Infrastructure Stability Report We are using Azure IAAS to host our applications, and these are hosted on a number of virtual machines for different tiers
Our client have recently asked us to provide monthly report on the Infrastructure Stability, so that they could know the health of the infrastructure and its availability during a given time period. 
Are there any standardized norms on how these reports should look like and what information it should contains, as we are not very clear on this and even client is not sure about the exact specifications.

We are currently using Zabbix for monitoring systems and thinking of using the same for these reports. Please suggest if there any tools available for Infrastructure Stability reporting and how we should approach it.
Its very common to provide a StatusPage (like Statusy.co or StatusPage.io). There are numerous examples of major providers having them:


https://status.github.com/messages
https://status.bitbucket.org/
https://status.aws.amazon.com/
https://azure.microsoft.com/en-us/status/
https://api.twitterstat.us/


You could provide the same status page to your customers. When there is a service disruption, you could manually update the status while providing detailed, customer-facing information. Or you could hook it into your Zabbix monitoring to have the status auto-updated.

This also lets your customers see a history of incidents and average uptime of your service.

There are also self-hosted, open-source solutions that you could implement:


https://cachethq.io/
http://www.stashboard.org/


Although, you'll really want to host those outside your existing infrastructure so that your StatusPage can always be reached, even if you're down. If you go the self-hosted route, I recommend hosting the status page at a different provider: Digital Ocean, AWS, etc...