Chapter 7. Replacing a non-primary host using new bricks

1. Verify host state in the Administrator Portal.

   1. 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.

   2. Click Compute Hosts and click the Action menu (⋮).
   3. Click Confirm host has been rebooted and confirm the operation.
   4. Verify that the virtual machines are now listed with a state of Down.

2. Update the SSH fingerprint for the failed node.

   1. Log in to the Ansible controller node as the root user.

   2. Remove the existing SSH fingerprint for the failed node.

      # sed -i `/failed-host-frontend.example.com/d` /root/.ssh/known_hosts
      # sed -i `/failed-host-backend.example.com/d` /root/.ssh/known_hosts

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   3. Copy the public key from the Ansible controller node to the freshly installed node.

      # ssh-copy-id root@new-host-backend.example.com
      # ssh-copy-id root@new-host-frontend.example.com

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   4. 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.

      # 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

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      Use ssh-copy-id to copy the public key to any host you cannot log into without a password using this method.

      # ssh-copy-id root@host-frontend.example.com
      # ssh-copy-id root@host-backend.example.com

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Procedure

1. 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:

   # 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

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2. Back up the node_prep_inventory.yml file.

   # cd /etc/ansible/roles/gluster.ansible/playbooks/hc-ansible-deployment
   # cp node_prep_inventory.yml node_prep_inventory.yml.bk

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3. 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.

Procedure

1. Back up the node_replace_inventory.yml file.

   # cd /etc/ansible/roles/gluster.ansible/playbooks/hc-ansible-deployment
   # cp node_replace_inventory.yml node_replace_inventory.yml.bk

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2. 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.

Procedure

1. Execute the playbook.

   # 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

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Procedure

1. Remove the failed host.

   1. Log in to the Administrator Portal.

   2. Click Compute Hosts.

      The replacement host is in the NonResponsive state. Virtual machines running on that host are in the Unknown state.

   3. Select the replacement host.
   4. Click the main Action menu (⋮) for the Hosts page and select Confirm host has been rebooted.
   5. Click OK to confirm.
   6. Click the Action menu (⋮) beside the failed host and click Remove.

2. Clean stale Hosted Engine metadata.

   1. Determine the identifier of the failed node.

      # hosted-engine --vm-status | grep failed-node.example.com
      --== Host server1-frontend.example.com (id: 1) status ==--
      Hostname                           : failed-node.example.com

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   2. Remove the metadata associated with that host identifier.

      # hosted-engine --clean-metadata --host-id=1 --force

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