hbase_relay

Synopsis

Issuing some commands to specifics subsystem, such as HBase require a quite complex client configuration.

To avoid this, HADeploy will not issue such command directly, but push the command on one of the cluster node, called ’Relay node'. An edge node of the cluster would typically assume this function.

hbase_relay will define which host will be used to relay operations for HBase, and also how these operations will be performed.

There should be only one entry of this type in the HADeploy definition file.

Attributes

hbase_relay is a map with the following attributes:

Name	req?	Description
host	yes	The host on which all hbase commands will be pushed for execution. Must be fully configured as HBase client.
tools_folder	no	Folder used by HADeploy to install some tools for HBase management. Default: /tmp/hadeploy_<user>/ where user is the ssh_user defined for this relay host.
principal	no	A Kerberos principal allowing all HBase related operation to be performed. See below
local_keytab_path	no	A local path to the associated keytab file. This path is relative to the embeding file. See below
relay_keytab_path	no	A path to the associated keytab file on the relay host. See below
become_user	no	A user account under which all namespace and table operations will be performed. Only used on non-Kerberos cluster. Note: The ssh_user defined for this relay host must have enough rights to switch to this become_user using the become_method below. Default: No user switch, so the ssh_user defined for this relay host will be used.
become_method	no	The method used to swith to this user. Refer to the Ansible documentation on this parameter. Default: Ansible default (sudo).
when	no	Boolean. Allow conditional deployment of this item. Default True

Kerberos authentication

When principal and ..._keytab_path variables are defined, Kerberos authentication will be activated for all HBase operations.

• All HBase operations will be performed on behalf of the user defined by the provided principal.

• This principal must have enough rights to be able to create namespaces and HBase table.

Regarding the keytab file, two cases:

• This keytab file already exists on the relay host. In such case, the relay_keytab_path must be set to the location of this file. And the relay host's ssh_user must have read access on it.
  Normally, for HBase, there should be at least one principal and keytab file created with full privileges by the system during Kerberos setup.

• This keytab file is not present on the relay host. In such case the local_keytab_path must be set to its local location. HADeploy will take care of copying it on the remote relay host, in a location under tools_folder. Note you can also modify this target location by setting also the relay_keytab_path parameter. In this case, it must be the full path, including the keytab file name. And the containing folder must exists.

Example

hbase_relay:
  host: en1

With Kerberos activated:

hbase_relay:
  host: en1
  principal: hbase-mycluster
  relay_keytab_path: /etc/security/keytabs/hbase.headless.keytab