDC Server:
+**Step 1b**: [Configuring the HAWQ Principal using an AD KDC
Server](#hawq_kerb_cfg_adkdc)
+
+**Step 2**: [Configuring HAWQ to use Kerberos
Authentication](#hawq_kerb_cfg)
+**Step 3**: [Configuring Kerberos-Authenticated HAWQ
Users](#hawq_kerb_user_cfg)
+**Step 4**: [Authenticating User Access to HAWQ](#hawq_kerb_dbaccess)
+
+## <a id="hawq_kerb_cfg_mitkdc"></a>Step 1a: Configuring the HAWQ
Principals using an MIT KDC Server
+
+Perform the following procedure to configure HAWQ Kerberos and `gpadmin`
principals when you are using an MIT KDC server.
+
+**Note**: Some operations may differ based on whether or not you have
configured secure HDFS. These operations are called out below.
+
+1. Log in to the Kerberos KDC server system:
+
+ ``` shell
+ $ ssh root@<kdc-server>
+ root@kdc-server$
+ ```
+
+2. Create a keytab entry for the HAWQ `postgres/<master>` principal using
the `kadmin.local` command. Substitute the HAWQ master node fully qualified
distinguished hostname and your Kerberos realm. For example:
+
+ ``` shell
+ root@kdc-server$ kadmin.local -q "addprinc -randkey
postgres/<master>@REALM.DOMAIN"
+ ```
+
+ The `addprinc` command adds the principal `postgres/<master>` to the
KDC managing your \<realm\>.
+
+3. Generate a keytab file for the HAWQ `postgres/<master>` principal.
Provide the same name you used to create the principal.
+
+ **If you have configured Kerberos for your HDFS filesystem**, add the
keytab to the HAWQ client HDFS keytab file:
+
+ ``` shell
+ root@kdc-server$ kadmin.local -q "xst -norandkey -k
/etc/security/keytabs/hawq.service.keytab postgres/<master>@REALM.DOMAIN"
+ ```
+
+ **Otherwise**, generate a new file for the keytab:
+
+ ``` shell
+ root@kdc-server$ kadmin.local -q "xst -norandkey -k hawq-krb5.keytab
postgres/<master>@REALM.DOMAIN"
+ ```
+
+4. Use the `klist` command to view the key you just generated:
+
+ ``` shell
+ root@kdc-server$ klist -ket ./hawq-krb5.keytab
+ ```
+
+ Or:
+
+ ``` shell
+ root@kdc-server$ klist -ket /etc/security/keytabs/hawq.service.keytab
+ ```
+
+ The `-ket` option lists the keytabs and encryption types in the
identified key file.
+
+5. When you enable Kerberos user authentication for HAWQ, you must create
a Kerberos principal for `gpadmin` or another HAWQ administrative user. Create
a Kerberos principal for the HAWQ `gpadmin` administrative role, substituting
your Kerberos realm. For example:
+
+ ``` shell
+ root@kdc-server$ kadmin.local -q "addprinc -pw changeme
gpadmin@REALM.DOMAIN"
+ ```
+
+ This `addprinc` command adds the principal `gpadmin` to the Kerberos
KDC managing your \<realm\>. When you invoke `kadmin.local` as specified in the
example above, `gpadmin` will be required to provide the password identified by
the `-pw` option when authenticating. Alternatively, you can create a keytab
file for the `gpadmin` principal and distribute the file to HAWQ client nodes.
+
+6. Copy the file in which you added the `postgres/<master>@<realm>` keytab
to the HAWQ master node:
+
+ ``` shell
+ root@kdc-server$ scp ./hawq-krb5.keytab gpadmin@<master>:/home/gpadmin/
+ ```
+
+ Or:
+
+ ``` shell
+ root@kdc-server$ scp /etc/security/keytabs/hawq.service.keytab
gpadmin@<master>:/etc/security/keytabs/hawq.service.keytab
+ ```
+
+## <a id="hawq_kerb_cfg_adkdc"></a>Step 1b: Configuring the HAWQ Principal
using an AD KDC Server
+
+Perform the following procedure to configure a HAWQ Kerberos principal
when you are using an AD KDC server.
+
+1. Log on to the Windows Active Directory Kerberos KDC server system as a
user with administrator privileges.
+
+2. From the **Start** menu, select **Control Panel > Administrative Tools
> Active Directory Users and Computers**. (If the **Active Directory Users and
Computers** menu item is not available, the Active Directory service may not
have been (correctly) installed.)
--- End diff --
remove parentheses from `(correctly)`.
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