Layering Configuration Documents

The Configuration Importer can collect together and import multiple configuration documents at the same time if instructed to import from a directory. The Configuration Importer orders the documents alphabetically, and then constructs the configuration by layering the documents one on top of the other. You can build up configuration for the same object, such as a virtual server, over multiple documents, with later documents masking settings applied by earlier documents.

The following two example configuration documents reference the same "example-service" virtual server object. The "10-base-service.yaml" file is applied first and creates the base configuration for the service. The file "20-set-rules.yaml" is alphabetically second in order of priority and layered on top of the base configuration to add a TrafficScript rule to the virtual server, and to disable web caching.

10-base-service.yaml
`version: 6.1` `virtual_servers:` `- name: example-service` `properties:` `basic:` `enabled: true` `port: 80` `protocol: http` `pool: example-pool` `web_cache:` `enabled: true` `pools:` `- name: example-pool` `properties:` `basic:` `passive_monitoring: true` `monitors: [ "Simple HTTP" ]` `nodes_table:` `- node: application-server-1:8080` `- node: application-server-2:8080`

10-base-service.yaml

version: 6.1

virtual_servers:

- name: example-service

properties:

basic:

enabled: true

port: 80

protocol: http

pool: example-pool

web_cache:

enabled: true

pools:

- name: example-pool

properties:

basic:

passive_monitoring: true

monitors: [ "Simple HTTP" ]

nodes_table:

- node: application-server-1:8080

- node: application-server-2:8080

20-set-rules.yaml
`version: 6.1` `virtual_servers:` `- name: example-service` `properties:` `basic:` `request_rules: [ set-host ]` `web_cache:` `enabled: false` `rules:` `- name: set-host` `content: \|` `http.setHeader("Host", "app1.example.com");`

20-set-rules.yaml

version: 6.1

virtual_servers:

- name: example-service

properties:

basic:

request_rules: [ set-host ]

web_cache:

enabled: false

rules:

- name: set-host

content: |

http.setHeader("Host", "app1.example.com");

Importing the two documents applies configuration equivalent to the following single document:

flattened-config.yaml
`version: 6.1` `virtual_servers:` `- name: example-service` `properties:` `basic:` `enabled: true` `port: 80` `protocol: http` `pool: example-pool` `request_rules: [ set-host ]` `web_cache:` `enabled: false` `pools:` `- name: example-pool` `properties:` `basic:` `passive_monitoring: true` `monitors: [ "Simple HTTP" ]` `nodes_table:` `- node: application-server-1:8080` `- node: application-server-2:8080` `rules:` `- name: set-host` `content: \|` `http.setHeader("Host", "app1.example.com");`

flattened-config.yaml

version: 6.1

virtual_servers:

- name: example-service

properties:

basic:

enabled: true

port: 80

protocol: http

pool: example-pool

request_rules: [ set-host ]

web_cache:

enabled: false

pools:

- name: example-pool

properties:

basic:

passive_monitoring: true

monitors: [ "Simple HTTP" ]

nodes_table:

- node: application-server-1:8080

- node: application-server-2:8080

rules:

- name: set-host

content: |

http.setHeader("Host", "app1.example.com");

Observe that both files specify the "virtual_servers.properties.web_cache.enabled" setting, although the Configuration Importer applies the "false" value in "20-set-rules.yaml" last, so this is the resultant setting applied to the Traffic Manager.

Ivanti recommends limiting overlaying of specific settings within an object to basic scalar values. Layering semantics for non-scalar settings, such as lists or tables, is presently unspecified.