Availability and uptime of Containers in Azure

Question

Our app (docker) responded with 503 Service Unavailable on Mar 23, 2021 (most of the day). The status page did not mention any services down and the Docker container did work again the next day. This is currently just a development test but it is not OK to be down for a day if this goes in production. How is the availability and uptime in general with containers on Azure?

Answer 1

@IDTF We apologize for the frustration that you encountered with receiving 503 errors on your service.

Without a formal investigation, it's difficult to say what the root cause of the 503 errors was. While 503 errors can indicate that the server is not available due to maintenance or upgrades, we typically see 503 errors originating from the chosen application framework (such as Asp.Net , PHP, Java etc.) and/or the application code written by the customer.

I checked March 22-24th and there were no formal outages declared that should have impacted service availability. That combined with the fact that you mentioned your application is in development, would start to make me believe that something within your application code caused the 503 errors but again, without a formal investigation, nothing can be determined as to the cause of the errors.

In regards to the Service Level Agreement (SLA) that is provided for Azure Web App Containers, is 99.95% uptime. Please keep in mind though that this will not cover downtime caused by customer code issues or customer misconfiguration. The SLA can be found here at the bottom of the chart (containers run on basic or higher tiers).

Please let us know if there are further questions or concerns.