Red Hat OpenShift Container Platform 3.10 with Container-Native Storage 3.9

This post documents how to install Container-Native Storage 3.9 (CNS 3.9) with OpenShift Container Platform 3.10 (OCP 3.10). CNS provides persistent storage for OCP's general-application consumption and for the registry.

CNS 3.9 installation with OCP 3.10 advanced installer

The deployment of CNS 3.9 can be accomplished using openshift-ansible playbooks and specific inventory file options. The first group of hosts in glusterfs specifies a cluster for general-purpose application storage and will, by default, come with the StorageClass glusterfs-storage to enable dynamic provisioning. For high availability of storage, it's very important to have four nodes for the general-purpose application cluster, glusterfs. The second group, glusterfs_registry, specifies a cluster that will host a single, statically deployed PersistentVolume for use exclusively by a hosted registry that can scale. This cluster will not offer a StorageClass for file-based PersistentVolumes with the options and values as they are currently configured.

Following is an example of a partial inventory file with selected options concerning deployment of CNS 3.9 for applications and registry. When using options for deployment with values of specific sizes, (e.g., openshift_hosted_registry_storage_volume_size=10Gi) or node selectors, (e.g., node-role.kubernetes.io/infra=true) they should be adjusted for your particular deployment needs.

[OSEv3:children]
...
nodes
glusterfs
glusterfs_registry

[OSEv3:vars]
...      
# registry
openshift_hosted_registry_storage_kind=glusterfs       
openshift_hosted_registry_storage_volume_size=10Gi   
openshift_hosted_registry_selector="node-role.kubernetes.io/infra=true"

# Container image to use for glusterfs pods
openshift_storage_glusterfs_image="registry.access.redhat.com/rhgs3/rhgs-server-rhel7
:v3.9"
# Container image to use for gluster-block-provisioner pod
openshift_storage_glusterfs_block_image="registry.access.redhat.com/rhgs3/rhgs-gluster-
block-prov-rhel7:v3.9"
# Container image to use for heketi pods
openshift_storage_glusterfs_heketi_image="registry.access.redhat.com/rhgs3/rhgs-
volmanager-rhel7:v3.9"
 
# CNS storage cluster for applications
openshift_storage_glusterfs_namespace=app-storage
openshift_storage_glusterfs_storageclass=true
openshift_storage_glusterfs_storageclass_default=false
openshift_storage_glusterfs_block_deploy=false

# CNS storage cluster for OpenShift infrastructure
openshift_storage_glusterfs_registry_namespace=infra-storage  
openshift_storage_glusterfs_registry_storageclass=false       
openshift_storage_glusterfs_registry_block_deploy=false   
openshift_storage_glusterfs_registry_block_host_vol_create=false    
openshift_storage_glusterfs_registry_block_host_vol_size=100  
openshift_storage_glusterfs_registry_block_storageclass=false
openshift_storage_glusterfs_registry_block_storageclass_default=false   

...
[nodes]
…
ose-app-node01.ocpgluster.com openshift_node_group_name="node-config-compute"
ose-app-node02.ocpgluster.com openshift_node_group_name="node-config-compute"
ose-app-node03.ocpgluster.com openshift_node_group_name="node-config-compute"
ose-app-node04.ocpgluster.com openshift_node_group_name="node-config-compute"
ose-infra-node01.ocpgluster.com openshift_node_group_name="node-config-compute"
ose-infra-node02.ocpgluster.com openshift_node_group_name="node-config-compute"
ose-infra-node03.ocpgluster.com openshift_node_group_name="node-config-compute"

[glusterfs]
ose-app-node01.ocpgluster.com glusterfs_zone=1 glusterfs_devices='[ "/dev/xvdf" ]'   
ose-app-node02.ocpgluster.com glusterfs_zone=2 glusterfs_devices='[ "/dev/xvdf" ]'
ose-app-node03.ocpgluster.com glusterfs_zone=3 glusterfs_devices='[ "/dev/xvdf" ]'
ose-app-node04.ocpgluster.com glusterfs_zone=1 glusterfs_devices='[ "/dev/xvdf" ]'

[glusterfs_registry]
ose-infra-node01.ocpgluster.com glusterfs_zone=1 glusterfs_devices='[ "/dev/xvdf" ]'
ose-infra-node02.ocpgluster.com glusterfs_zone=2 glusterfs_devices='[ "/dev/xvdf" ]'
ose-infra-node03.ocpgluster.com glusterfs_zone=3 glusterfs_devices='[ "/dev/xvdf" ]'

CNS 3.9 uninstall

With this release, the uninstall.yml playbook can be used to remove all gluster and heketi resources. This might come in handy when there are errors in inventory file options that cause the gluster cluster to deploy incorrectly.

If you're removing a CNS installation that is currently being used by any applications, you should remove those applications before removing CNS, because they will lose access to storage. This includes infrastructure applications like registry.

If you have the registry using a glusterfs PersistentVolume, remove it with the following command:

oc delete deploymentconfig docker-registry
oc delete pvc registry-claim
oc delete pv registry-volume
oc delete service glusterfs-registry-endpoints

If running the uninstall.yml because a deployment failed, run the uninstall.yml playbook with the following variables to wipe the storage devices for both glusterfs and glusterfs_registry clusters before trying the CNS installation again:

ansible-playbook -i <path_to_inventory file> -e
"openshift_storage_glusterfs_wipe=True" -e 
"openshift_storage_glusterfs_registry_wipe=true" 
/usr/share/ansible/openshift-ansible/playbooks/openshift-glusterfs/uninstall.yml

CNS 3.9 post installation for applications and registry

You can add CNS clusters and resources to an existing OCP install using the following command. This same process can be used if CNS has been uninstalled due to errors.

ansible-playbook -i <path_to_inventory_file> 
/usr/share/ansible/openshift-ansible/playbooks/openshift-glusterfs/config.yml

After the new cluster(s) is created and validated, you can deploy the registry using a newly created glusterfs ReadWriteMany volume. Run this playbook to create the registry resources:

ansible-playbook -i <path_to_inventory_file> 
/usr/share/ansible/openshift-ansible/playbooks/openshift-hosted/config.yml

Want to learn more?

For hands-on experience combining OpenShift and CNS, check out our test drive, a free, in-browser lab experience that walks you through using both. Also watch this short video explaining why use CNS with OpenShift.