If anyone has seen my previous post about using Lets Encrypt open source certificates with Azure Stack Hub may remember that those certs have a 90 day lifetime. This means that if you do use them, you’ll need to rotate your certificates on a more regular cadence than the normal 1 year with paid for third party cert authorities. For me, this isn’t a problem as it adds only a small amount of overhead to managing my stamps, assisted by helper scripts to generate the certs and some clear documentation on the process for rotating the core infra SSL Certs (found here).
What isn’t so clear is how to rotate the certs for your App Service PaaS infrastructure. I haven’t found any easily findable (is that a word?) reference to it in the online documentation. Not to worry, it’s actually a fairly simple process and I’ve recorded step-by-step how to perform it.
One thing I’ll point out first - you won’t find any alerts regarding impending App Service certificates expiration like you do with the core infrastructure, so you’ll have to make a note in your calendar for a suitable date to renew your certs, or just periodically check the admin portal.
From the Admin Portal, open up the App Service blade
Open the Secrets blade
From here you can check how many days you have left until your certs expire. As you can see in my case I have 11 days, so time to rotate!
Selecting the Rotate button brings up a new blade. From here you provide the locations of the Default App Service pfx cert, API pfx, FTP (or publishing) pfx and the SSO (or Identity Application) pfx, along with the corresponding passwords for these files.
Once you have entered these details and clicked OK, the Certificate Rotation status window will show you the progress of the task
You can navigate from this screen and do other tasks if you want. You can click on the Status button to check on the progress.
What you should see if the details you entered were validated.
Success!
The whole process took between 15-20 minutes. I wasn’t sure as I went and got a coffee!
Just to check that the certificates have actually been updated, I refreshed the Secrets blade and saw that the expiry was now 90 days, per the new Lets Encrypt certs I created.
Hopefully this is of some use to fellow Azure Stack Hub operators who haven’t had to update their App Service Certs yet, and remember, you won’t be alerted if they do expire!