This is a continuation of an article that describes operational considerations for hosting solutions on Azure public cloud.

This articles focuses on support for containers and Kubernetes in Azure. 

Compute requirement of a modern cloud app typically involves load balanced compute nodes that operate together with control nodes and databases.

VM Scale sets provide scale, customization, availability, low cost and elasticity.

VM scale sets in Azure resource manager generally have a type and a capacity. App deployment allow VM extension updates just like OS updates.

Container infrastructure layering allows even more scale because it virtualizes the operating system. While traditional virtual machines enable hardware virtualization and hyper V’s allow isolation plus performance, containers are cheap and barely anything more than just applications.

Azure container service serves both linux and windows container services. It has standard docker tooling and API support with streamlined provisioning of DCOS and Docker swarm.

Azure is an open cloud because it supports open source infrastructure tools  such as  Linux, ubuntu, docker, etc. layered with databases and middleware such as hadoop, redis, mysql etc., app framework and tools such as nodejs, java, python etc., applications such as Joomla, drupal etc and management applications such as chef, puppet, etc. and finally with devops tools such as jenkins, Gradle, Xamarin etc.

Job based computations use larger sets of resources such as with compute pools that involve automatic scaling and regional coverage with automatic recovery of failed tasks and input/output handling.

Azure involves a lot of fine grained loosely coupled micro services using HTTP listener, Page content, authentication, usage analytic, order management, reporting, product inventory and customer databases.

 

Efficient Docker image deployment for intermittent low bandwidth connectivity scenarios requires the elimination of docker pulling of images. An alternative deployment mechanism can compensate for the restrictions by utilizing an Azure Container Registry, Signature Files, a fileshare, an IOT hub for pushing manifest to devices. The Deployment path involves pushing image to device which is containerized. The devices can send back messages which are collected in a device-image register. An image is a collection of layers where each layer represents a set of file-system differences and stored merely as folders and files. A SQL database can be used to track the state of what’s occurring on the target devices and the Azure based deployment services which helps with both during and after the deployment process.

 

Resource groups are created to group resources that share the same lifecycle. They have no bearing on the cost management of resources other than to help with querying. They can be used with tags to narrow down the interest. There is metadata stored about the resources and it is stored in a particular region. Resources can be moved from one resource group to another or even to another subscription. Finally, resource groups can be locked to prevent actions such as delete or write by users who have access.

As with its applicability to many deployments, Azure Monitor provides tremendous insight into operations of Azure Resources. It is always recommended to create multiple application insights resources and usually one per environment. This results in better separation of telemetry,alerts, workitems, configurations and permissions. Limits are spread such as web test count, throttling, data allowance etc and it also helps with cross-resource queries.

 

This is a continuation of an article that describes operational considerations for hosting solutions on Azure public cloud.

Multiple-choice questions in certification examinations are quite costly to make a mistake because they go beyond the cursory knowledge on the Azure resources. We recap just a few of the storage related questions from a recent test.

1.       The storage-based questions are somewhat easier to answer because they apply to a lot of common use cases. Some attention to limits imposed on different types of storage, their access polices, tiers, and retention period will go a long way in getting the answers right. Familiarity with hot, cool and archive tiers are tested by their use cases. Access control policy enforcement and cost management apply just as much they do for all Azure resources. Redundancy and availability are special considerations. Geo-replication is a hot topic.

2.       Hot, cool and archive access tiers for blob data are optimized for access patterns. The hot tier has the highest storage cost but the lowest access cost.  The cool tier stores for a minimum of 30 days and the archive tier for a minimum of 180 days. The archive tier is an offline tier for storing data with data rehydration available on standard and priority basis. The storage capacity costs Hot tier can be set to cool tier or archive tier and cool tier can be set to archive tier. If a blob is moved from the archive tier to the hot tier, it will be moved back to the archive tier by the lifecycle management engine. End-to-End latency and server latency are both available for block blobs.

3.       Azure storage events allow application to react to events such as the creation and deletion of blobs. They are pushed using Azure Event Grid to subscribers such as Azure Functions, Azure Logic Applications or even to the http listener. Blob storage events schema defines Microsoft.Storage.BlobCreated, BlobDeleted, BlobTierChanged and AsyncOperationInitiated.

4.       Network File System (NFS) 3.0 protocol is supported in Azure Blob Storage. Mounting a storage account container involves creating an Azure Virtual Network (VNet) and configuring network security to allow traffic to and from the storage account container via the VNet. Azurite open-source emulator can be used for local development environment.

