Automated way to upgrade software on 500+ devices

I've been given the task of doing some software upgrades on over 500+ device. It is about a 50% split between Cisco and Juniper.

I'm thinking of automating as much as possible with Ansible and wanted to get others ideas on this.

My current thought process for what to automate is:

• Copying the appropriate file to the devices
• Running pre-checks
  • e,g, show version, show bgp/ospf info, show interfaces
• Running post-check
  • same as above

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I'm not sure if i want to actually kick off the install process via Ansible though. Since I usually do that via an out of band console server (opengear) so i can monitor the install process and check for errors.

So yeah wondering what other peoples thoughts are? Should i try and use Ansible to initiate the software install? If so, how would i check for errors?