The Azure Dictionary of Pain: Five Of Azure's Toughest ...

Today we’ll be covering five of the most challenging topics we identified for Azure infrastructure: Cosmos DB, Traffic Manager, Azure Functions, Snapshots, and Virtual Private Networks. This list is a subset of dozens of terms and topics we attacked across all three major cloud platforms: AWS, Microsoft Azure, and Google Cloud. You can find our complete walkthrough to Amazon’s thorny topics in the full Cloud Dictionary of Pain. … - **SESSION**: Ensures all read/write operations are consistent within a current user session. In a user session, for example, Facebook will have data particular to that user. - **CONSISTENT PREFIX**: This ensures changes are read in the sequence of the corresponding writes. - **EVENTUAL**: The loosest consistency, commits and writes against a primary immediately, and replicant transactions are synchronously handled and eventually get to replicas. … ### WHY IS IT HARD? Both Traffic Manager and Azure DNS work closely together to make sure your users are able to access your app and have a good experience. DNS is the phone book that contains IP addresses from the domain name, while Traffic Manager will pick the right IP from that list of IP addresses. In classic cloud fashion, there are a ton of routing methods that come with Traffic Manager. These are multiple types you’ll put into your Traffic Manager profile: - **PRIORITY**: prioritizes primary and backup endpoints. - **WEIGHTED**: distributes traffic according to weight value, such as if you’d like 20% to go to one region and 20% to another. - **PERFORMANCE**: sends traffic to the “closest” endpoint, which is excellent for solutions global in design. - **GEOGRAPHIC: ** route traffic based on the geographic location of the client. - **MULTIVALUE**: returns multiple endpoints, and up to the client to determine which endpoint to use. - **SUBNET**: route based on the requester’s IP address. You have to actually own the domain name. … - **MULTI-FACTOR**: Declarative and automated deployment (the function can be deployed via code), configuration is in the environment (not configuration files), concurrency is via the process. There are also many ways to execute a function: on time intervals, HTTP requests, whenever something is uploaded in Blob storage, a message from an Azure Storage queue, a Cosmos DB document change, or an event hub receiving a new event. … In addition, subnets within your Vnet are restricted to one availability zone rather than spanning multiple availability zones. As such, you’ll have to configure your systems in such a way to ensure you don’t run into a scenario where one subnet needs to be talking to another in a different availability zone.  *A Cloud Guru learners missed tough questions related to Vnets and subnets 49.8% of the time.*