druid/docs/content/development/extensions-core/druid-kerberos.md

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Druid-Kerberos

Druid Extension to enable Authentication for Druid Nodes using Kerberos. This extension adds an Authenticator which is used to protect HTTP Endpoints using the simple and protected GSSAPI negotiation mechanism SPNEGO. Make sure to include druid-kerberos as an extension.

Configuration

Creating an Authenticator

druid.auth.authenticatorChain=["MyKerberosAuthenticator"]

druid.auth.authenticator.MyKerberosAuthenticator.type=kerberos

To use the Kerberos authenticator, add an authenticator with type kerberos to the authenticatorChain. The example above uses the name "MyKerberosAuthenticator" for the Authenticator.

Configuration of the named authenticator is assigned through properties with the form:

druid.auth.authenticator.<authenticatorName>.<authenticatorProperty>

The configuration examples in the rest of this document will use "kerberos" as the name of the authenticator being configured.

Properties

Property Possible Values Description Default required
druid.auth.authenticator.kerberos.internalClientPrincipal druid@EXAMPLE.COM Principal user name, used for internal node communication empty Yes
druid.auth.authenticator.kerberos.internalClientKeytab /etc/security/keytabs/druid.keytab Path to keytab file used for internal node communication empty Yes
druid.auth.authenticator.kerberos.serverPrincipal HTTP/_HOST@EXAMPLE.COM SPNego service principal used by druid nodes empty Yes
druid.auth.authenticator.kerberos.serverKeytab /etc/security/keytabs/spnego.service.keytab SPNego service keytab used by druid nodes empty Yes
druid.auth.authenticator.kerberos.authToLocal RULE:[1:$1@$0](druid@EXAMPLE.COM)s/.*/druid DEFAULT It allows you to set a general rule for mapping principal names to local user names. It will be used if there is not an explicit mapping for the principal name that is being translated. DEFAULT No
druid.auth.authenticator.kerberos.excludedPaths ['/status','/health'] Array of HTTP paths which which does NOT need to be authenticated. None No
druid.auth.authenticator.kerberos.cookieSignatureSecret secretString Secret used to sign authentication cookies. It is advisable to explicitly set it, if you have multiple druid ndoes running on same machine with different ports as the Cookie Specification does not guarantee isolation by port. No
druid.auth.authenticator.kerberos.authorizerName Depends on available authorizers Authorizer that requests should be directed to Empty Yes

As a note, it is required that the SPNego principal in use by the druid nodes must start with HTTP (This specified by RFC-4559) and must be of the form "HTTP/_HOST@REALM". The special string _HOST will be replaced automatically with the value of config druid.host

Auth to Local Syntax

druid.auth.authenticator.kerberos.authToLocal allows you to set a general rules for mapping principal names to local user names. The syntax for mapping rules is RULE:\[n:string](regexp)s/pattern/replacement/g. The integer n indicates how many components the target principal should have. If this matches, then a string will be formed from string, substituting the realm of the principal for $0 and the nth component of the principal for $n. e.g. if the principal was druid/admin then \[2:$2$1suffix] would result in the string admindruidsuffix. If this string matches regexp, then the s//[g] substitution command will be run over the string. The optional g will cause the substitution to be global over the string, instead of replacing only the first match in the string. If required, multiple rules can be be joined by newline character and specified as a String.

Increasing HTTP Header size for large SPNEGO negotiate header

In Active Directory environment, SPNEGO token in the Authorization header includes PAC (Privilege Access Certificate) information, which includes all security groups for the user. In some cases when the user belongs to many security groups the header to grow beyond what druid can handle by default. In such cases, max request header size that druid can handle can be increased by setting druid.server.http.maxRequestHeaderSize (default 8Kb) and druid.router.http.maxRequestBufferSize (default 8Kb).

Accessing Druid HTTP end points when kerberos security is enabled

  1. To access druid HTTP endpoints via curl user will need to first login using kinit command as follows -

    kinit -k -t <path_to_keytab_file> user@REALM.COM
    
  2. Once the login is successful verify that login is successful using klist command

  3. Now you can access druid HTTP endpoints using curl command as follows -

    curl --negotiate -u:anyUser -b ~/cookies.txt -c ~/cookies.txt -X POST -H'Content-Type: application/json' <HTTP_END_POINT>
    

    e.g to send a query from file query.json to druid broker use this command -

    curl --negotiate -u:anyUser -b ~/cookies.txt -c ~/cookies.txt -X POST -H'Content-Type: application/json'  http://broker-host:port/druid/v2/?pretty -d @query.json
    

    Note: Above command will authenticate the user first time using SPNego negotiate mechanism and store the authentication cookie in file. For subsequent requests the cookie will be used for authentication.

Accessing coordinator or overlord console from web browser

To access Coordinator/Overlord console from browser you will need to configure your browser for SPNego authentication as follows -

  1. Safari - No configurations required.
  2. Firefox - Open firefox and follow these steps -
    1. Go to about:config and search for network.negotiate-auth.trusted-uris.
    2. Double-click and add the following values: "http://druid-coordinator-hostname:ui-port" and "http://druid-overlord-hostname:port"
  3. Google Chrome - From the command line run following commands -
    1. google-chrome --auth-server-whitelist="druid-coordinator-hostname" --auth-negotiate-delegate-whitelist="druid-coordinator-hostname"
    2. google-chrome --auth-server-whitelist="druid-overlord-hostname" --auth-negotiate-delegate-whitelist="druid-overlord-hostname"
  4. Internet Explorer -
    1. Configure trusted websites to include "druid-coordinator-hostname" and "druid-overlord-hostname"
    2. Allow negotiation for the UI website.

Sending Queries programmatically

Many HTTP client libraries, such as Apache Commons HttpComponents, already have support for performing SPNEGO authentication. You can use any of the available HTTP client library to communicate with druid cluster.