Chapter 5. Creating new bricks and configuration 5.1. Host replacement prerequisites Determine which node to use as the Ansible controller node (the node from which all Ansible playbooks are executed). Red Hat recommends using a healthy node in the same cluster as the failed node as the Ansible controller node. Stop brick processes and unmount file systems on the failed host, to avoid file system inconsistency issues. Check which operating system is running on your hyperconverged hosts by running the following command: Reinstall the same operating system on the failed hyperconverged host. 5.2. Preparing the cluster for host replacement Verify host state in the Administrator Portal. Log in to the Red Hat Virtualization Administrator Portal. The host is listed as NonResponsive in the Administrator Portal. Virtual machines that previously ran on this host are in the Unknown state. Click Compute Hosts and click the Action menu (...). Click Confirm host has been rebooted and confirm the operation. Verify that the virtual machines are now listed with a state of Down . Update the SSH fingerprint for the failed node. Log in to the Ansible controller node as the root user. Remove the existing SSH fingerprint for the failed node. Copy the public key from the Ansible controller node to the freshly installed node. Verify that you can log in to all hosts in the cluster, including the Ansible controller node, using key-based SSH authentication without a password. Test access using all network addresses. The following example assumes that the Ansible controller node is host1 . Use ssh-copy-id to copy the public key to any host you cannot log into without a password using this method. 5.3. Creating the node_prep_inventory.yml file Define the replacement node in the node_prep_inventory.yml file. Procedure Familiarize yourself with your Gluster configuration. The configuration that you define in your inventory file must match the existing Gluster volume configuration. Use gluster volume info to check where your bricks should be mounted for each Gluster volume, for example: Back up the node_prep_inventory.yml file. Edit the node_prep_inventory.yml file to define your node preparation. See Appendix B, Understanding the node_prep_inventory.yml file for more information about this inventory file and its parameters. 5.4. Creating the node_replace_inventory.yml file Define your cluster hosts by creating a node_replacement_inventory.yml file. Procedure Back up the node_replace_inventory.yml file. Edit the node_replace_inventory.yml file to define your cluster. See Appendix C, Understanding the node_replace_inventory.yml file for more information about this inventory file and its parameters. 5.5. Executing the replace_node.yml playbook file The replace_node.yml playbook reconfigures a Red Hat Hyperconverged Infrastructure for Virtualization cluster to use a new node after an existing cluster node has failed. Procedure Execute the playbook. 5.6. Finalizing host replacement After you have replaced a failed host with a new host, follow these steps to ensure that the cluster is connected to the new host and properly activated. Procedure Activate the host. Log in to the Red Hat Virtualization Administrator Portal. Click Compute Hosts and observe that the replacement host is listed with a state of Maintenance . Select the host and click Management Activate . Wait for the host to reach the Up state. Attach the gluster network to the host. Click Compute Hosts and select the host. Click Network Interfaces Setup Host Networks . Drag and drop the newly created network to the correct interface. Ensure that the Verify connectivity between Host and Engine checkbox is checked. Ensure that the Save network configuration checkbox is checked. Click OK to save. Verify the health of the network. Click the Network Interfaces tab and check the state of the host's network. If the network interface enters an "Out of sync" state or does not have an IP Address, click Management Refresh Capabilities . 5.7. Verifying healing in progress After replacing a failed host with a new host, verify that your storage is healing as expected. Procedure Verify that healing is in progress. Run the following command on any hyperconverged host: The output shows a summary of healing activity on each brick in each volume, for example: Depending on brick size, volumes can take a long time to heal. You can still run and migrate virtual machines using this node while the underlying storage heals.

Commands:
pkill glusterfsd umount /gluster_bricks/{engine,vmstore,data}
nodectl info
sed -i `/ failed-host-frontend.example.com /d` /root/.ssh/known_hosts sed -i `/ failed-host-backend.example.com /d` /root/.ssh/known_hosts
ssh-copy-id root@ new-host-backend.example.com ssh-copy-id root@ new-host-frontend.example.com
ssh root@ host1-backend.example.com ssh root@ host1-frontend.example.com ssh root@ host2-backend.example.com ssh root@ host2-frontend.example.com ssh root@ new-host-backend.example.com ssh root@ new-host-frontend.example.com
ssh-copy-id root@ host-frontend.example.com ssh-copy-id root@ host-backend.example.com
gluster volume info engine | grep -i brick Number of Bricks: 1 x 3 = 3 Bricks: Brick1: host1.example.com:/gluster_bricks/engine/engine Brick2: host2.example.com:/gluster_bricks/engine/engine Brick3: host3.example.com:/gluster_bricks/engine/engine
cd /etc/ansible/roles/gluster.ansible/playbooks/hc-ansible-deployment cp node_prep_inventory.yml node_prep_inventory.yml.bk
cd /etc/ansible/roles/gluster.ansible/playbooks/hc-ansible-deployment cp node_replace_inventory.yml node_replace_inventory.yml.bk
cd /etc/ansible/roles/gluster.ansible/playbooks/hc-ansible-deployment/ ansible-playbook -i node_prep_inventory.yml -i node_replace_inventory.yml tasks/replace_node.yml
for vol in `gluster volume list`; do gluster volume heal USDvol info summary; done
Brick brick1 Status: Connected Total Number of entries: 3 Number of entries in heal pending: 2 Number of entries in split-brain: 1 Number of entries possibly healing: 0