Setting up Azure for Audit Trail
First you will need to create a user for Audit Trail.
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Set the directory roles for the user at Administrator level
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It may also be necessary to set the IAM role on the subscription for this user. From the Azure home page, select subscriptions. (If you do not see it as a link then search for it in the search box)
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Select your subscription, and then Access control (IAM)
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Under Add, select Add role assignment. On the Privileged administrator roles, select contributor.
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Select the next button, press select members and search for and select the user.
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Press Review + assign to give the users this role.