Workflow: Add 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: Obtain the Weka software installation 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: Install 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 installation process, the host is in stem mode.

Stage 3: Add the 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>
IP/hostname of one of the existing backend instances in the cluster
Valid hostname (DNS or IP)
The host on which the command is executed
IP/hostname of the backend currently being added
Valid hostname (DNS or IP)
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: Configure the networking

See Configure the networking in Weka system installation process using the CLI.

Stage 5: Configure the SSDs

Stage 6: Configure the CPU resources

See Configure the CPU resources in Weka system installation process using the CLI.

Stage 7: Configure the memory

To display a list of the memory defined (one line per host), run the following command:
weka cluster host
To configure the memory, see Configure the memory inWeka system installation process using the CLI.
Note: If the memory is configured, you must use the same memory for the expanded host.

Stage 8: Configure failure domains

See Configure failure domains in Weka system installation process using the CLI.
Note: Plan whether each host is added to an existing failure domain or to a new failure domain.

Stage 9: Apply hosts configuration

If hosts are already added to the cluster, see Apply hosts configuration in Weka system installation process using the CLI.
Note: The activation of cluster hosts can be performed with a sequence of hosts.

Import host settings

Instead of carrying stages 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.