{"id":292,"date":"2021-01-11T18:24:07","date_gmt":"2021-01-11T17:24:07","guid":{"rendered":"https:\/\/nine30.info\/?p=292"},"modified":"2021-01-11T18:24:07","modified_gmt":"2021-01-11T17:24:07","slug":"auto-scale-application-with-vrealize-automation-and-vrealize-operations","status":"publish","type":"post","link":"https:\/\/nine30.nxt70.com\/index.php\/2021\/01\/11\/auto-scale-application-with-vrealize-automation-and-vrealize-operations\/","title":{"rendered":"Auto-scale Application with vRealize Automation and vRealize Operations"},"content":{"rendered":"\n

I was requested to implement an auto-scale use case for a web application. Personally, I am not a fan of this auto-scale use case for some reasons, but elaborating on this could be the topic for a nice 9:30 chat with my friend Luca and possibly the subject for a new blog post. This entry in our blog is about how to configure auto-scale with vRealize solution family. What I like of this use case is that it gave me the chance to experiment with something I really like (vRA REST API<\/span><\/strong>) and dip my toes with something I am less familiar (vROps Alerts\/Policies and vRO Scriptable Tasks<\/strong><\/span>). For this specific lab I used version 8.2 of vRA\/vRO and vROps, but I am quite sure the same applies to 8.0 and 8.1 as well.<\/p>\n\n\n\n

The use case is about using vRA to deploy a web application that, in addition to other resources, presents one or more web server behind a load balancer. vROps monitors web server(s) load and if the load gets too higher for the current number of web servers it fires an alert that triggers a vRA deployment update day 2 action that increases the number of web servers. This is a scale-out scenario, a similar approach applies to the scale-in scenario<\/span><\/strong> that is triggered when load on web servers is lower than a given thresholds. Of course, in this second scenario the deployment update action reduces the number of web servers.<\/p>\n\n\n\n

This is a summary of the configurations I had to put together to implement the use case:<\/p>\n\n\n\n

  1. A VMware Cloud Template that deploys a web app with a configuration suitable for scale out\/in (load balancer and a clustered frontend web servers);<\/li>
  2. A vROps alert definition with a recommendation that automatically runs an action (vRO Workflow) when the alert is triggered;<\/li>
  3. A vRO Workflow that executes a vRA ABX action (this is basically a wrapper for a vRA REST API request);<\/li>
  4. A vRA ABX action that determines the new size of the cluster and update the right deployment accordingly.<\/li><\/ol>\n\n\n\n

    This could be implemented in many ways and certainly my approach is inefficient as points 3 and 4 in the list above could be implemented into a single vRO workflow.<\/p>\n\n\n\n

    OK, let\u2019s get started.<\/p>\n\n\n\n

    First things I needed was a VMware Cloud Template<\/span><\/strong> that deploys a web app with one or more web servers behind a load balancer. I am reusing a Cloud Template created by Chris McClanahan and his team, this template deploys a web app named OpenCart<\/em> (an open source ecommerce platform https:\/\/www.opencart.com\/<\/a>).<\/p>\n\n\n\n

    \n
    \"\"<\/figure>\n<\/figure>\n\n\n\n

    (Click on the image to enlarge)<\/p>\n\n\n\n

    Here the important point is that the template allows to have multiple VMs named frontend<\/em> behind a NSX-T load balancer<\/span><\/strong>. We control the number of fronted VMs by means of an input parameters named clusterSize<\/em> that can have the following values: small, medium and large.<\/p>\n\n\n\n

    clusterSize:\n  type: string\n  enum:\n    - small\n    - medium\n    - large\n  default: small\n  title: Frontend Cluster Size\n  description: Frontend Cluster Size<\/code><\/pre>\n\n\n\n
    Values of the clusterSize<\/em> parameter are mapped as follows: small is 1 VM, medium 2 VMs and large 4 VMs.<\/p>\n\n\n\n
    count: '${input.clusterSize == \"small\" ? 1 : (input.clusterSize == \"medium\" ? 2 : 4)}'<\/code><\/pre>\n\n\n\n
    Next I had to create an ABX action on VRA<\/span><\/strong>, I didn\u2019t started from scratch as along with the Cloud Template Chris passed to me a python script that does 60% of the work I need. Here is the logic of final script that lays behind the ABX action:<\/p>\n\n\n\n