Adding or Deleting sFlow Collector Nodes by Modifying instances.yml

This topic describes adding or deleting flow collector nodes to an existing Contrail cluster by modifying the instances.yml file, which gets generated when Contrail cluster is provisioned by using Contrail Command UI. The instances.yml file is created inside /var/tmp/contrail_cluster/<contrail_cluster_id> in contrail_command container.

You can:

• Add flow collector nodes to a Contrail cluster without any existing flow collector node.

• Add flow collector nodes to a Contrail cluster with existing flow collector nodes.

• Delete flow collector nodes from a Contrail cluster.

When a new flow collector node is added, or an existing flow collector node is deleted by modifying the existing instances.yml file:

1. Ansible playbook will run to first cleanup the flow collector nodes which need to be deleted.

2. Then Ansible playbook will run to set up the new flow collector nodes and to rebuild the cluster.

To add flow collector nodes:

1. Modify the instances.yml file to add flow-collector nodes.

   Existing cluster details are in the instances.yml. The appformix_flows role designates Contrail Insights Flows node. The following example shows a snippet of section for instances.yml for existing Contrail Insights Flows node details:

   New snippet for instances.yml to register one more node, host2, in the Contrail Insights Flows cluster:

2. Run the following commands to add flow collector nodes:

To delete nodes from the Contrail cluster:

1. Modify the instances.yml file to delete flow collector nodes. The following example shows a snippet of section for instances.yml for existing Contrail Insights Flows node details:

   New snippet for instances.yml to deregister host2 from the Contrail Insights Flows cluster by detaching the appformix_flows role from host2:

2. Run the following commands to delete the flow collector nodes: