Part three: Ansible URI module and PUT or POST

This will be the last part of my short series on the Ansible URI module and this time I will explain and show examples about when to use PUT or POST when interacting with REST APIs. I make use of the JSON_QUERY filter which I have explained in my previous article.

What is the difference between POST and PUT?

  • PUT – The PUT method is idempotent and needs the universal unique identifier (uuid) to update an API object. Example PUT /api/service/{{ object-uuid }}. The HTTP return code is 200.

  • POST – Is not idempotent and used to create an API object and an unique identifier is not needed for this. In this case the uuid is server-side generated.  Example POST /api/service/. The HTTP return code is 201.

I am again using the example from AVI Network Software Load Balancers and their REST API.

---
password: 123
api_version: 17.2.13
openshift:
  name: openshift-cloud-provider
openshift_cloud_json: "{{ lookup('template','openshift_cloud_json.j2') }}"

(Optional) Set ansible_host variable to IP address. I have had issues in the past using the DNS name and the task below overrides the variable with the IP address of the host:

- block:
  - name: Resolve hostname
    shell: dig +short "{{ ansible_host }}"
    changed_when: false
    register: dig_output
  
  - name: Set ansible_host to IP address
    set_fact:
      ansible_host: "{{ dig_output.stdout }}"
  when: ( inventory_hostname == groups ["controller"][0] )

Let’s start creating an object using POST and afterwards updating the existing object using PUT. The problem with POST is, that it is not idempotent so we need to first check if the object exists before creating it. We need to do this because creating the same object twice could be an issue:

- block: 
  - name: Avi | OpenShift | Check cloud config
    uri:
      url: "https://{{ ansible_host }}/api/cloud/?name={{ openshift.name }}" 
      method: GET 
      user: "{{ username }}" 
      password: "{{ password }}" 
      return_content: yes 
      body_format: json 
      force_basic_auth: yes 
      validate_certs: false 
      status_code: 200 
      timeout: 180 
      headers:
        X-Avi-Version: "{{ api_version }}" 
    register: check

  - name: Avi | OpenShift | Create cloud config
    uri:
      url: "https://{{ ansible_host }}/api/cloud/" 
      method: POST 
      user: "{{ username }}" 
      password: "{{ password }}" 
      return_content: yes 
      body: "{{ openshift_cloud_json }}" 
      body_format: json 
      force_basic_auth: yes 
      validate certs: false 
      status_code: 201 
      timeout: 180 
      headers:
        X-Avi-Version: "{{ api_version }}"
    when: check.json.count == 0 
  when: ( inventory_hostname == groups ["controller"][0] ) and update_config is undefined

Let’s continue with the example and using PUT to update the configuration of an existing object. To do this you need to define a extra variable update_config=true for the tasks below to be executed:

- block: 
  - name: Avi | OpenShift | Check cloud config
    uri:
      url: "https://{{ ansible_host }}/api/cloud/" 
      method: GET 
      user: "{{ username }}" 
      password: "{{ password }}" 
      return_content: yes 
      body_format: json 
      force_basic_auth: yes 
      validate_certs: false 
      status_code: 200 
      timeout: 180 
      headers:
        X-Avi-Version: "{{ api_version }}" 
    register: check

  - name: Avi | Set_fact for OpenShift name 
    set_fact:
      openshift_cloud_name: "[?name=='{{ openshift.name }}').uuid"
      
  - name: Avi | Set_fact for OpenShift uuid
    set_fact:
      openshift_cloud_uuid: "{{ check.json.results | json_query(penshift_cloud_name) }}" 
      
  - name: Avi | OpenShift | Update cloud config
    uri:
      url: "https://{{ ansible_host }}/api/cloud/{{ openshift_cloud_uuid [0] }}" 
      method: PUT 
      user: "{{ username }}" 
      password: "{{ password }}" 
      return_content: yes 
      body: "{{ openshift_cloud_json }}" 
      body_format: json 
      force_basic_auth: yes 
      validate_certs: false 
      status_code: 200 
      timeout: 180 
      headers:
        X-Avi-Version: "{{ api_version }}" 
    when: ( inventory_hostname == groups ("controller"][0] ) and update_config is defined

Here you find the links to the other articles about Ansible URI module:

Please share your feedback and leave a comment.

Part two: Ansible URI module and json_query filter

In my previous article I tried to explain how to use the Ansible URI Module and using the Jinja2 template engine to generate the JSON content. In part two I want to explain how to use the json_query filter. I will use the example with AVI Networks Load Balancers but this can be with any device with an REST API.

First we need to get the output from two objects, for both we don’t know the UUIDs and the first two tasks are to collect the configuration from the API using GET and register the output:

- block:
  - name: Avi | Get OpenShift cloud configuration
    uri:
      url: "https://{{ ansible_host }}/api/cloud/"
      method: GET
      user: "{{ avi_username }}"
      password: "{{ avi_password }}"
      return_content: yes
      force_basic_auth: yes
      validate_certs: false
      status_code: 200
      timeout: 180
      headers:
        X-Avi-Version: "{{ api_version }}"
    register: openshift_cloud 
   
  - name: Avi | Get OpenShift Service Engine group
    uri:
      url: "https://{{ ansible_host }}/api/serviceenginegroup/"
      method: GET
      user: "{{ avi_username }}"
      password: "{{ avi_password }}"
      return_content: yes
      force_basic_auth: yes
      validate_certs: false
      status_code: 200
      timeout: 180
      headers:
        X-Avi-Version: "{{ api_version }}"
    register: openshift_segroup
  when: '( inventory_hostname == groups["controller"][0] )'

The two variables openshift_cloud and openshift_segroup contain JSON content with all configuration details. For the OpenShift cloud object I don’t know the UUID, the only reference is the object name “OpenShift Cloud” which I know because I had previously created the object. I am using the Ansible module Set_Fact for specifying the query and writing the output into a new variable openshift_cloud_uuid:

- block:
  - name: Avi | set_fact for OpenShift cloud query
    set_fact:
      openshift_cloud_query: "[?name=='OpenShift Cloud'].uuid"
  
  - name: Avi | set_fact for OpenShift UUID
    set_fact:
      openshift_cloud_uuid: "{{ openshift_cloud.json.results | json_query(openshift_cloud_query) }}"
  when: '( inventory_hostname == groups["controller"][0] )' 

We now have the openshift_cloud_uuid of the OpenShift cloud configuration so let’s continue with the second object of the Service Engine group which is trickier because I don’t know the UUID or the object name. The Service Engine group was automatically set-up in the background when the OpenShift cloud object got created but I know the reference to the OpenShift cloud object and I use the json_query filter and set_fact again:

- block:
  - name: Avi | set_fact for Service Engine group query
    set_fact:
      openshift_segroup_query: "[?cloud_ref=='https://{{ ansible_host }}/api/cloud/{{ openshift_cloud_uuid[0] }}'].uuid"
  
  - name: Avi | set_fact for Service Engine group UUID
    set_fact:
      openshift_segroup_uuid: "{{ openshift_segroup.json.results | json_query(openshift_segroup_query) }}"
  when: '( inventory_hostname == groups["controller"][0] )'

Right now we know the openshift_cloud_uuid and the openshift_segroup_uuid, we use this to load a new Jinja2 template to update the Service Engine group object. See below the Jinja2 template openshift_segroup_json.j2:

{
  ...
  "name": "Default-Group",
  "tenant_ref": "https://{{ ansible_host }}/api/tenant/admin",
  "cloud_ref": "https://{{ ansible_host }}/api/cloud/{{ openshift_cloud_uuid[0] }}",
  ...
  YOUR CHANGES
  ...
}

The last part of this exercise is to load the j2 template and push the json content against the API to update the object using PUT:

- block:
  - name: Avi | set_fact to load Service Engine group json template
    set_fact:
      openshift_segroup_json: "{{ lookup('template', 'openshift_segroup_json.j2') }}"
  
  - name: Avi| Update OpenShift Service Engine group configuration
    uri:
      url: "https://{{ ansible_host }}/api/serviceenginegroup/{{ openshift_segroup_uuid[0] }}"
      method: PUT
      user: "{{ avi_username }}"
      password: "{{ avi_password }}"
      return_content: yes
      force_basic_auth: yes
      validate_certs: false
      body: "{{ openshift_segroup_json }}"
      body_format: json
      status_code: 200
      timeout: 180
      headers:
        X-Avi-Version: "{{ api_version }}"
  when: '( inventory_hostname == groups["controller"][0] )'

I hope this article is helpful on how to use the Ansible URI module and the json_query filter to extract information and update an API object. Please share your feedback and leave a comment.

Here you find the links to the other articles about Ansible URI module:

How to delegate Ansible host variables with set_fact

I ran into an interesting issues about making an service account token on OpenShift accessible by another group of nodes when running a playbook. When you run an oc command and register the output, you face the issue that the registered variable is stored under hostvars of the node name.

Normally you can access hostvars from other nodes like you see below:

"{{ hostvars['hostname']['variable-name'] }}"

I came up with something different and more flexible, instead of accessing hostvars[‘hostname’][‘variable-name’] I am delegating the variable to a group of nodes and make the variable more easily accessible there:

---
- hosts: avi-controller:masters
  gather_facts: false

  pre_tasks:
    - block:
      - name: Get OpenShift token
        command: "oc sa get-token <serveraccount-name> -n <project-name> --config=/etc/origin/master/admin.kubeconfig"
        register: token

      - name: Set serviceaccount token variable and delegate
        set_fact:
          serviceaccount_token: "{{ token.stdout }}"
        delegate_to: "{{ item }}"
        delegate_facts: true
        with_items: "{{ groups['avi-controller'] }}"
      when: ( inventroy_hostname == groups["masters"][0] )
 
 roles:
    - { role: "config", when: "'avi-controller' in group_names" }

In the following Ansible role after pre tasks, you are able to access the variable serviceaccount_token on any member of the group “avi-controller” and use with the rest of your automation code.

If you like this article, please share your feedback and leave a comment.

OpenShift Infra node “Not Ready” running Avi Service Engine

I had to troubleshoot an interesting issue with OpenShift Infra nodes suddenly going into “Not Ready” state during an OpenShift upgrade or not registering on Master nodes after a re-install of OpenShift cluster. On the Infra nodes Avi Service Engines were running for ingress traffic. The problem was not very obvious and RedHat and Avi Networks were not able to identify the issue.

Here the output of oc get nodes:

[[email protected] ~]# oc get nodes -o wide --show-labels | grep 'region=infra'
infra01   NotReady                   1d        v1.7.6+a08f5eeb62           Red Hat Enterprise Linux Server 7.6 (Maipo)   3.10.0-693.11.6.el7.x86_64   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=Standard_D8_v3,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=uksouth,failure-domain.beta.kubernetes.io/zone=1,kubernetes.io/hostname=infra01,logging-infra-fluentd=true,purpose=infra,region=infra,zone=1
infra02   NotReady                   1d        v1.7.6+a08f5eeb62           Red Hat Enterprise Linux Server 7.6 (Maipo)   3.10.0-693.11.6.el7.x86_64   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=Standard_D8_v3,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=uksouth,failure-domain.beta.kubernetes.io/zone=1,kubernetes.io/hostname=infra02,logging-infra-fluentd=true,purpose=infra,region=infra,zone=0
infra03   NotReady                   1d        v1.7.6+a08f5eeb62           Red Hat Enterprise Linux Server 7.6 (Maipo)   3.10.0-693.11.6.el7.x86_64   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=Standard_D8_v3,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=uksouth,failure-domain.beta.kubernetes.io/zone=0,kubernetes.io/hostname=infra03,logging-infra-fluentd=true,purpose=infra,region=infra,zone=2
[[email protected] ~]#

On the Infra node itself you could see that the atomic node service had successfully started but I saw a very strange error message from the kubelet not being able to synchronise the pod:

I1206 14:52:28.115735   21690 cloud_request_manager.go:89] Requesting node addresses from cloud provider for node "infra01"
I1206 14:52:28.170366   21690 cloud_request_manager.go:108] Node addresses from cloud provider for node "infra01" collected
E1206 14:52:28.533560   21690 eviction_manager.go:238] eviction manager: unexpected err: failed GetNode: node 'infra01' not found
I1206 14:52:32.840769   21690 kubelet.go:1808] skipping pod synchronization - [Kubelet failed to get node info: failed to get zone from cloud provider: Get http://169.254.169.254/metadata/v1/InstanceInfo: dial tcp 169.254.169.254:80: getsockopt: no route to host]
I1206 14:52:37.841235   21690 kubelet.go:1808] skipping pod synchronization - [Kubelet failed to get node info: failed to get zone from cloud provider: Get http://169.254.169.254/metadata/v1/InstanceInfo: dial tcp 169.254.169.254:80: getsockopt: no route to host]
I1206 14:52:38.170604   21690 cloud_request_manager.go:89] Requesting node addresses from cloud provider for node "infra01"
I1206 14:52:38.222439   21690 cloud_request_manager.go:108] Node addresses from cloud provider for node "infra01" collected
E1206 14:52:38.545991   21690 eviction_manager.go:238] eviction manager: unexpected err: failed GetNode: node 'infra01' not found
I1206 14:52:42.841547   21690 kubelet.go:1808] skipping pod synchronization - [Kubelet failed to get node info: failed to get zone from cloud provider: Get http://169.254.169.254/metadata/v1/InstanceInfo: dial tcp 169.254.169.254:80: getsockopt: no route to host]
I1206 14:52:47.841819   21690 kubelet.go:1808] skipping pod synchronization - [Kubelet failed to get node info: failed to get zone from cloud provider: Get http://169.254.169.254/metadata/v1/InstanceInfo: dial tcp 169.254.169.254:80: getsockopt: no route to host]

Even stranger is that the kubelet was not able to get the metadata information of the Azure Cloud provider with the fault domain in which the instance is running.

About the “no route to host” error I thought this must be a network issue and that I could reproduce this with a simple curl command:

[[email protected] ~]# curl -v http://169.254.169.254/metadata/v1/InstanceInfo
* About to connect() to 169.254.169.254 port 80 (#0)
*   Trying 169.254.169.254...
* No route to host
* Failed connect to 169.254.169.254:80; No route to host
* Closing connection 0
curl: (7) Failed connect to 169.254.169.254:80; No route to host
[[email protected] ~]#

The routing table on the node looked fine and theoretically forwarded the traffic to the default gateway in the subnet.

[[email protected] ~]# ip route show
default via 10.1.1.1 dev eth0
10.1.1.0/27 dev eth0 proto kernel scope link src 10.1.1.10 
10.128.0.0/15 dev tun0 scope link
10.128.0.0/15 dev tun0
168.63.129.16 via 10.1.1.1 dev eth0 proto static
169.254.0.0/16 dev eth0 scope link metric 1002
169.254.169.254 via 10.1.1.1 dev eth0 proto static
172.17.0.0/16 via 172.17.0.1 dev docker0
172.18.0.0/16 dev bravi proto kernel scope link src 172.18.0.1
[[email protected] ~]#

What was a bit strange when I used tracepath was that the packets weren’t forwarded to the default gateway but instead forwarded to the node itself:

[[email protected] ~]# tracepath 169.254.169.254
1?: [LOCALHOST]                                         pmtu 1500
1:  infra01                                     3006.801ms !H
    Resume: pmtu 1500

Same with traceroute or ping output:

[[email protected] ~]# traceroute 169.254.169.254
traceroute to 169.254.169.254 (169.254.169.254), 30 hops max, 60 byte packets
1  infra01 (172.18.0.1)  1178.146 ms !H  1178.104 ms !H  1178.057 ms !H
[[email protected] ~]# ping 169.254.169.254
PING 169.254.169.254 (169.254.169.254) 56(84) bytes of data.
From 172.18.0.1 icmp_seq=1 Destination Host Unreachable
From 172.18.0.1 icmp_seq=2 Destination Host Unreachable
From 172.18.0.1 icmp_seq=3 Destination Host Unreachable
From 172.18.0.1 icmp_seq=4 Destination Host Unreachable
^C
--- 169.254.169.254 ping statistics ---
5 packets transmitted, 0 received, +4 errors, 100% packet loss, time 4000ms
pipe 4

What was very obvious was that the packets were forwarded to the bravi bridge 172.18.0.0/16 which is owned by the Avi Service Engine on the Infra node:

...
44: bravi: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000
   link/ether 00:00:00:00:00:01 brd ff:ff:ff:ff:ff:ff
   inet 172.18.0.1/16 scope global bravi
      valid_lft forever preferred_lft forever
   inet6 fe80::200:ff:fe00:1/64 scope link
      valid_lft forever preferred_lft forever
45: bravi-tap: <BROADCAST,MULTICAST> mtu 1500 qdisc noop master bravi state DOWN qlen 1000
   link/ether 00:00:00:00:00:01 brd ff:ff:ff:ff:ff:ff
...

Here is the article about how Avi SE are integrated into the OpenShift SDN. Avi uses PBR (policy based routing) to forward external ingress traffic to the Service Engine.

I have turned off the bravi bridge because PBR could be bypassing the routing table for traffic to the 169.254.169.254.

[[email protected] ~]# ip link set bravi down

Traffic is now exiting the Infra node:

[[email protected] ~]# traceroute 169.254.169.254
traceroute to 169.254.169.254 (169.254.169.254), 30 hops max, 60 byte packets
1  * * *
2  * * *
3  * * *
4  * * *
5  * * *
6  *^C
[[email protected] ~]#

And the Infra node was able to collect metadata information:

[[email protected] ~]# curl -v http://169.254.169.254/metadata/v1/InstanceInfo
* About to connect() to 169.254.169.254 port 80 (#0)
*   Trying 169.254.169.254...
* Connected to 169.254.169.254 (169.254.169.254) port 80 (#0)
GET /metadata/v1/InstanceInfo HTTP/1.1
User-Agent: curl/7.29.0
Host: 169.254.169.254
Accept: */*

< HTTP/1.1 200 OK
< Content-Type: text/json; charset=utf-8
< Server: Microsoft-IIS/10.0
< Date: Thu, 06 Dec 2018 13:53:16 GMT
< Content-Length: 43
<
* Connection #0 to host 169.254.169.254 left intact
{"ID":"_infra01","UD":"4","FD":"0"}
[[email protected] ~]#

Simple restart of the atomic node service to trigger the master registration:

[[email protected] ~]# systemctl restart atomic-openshift-node

The logs showed that the kubelet successfully got zone information

Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.341611   36813 kubelet_node_status.go:270] Setting node annotation to enable volume controller attach/detach
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.414847   36813 kubelet_node_status.go:326] Adding node label from cloud provider: beta.kubernetes.io/instance-type=Standard_D8_
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.414881   36813 kubelet_node_status.go:337] Adding node label from cloud provider: failure-domain.beta.kubernetes.io/zone=0
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.414890   36813 kubelet_node_status.go:341] Adding node label from cloud provider: failure-domain.beta.kubernetes.io/region=ukso
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.414966   36813 kubelet_node_status.go:488] Using Node Hostname from cloudprovider: "infra01"
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.420823   36813 kubelet_node_status.go:437] Recording NodeHasSufficientDisk event message for node infra01
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.420907   36813 kubelet_node_status.go:437] Recording NodeHasSufficientMemory event message for node infra01
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.423139   36813 kubelet_node_status.go:437] Recording NodeHasNoDiskPressure event message for node infra01
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.423235   36813 kubelet_node_status.go:82] Attempting to register node infra01
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.435412   36813 kubelet_node_status.go:85] Successfully registered node infra01
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.437308   36813 kubelet_node_status.go:488] Using Node Hostname from cloudprovider: "infra01"
Dec 07 16:03:21 infra01 atomic-openshift-node[36736]: I1207 16:03:21.441482   36813 manager.go:311] Recovery completed

The Infra node successfully registered again the OpenShift master and the node went into “Ready”:

[[email protected] ~]# oc get nodes -o wide --show-labels | grep 'region=infra'
infra01   Ready                      40s       v1.7.6+a08f5eeb62           Red Hat Enterprise Linux Server 7.6 (Maipo)   3.10.0-693.11.6.el7.x86_64   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=Standard_D8_v3,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=uksouth,failure-domain.beta.kubernetes.io/zone=0,kubernetes.io/hostname=infra01,logging-infra-fluentd=true,purpose=infra,region=infra,zone=1
infra02   Ready                      1d        v1.7.6+a08f5eeb62           Red Hat Enterprise Linux Server 7.6 (Maipo)   3.10.0-693.11.6.el7.x86_64   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=Standard_D8_v3,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=uksouth,failure-domain.beta.kubernetes.io/zone=1,kubernetes.io/hostname=infra02,logging-infra-fluentd=true,purpose=infra,region=infra,zone=0
infra03   Ready                      1d        v1.7.6+a08f5eeb62           Red Hat Enterprise Linux Server 7.6 (Maipo)   3.10.0-693.11.6.el7.x86_64   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/instance-type=Standard_D8_v3,beta.kubernetes.io/os=linux,failure-domain.beta.kubernetes.io/region=uksouth,failure-domain.beta.kubernetes.io/zone=0,kubernetes.io/hostname=infra03,logging-infra-fluentd=true,purpose=infra,region=infra,zone=2
[[email protected] ~]#

In the end, the root cause was the Avi East West subnet range which was set to 169.254.0.0/16 on the Avi controller nodes. Even the East West communication was deactivated on Avi, because kube_proxy was used, which made the Avi controller configure PBR on the bravi bridge for the 169.254.0.0/16 subnet range. This subnet range was previously used on all the on-prem datacenters and never caused issues since moving to cloud because the 169.254.169.254 is commonly used on cloud provider for instances to collect metadata information.

Part one: Ansible URI module and Jinja2 templating

This article about the Ansible URI module. I have recently spend a lot of time around automation for AVI software defined load balancers and wanted to share some useful information about how to use Ansible to interacting with REST API’s. Please check out my other articles around AVI Networks.

Let’s start with the playbook:

---
- hosts: controller
  gather_facts: false
  roles:
    - { role: "config" }

The config role needs the following folders:

config/
├── defaults    # Useful for default variables
├── tasks       # Includes Ansible tasks using the URI module
├── templates   # Jinja2 json templates
└── vars        # Variables to load json j2 templates

I will use defaults just as an example for variables which I use in the task and the json template.

Here’s the content of defaults/main.yml:

---
dns_servers:
  - 8.8.8.8
  - 8.8.4.4
dns_domain: domain.com
ntp_servers:
  - 0.uk.pool.ntp.org
  - 1.uk.pool.ntp.org
username: admin
password: demo
api_version: 17.2.11

Next the Json Jinja2 template, the example below is the system configuration from AVI load balancers but this can be any json content you want to push to a REST API, templates/systemconfiguration_json.j2:

{
  "dns_configuration": {
    {% if dns_domain is defined %}
    "search_domain": "{{ dns_domain }}"
    {% endif %}
    {% if dns_servers is defined %}
    {% for item in dns_servers %}
    "server_list": [
      {
         "type": "V4",
         "addr": "{{ item }}"
      }
      {% if not loop.last %}
      ,
      {% endif %}
      {% endfor %}
      {% endif %}
    ]
  },
  "ntp_configuration": {
    {% if ntp_servers is defined %}
    {% for item in ntp_servers %}
    "ntp_servers": [
      {
        "server": {
          "type": "DNS",
          "addr": "{{ item }}"
        }
      }
      {% if not loop.last %}
      ,
      {% endif %}
      {% endfor %}
      {% endif %}  
    ]
  },
  "portal_configuration": {
    "password_strength_check": true,
    "use_uuid_from_input": false,
    "redirect_to_https": true,
    "enable_clickjacking_protection": true,
    "enable_https": true,
    "disable_remote_cli_shell": false,
    "http_port": 80,
    "enable_http": true,
    "allow_basic_authentication": true,
  }
}

After we have specified the default variables and created the j2 template, let’s continue and see how we load the json template into a single variables in vars/main.yml:

---
systemconfiguration_json: "{{ lookup('template', 'systemconfiguration_json.j2') }}"

The step is the task itself using the Ansible URI module, tasks/main.yml:

---
- block:
  - name: Config | Systemconfiguration | Configure DNS, NTP and Portal settings
    uri:
      url: "https://{{ ansible_host }}/api/systemconfiguration"
      method: PUT
      user: "{{ username }}"
      password: "{{ password }}"
      return_content: yes
      body: "{{ systemconfiguration_json }}"
      force_basic_auth: yes
      validate_certs: false
      status_code: 200, 201
      timeout: 180
      headers:
        X-Avi-Version: "{{ api_version }}"
  when: '( inventory_hostname == group["controller"][0] )'

I like to use blocks in my Ansible tasks because you can group your tasks and use a single WHEN statement when you have multiple similar tasks.

I hope you find this article useful and please try it out and let me now in the comments below if you have questions.

Continue and read the other parts of this little series:

Here you find the links to the other articles about Ansible URI module: