Stages in Adding a Backend Host

The page describes the expansion of a cluster with new hosts, which is similar to the Weka System Installation Process Using the CLI and consists of the following stages.

Stage 1: Obtaining the Weka Install File

This stage is the same as Obtaining the Weka Install File. However, it is essential to download the install file used when the existing cluster was formed or last upgraded. Use the weka-status command to show the current cluster install file version.

To download the appropriate install file, follow the instructions in Download the Weka Software.

Stage 2: Installing the Weka Software on the New Host

Follow the instructions appearing in Installation of the Weka Software on Each Host. At the end of the install process, the host is in stem mode.

Stage 3: Adding a Host to the Cluster

Command: weka cluster host add

Once the backend host is in the stem mode, use the following command line on any host to add it to the cluster:

weka -H <existing-backend-hostname> cluster host add <backend-hostname>

Parameters in Command Line

Name

Type

Value

Limitations

Mandatory

Default

existing-backend-hostname

String

IP/hostname of one of the existing backend instances in the cluster

Valid hostname (DNS or IP)

No

The host on which the command is executed

backend-hostname

String

IP/hostname of the backend currently being added

Valid hostname (DNS or IP)

Yes

Note: On completion of this stage, the host-ID of the newly added host will be received. Make a note of it for the next steps.

Stage 4: Configuration of Networking

Follow the instructions appearing in Configuration of Networking.

Stage 5: Configuration of SSDs

Follow the instructions appearing in Configuration of SSDs.

Stage 6: Configuration of CPU Resources

Follow the instructions appearing in Configuration of CPU Resources.

Stage 7: Configuration of Memory

Use the following command line to display a listing of the memory defined (one line for each host):

weka cluster host

To configure the memory, follow the instructions appearing in Configuration of Memory.

Note: If the memory has been configured, it is mandatory to use the same memory for the expanded host.

Stage 8: Configuration of Failure Domains

Follow the instructions appearing in Configuration of Failure Domains.

Note: Plan whether each host is being added to an existing failure domain or to a new failure domain.

Stage 9: Applying Hosts Configuration

If hosts have been added to the cluster, follow the instructions appearing in Applying Hosts Configuration.

Note: The activation of cluster hosts can be performed with a sequence of hosts.

Import Host Settings

Instead of carrying steps 4-9 above, it is possible to import the host setting from a previously exported host in the cluster. In most cases the host configurations are similar, and importing can save some extra steps and avoid misconfiguration.

To export settings from a host, ssh to this host, and run the weka local resources export command.

To import the settings to the new host, ssh to it and run the weka local resources import command. You can then edit the local configuration as described in Local resources editing commands section and run weka local resources apply to apply the configuration.