Ce contenu n'est pas disponible dans la langue sélectionnée.
Chapter 7. Replacing a non-primary host using new bricks
7.1. 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.
# pkill glusterfsd # umount /gluster_bricks/{engine,vmstore,data}Check which operating system is running on your hyperconverged hosts by running the following command:
$ nodectl info
- Install the same operating system on a replacement host.
7.2. 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
NonResponsivein the Administrator Portal. Virtual machines that previously ran on this host are in theUnknownstate.-
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.
# sed -i `/failed-host-frontend.example.com/d` /root/.ssh/known_hosts # sed -i `/failed-host-backend.example.com/d` /root/.ssh/known_hosts
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
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
Use
ssh-copy-idto 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
7.3. 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 infoto 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
Back up the
node_prep_inventory.ymlfile.# cd /etc/ansible/roles/gluster.ansible/playbooks/hc-ansible-deployment # cp node_prep_inventory.yml node_prep_inventory.yml.bk
Edit the
node_prep_inventory.ymlfile to define your node preparation.See Appendix B, Understanding the
node_prep_inventory.ymlfile for more information about this inventory file and its parameters.
7.4. 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.ymlfile.# cd /etc/ansible/roles/gluster.ansible/playbooks/hc-ansible-deployment # cp node_replace_inventory.yml node_replace_inventory.yml.bk
Edit the
node_replace_inventory.ymlfile to define your cluster.See Appendix C, Understanding the
node_replace_inventory.ymlfile for more information about this inventory file and its parameters.
7.5. 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.
# 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
7.6. Removing a failed host from the cluster
When a replacement host is ready, remove the existing failed host from the cluster.
Procedure
Remove the failed host.
- Log in to the Administrator Portal.
Click Compute
Hosts. The replacement host is in the
NonResponsivestate. Virtual machines running on that host are in theUnknownstate.- Select the replacement host.
- Click the main Action menu (⋮) for the Hosts page and select Confirm host has been rebooted.
- Click OK to confirm.
- Click the Action menu (⋮) beside the failed host and click Remove.
Clean stale Hosted Engine metadata.
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
Remove the metadata associated with that host identifier.
# hosted-engine --clean-metadata --host-id=1 --force
7.7. 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:
# for vol in `gluster volume list`; do gluster volume heal $vol info summary; done
The output shows a summary of healing activity on each brick in each volume, for example:
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
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.
