# Expansion of specific resources ## Dynamic modifications Most modifications to host configurations can be performed dynamically, without deactivating the host. Such configurations include the addition/removal of memory and network resources, changing IPs, extending network subnets and limiting the Weka system bandwidth on the host. All these changes can be performed using the relevant `weka cluster host`command. Once this command is used with a specific `host-id`selected, it will be staged for update on the cluster. To view the un-applied configuration, use the `weka cluster host resources `command. To apply the changes, use the `weka cluster host apply ` command. You can also apply these changes locally using the `weka local resources apply` command. The last local configuration (of a host that successfully joined a cluster) is saved. If a failure/problem occurs with the new configuration, the host will automatically revert to the last known good configuration. To view this configuration, use the`weka cluster host resources --stable` command. ### Memory modifications To dynamically change the memory configuration, use the steps described for the [Configuration of Memory](/4.0/install/bare-metal/using-cli.md#stage-10-configuration-of-memory-optional) on an active host, followed by the `weka cluster host apply` command. {% hint style="success" %} **Example:** To change `host-id 0` memory to 1.5 GB, run the following commands: `weka cluster host memory 0 1.5GB`\ `weka cluster host apply 0` {% endhint %} #### Release hugepages on each container After reducing the memory allocation for a container, it is required to release the hugepages on each container. Perform the following steps for each container: 1. Obtain the `release_hugepages.sh` script below and copy it to the `/opt/weka/` folder. 2. Change the script mode: Run `chmod a+x release_hugepages.sh` 3. Stop the container locally: Run `weka local stop` 4. Release hugepages: Run `weka local run /opt/weka/release_hugepages.sh` 5. Restart the container locally: Run `weka local start` {% file src="/files/dHhzFz9KBJV153sWDABW" %} ### Network modifications To dynamically change the network configuration, use the steps described for the [Configuration of Networking](/4.0/install/bare-metal/using-cli.md#stage-6-configuration-of-networking) on an active host, followed by the`weka cluster host apply` command. {% hint style="success" %} **For Example:** To add another network device to `host-id 0`, run the following commands: `weka cluster host net add 0 eth2`\ `weka cluster host apply 0` {% endhint %} {% hint style="info" %} **Note:** It is possible to accumulate several changes on a host and apply only once on completion. {% endhint %} ### Host IPs modifications To dynamically change the host's management IPs, you can use the `management-ips` resource editing command. {% hint style="success" %} **For Example:** To change the management IPs on`host-id 0`, run the following commands: `weka cluster host management-ips 192.168.1.10 192.168.1.20`\ `weka cluster host apply 0` {% endhint %} {% hint style="info" %} **Note:** The number of management IPs determines whether the host will use Highly Available Networking mode (HA), causing each IO process to use both hosts NICs. A host with 2 IPs will use HA mode and a host with only 1 IP will not use HA mode. It is also possible to define up to 4 IPs, in case the cluster is using both Infiniband and Ethernet network technologies. {% endhint %} ### Local resources editing commands It is also possible to run modification commands locally on the host by connecting to the desired host and running a `local resources` command equivalent to its `weka cluster host` counterpart. These local commands have the same semantics of their remote counterparts only that they don't receive the host-id as the first parameter and operate instead on the local host. Commands that can be performed dynamically on an Active host: `weka local resources [--stable]`\ `weka local resources apply`\ `weka local resources net`\ `weka local resources net add`\ `weka local resources net remove`\ `weka local resources memory`\ `weka local resources bandwidth`\ `weka local resources management-ips`\ `weka local resources dedicate` The following commands cannot be performed on an Active host and require deactivating the host first using `weka cluster host deactivate`: `weka local resources failure-domain`\ `weka local resources cores` ## Addition of CPU cores The addition of CPU cores to the cluster is not performed dynamically but on an inactive host. It requires the execution of the steps described in [Configuration of CPU Resources](/4.0/install/bare-metal/using-cli.md#stage-9-configuration-of-cpu-resources). For more information, contact the WekaIO Support Team. ## Expansion of only SSDs Follow the instructions appearing in [Configuration of SSDs](/4.0/install/bare-metal/using-cli.md#stage-6-configuration-of-ssds). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.weka.io/4.0/usage/expanding-and-shrinking-cluster-resources/expansion-of-specific-resources.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. 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