Workflow: Add a backend host

Expanding a cluster with a new backend host is similar to the Weka system installation process using the CLI.

Note: In most cases, the host configurations are similar. Therefore, it is possible to import the host setting from a previously exported host in the cluster, saving time and avoiding misconfiguration. See Expand the Cluster by Importing the Host Settings.

Add a backend host to an existing cluster

Stage 1: Obtain the Weka install file

Download the Weka Install File used when the existing cluster was last upgraded (or formed, if not upgraded)..

Use the weka status command to show the current cluster install file version.

See Obtain the Weka software installation package

Stage 2: Install the Weka software on the new host

Run the untar command and install.sh command on the new host. At the end of the installation process, the host is in stem mode (the host is not attached to a cluster).

Stage 3: Add the host to the cluster

Command: weka cluster host add

On any host that is part of the cluster, run the following command line:

weka cluster host add <backend-hostname>

Parameters:

Name	Type	Value	Limitations	Mandatory	Default
backend-hostname	String	IP/hostname of the new backend host to add	Valid hostname (DNS or IP)	Yes

Note: On completion of this stage, the host-ID of the newly added host appears in response to the command. Make a note of it to use in the following steps.

Stage 4: Configure the networking

Perform the instructions in #stage-6-configure-the-networking.

Stage 5: Configure the CPU resources

Perform the instructions in #stage-8-configure-the-cpu-resources.

Stage 6: Apply the host's configuration

Apply the configuration on the newly added host. Perform the instructions in #stage-13-apply-hosts-configuration.

Note: You can activate the cluster hosts sequentially.

Stage 7: Configure the SSDs

Perform the instructions in #stage-7-configure-the-ssds.

Expand the cluster by importing the host settings

In most cases, the host configurations are similar. Therefore, it is possible to import the host setting from a previously exported host in the cluster, saving time and avoiding misconfiguration.

Procedure:

1. Perform only stages 1 to 3 in the Add a backend host to an existing cluster procedure (above).
2. Connect to one of the hosts in the cluster and export the settings by running the following command: weka local resources export.

3. Connect to the new host and import the settings by running the following command: weka local resources import.

4. Edit the local configuration. See the Local resources editing commands section.
5. Apply the configuration on the newly added host. See #stage-13-apply-hosts-configuration.