I85PREP
⌘ K
Cisco DCAUTO 300-635 study materials
Cisco DCAUTO 300-635 study resources

Cisco DCAUTO 300-635: Cisco ACI and NX-OS Automation with APIs and Scripting

Cisco DCAUTO 300-635 · Work through your exam, one topic at a time.

All guide sections

Cisco ACI and NX-OS Automation with APIs and Scripting

Cisco ACI and NX-OS Automation with APIs and Scripting is the largest domain: the ACI object model and APIC REST API, plus NX-OS surfaces such as NX-API, the Python SDK, on-box scripting and model-driven interfaces.

ACI: model first, then API

ACI is built on the Management Information Tree. Every object is an MO of a class (fvTenant, fvBD, fvAEPg, vzBrCP), has a distinguished name (uni/tn-Prod/ap-App/epg-Web), and can carry relations such as fvRsCons. Configuration is a POST of JSON to /api/mo/<dn>.json or /api/class/<class>.json; queries are GETs with filters like ?query-target-filter=eq(fvTenant.name,'Prod') and ?rsp-subtree=children&rsp-subtree-class=fvBD.

Authentication: POST /api/aaaLogin.json with an aaaUser object containing name and password, then send the returned token as the APIC-Cookie cookie. Tokens expire; renew with /api/aaaRefresh.json. The Cobra SDK wraps this with LoginSession and ConfigRequest.

NX-OS automation surfaces

  • NX-API (enable with feature nxapi) exposes JSON-RPC at https://<switch>/ins; the body carries ins_api with type (cli_show, cli_conf, bash), input and output_format. Multiple config lines are separated by ;.
  • The NX-OS Python SDK wraps NX-API for scripts; Guestshell runs Python on the device itself.
  • NETCONF/YANG and gNMI telemetry provide model-driven access; EEM triggers actions on device events.

Worked example

Create a tenant, bridge domain and EPG in one request.

Reasoning: build imdata as a single nested body - an fvTenant with fvBD and fvAEPg children - and POST it to /api/mo/uni.json. APIC creates the hierarchy in dependency order, so no second call is required; verify with a GET on /api/mo/uni/tn-Prod.json?rsp-subtree=children. If a script must re-run safely, query the objects first and only POST what is missing.

Traps that cost marks

  • GETting /api/mo/uni.json with no filter on a production APIC - enormous, slow response.
  • Confusing DN (absolute path) with RN (relative name) when composing URLs.
  • Using GET to configure, or omitting the JSON content type.
  • Ignoring token lifetime, or scripting NX-API with the wrong type for configuration.