Node filters

A node filter is a search expression used to identify a set of nodes using SQL-like expressions on any namespace and attribute. You can create node filters that include or exclude nodes based on specific pattern sets.

When the filter is evaluated, Chef Courier creates a node list from the set of registered nodes at the time that the filter is evaluated.

Create a node filter

1. Create a node filter payload in a JSON file:

   {
       "name": "<FILTER_NAME>",
       "constraints": {
           "attributes": [{
               "name": "<ATTRIBUTE_NAME>",
               "operator": "<OPERATOR>",
               "value": ["<ATTRIBUTE_VALUE>"],
               "namespace": ["<NAMESPACE_NAME>"]
           }]
       }
   }
   

   Replace:

   • <FILTER_NAME> with a name for the filter

   • <ATTRIBUTE_NAME> with an attribute to filter by

   • <OPERATOR> with an filter operator. The supported operators are:

     • MATCHES
     • CONTAINS
     • =
     • !=

   • <ATTRIBUTE_VALUE> with the attribute value filter operator matches against

   • <NAMESPACE_NAME> with the namespace to search in. The following namespaces are supported:

     • agent for node attributes collected from the Node Management Agent
     • gohai for node attributes collected by the Gohai skill
     • aws for AWS-specific attributes collected by the Gohai skill
     • azure for Azure-specific attributes collected by the Gohai skill
     • tags for tags applied to nodes using Node Management

2. Create and save a node filter:

   chef-node-management-cli management filter create-filter --body-file <FILTER_FILENAME>
   

   The response is similar to the following:

   {
       "item": {
       "filterId": "ab38aed7-f35a-4e44-90f5-ef9ea11e6464"
       }
   }
   

Get nodes from a filter

To get nodes from an adhoc filter, use the filter run-adhocFilter subcommand:

chef-node-management-cli management filter run-adhocFilter --body-file <FILTER_FILENAME>

To get nodes from a saved filter, use the filter run-savedFilter subcommand:

chef-node-management-cli management filter run-savedFilter --filterId <FILTER_ID>