5.       Azure (global) supports General Purpose V1, V2, and Blob storage accounts while Azure Stack Hub is general-purpose v1 only.  V2 is preferred because it provides Blob, queue, file and table storage with LRS, GRS, RA-GRS redundancy options

6.       Costs for storage tier is based on amount of data stored depending on the access tier, the data access cost, the transaction cost, the geo-replication data transfer cost, the outbound data transfer cost, and the changing storage access tier. The primary access pattern for the blob storage in terms of reads and writes and their comparisons determines the cost savings. All storage accesses can be monitored, and metrics emitted include capacity costs, transaction costs, and data transfer costs.

 

 

 

This is a continuation of an article that describes operational considerations for hosting solutions on Azure public cloud.

In this article, the topics that are encountered when taking certification examinations on Azure are discussed. The multiple-choice questions in those examinations are quite costly to make a mistake because they go beyond the cursory knowledge on the Azure resources. We recap just a few of these questions from a recent test.

Organizations deal with compute, storage and networking problems but identity hits home with the employees. Some of the questions ask about how inter-domain trust is established.  The order in which these steps are performed. The techniques by which multi-factor authentication is set up. How applications and services are secured. The scope at which these role-based access control may be overriden. How can the policies be conditionally enforced? These are some of the themes on which the questions from the certification examinations are based.

These questions are not hard to answer per se but they highlight the requirement for deep understanding of the Azure resources for solving those problems. For example, it finds out when password sync and password pass-through are applicable. Similarly, the use of privileged user protection is questioned.

The storage-based questions are somewhat easier to answer because they apply to a lot of common use cases. Some attention to limits imposed on different types of storage, their access polices, tiers, and retention period will go a long way in getting the answers right. Familiarity with hot, cool and archive tiers are tested by their use cases. Access control policy enforcement and cost management apply just as much they do for all Azure resources. Redundancy and availability are special considerations. Geo-replication is a hot topic.

The compute-based questions apply to different size and scale required for small, mid and large usages. They apply to different use cases but a common topic of interest is interoperability or dedicated ecosystems. It is important to know how to use them but it is more important to know how it connects to Azure resources including its hardening. Some examples cited in the questions span container orchestration frameworks, container registries and instances.

The networking questions are heavy on connections and their restrictions. VPN, firewall, Bastion are discussed in examples from threat analysis and mitigation purposes. The way to author policies, rules, routes and circuits are discussed very well.

Lastly. a study of the documentation online on architecture and best practices will round up the preparation.

 

 

This is a continuation of an article that describes operational considerations for hosting solutions on Azure public cloud.

The order in which a conditional access policy is implemented depends on the assignments and access controls. It brings together signals with which it makes decisions and then enforces organizational policies. If there are multiple conditional access policies, they must all apply to grant access. Assignments such as requiring an MFA and a compliant device must be ANDed. Policies are enforced in two phases: 1) session details are collected and 2) policies are enforced. Phase 1 involves gathering session details via connection properties which are also evaluated in report-only mode Phase 2 prompts the user but enforces all the policies.

Azure AD conditional access is frequently used to secure cloud applications with a single policy that grants access for selected users and groups who are required to pass multi-factor authentication. This comes helpful when access is originated from a location that is not trusted.

Networking resources must belong to the same subscription, region and resource group to set up virtual end points.  Microsoft peering must be created to configure ExpressRoute circuit. The provider status is checked to ensure that the circuit is fully provisioned by the connectivity provider.

Azure Monitors provide tremendous insight into operations of Azure Resources. It is always recommended to create multiple application insights resources and usually one per environment. This results in better separation of telemetry,alerts, workitems, configurations and permissions. Limits are spread such as web test count, throttling, data allowance etc and it also helps with cross-resource queries.

Limits should not be configured for the prod environment because it will result in loss of data once the limits are breached. They apply instead to dev and test environments.

When the data does not show in the telemetry, we could check the firewall practice, ikey configurations, user account under which the IIS is running and if it has privileges to access the internet. The Flush method can be called periodically.

Status Monitor tool can be used when the app is instrumented with the .Net 4.6 SDK. It collects basic information about outbound HTTP and SQL calls. Alert should not be configured unnecessarily. They could generate a lot of noise and make it harder to detect those that matter. RBAC controls must be properly set as with all resources.

 

 

This is a continuation of an article that describes operational considerations for hosting solutions on Azure public cloud.

Log analytics workspace does not always follow a one-size-fits-all. These map to the Centralized, Decentralized or Hybrid structures of IT in the organizations.  In the case of centralized IT infrastructure, all logs are stored in a centralized workspace and administered by a single team, with Azure Monitor providing differentiated access per team. This is an easy solution to manage. It helps with searching across resources and cross-correlating logs. The decentralized department or teams run their own workspaces in a resource group they own and manage. Even in this case, the workspace can be kept secure and access control can be kept consistent with resource access, but it is difficult to cross-correlate logs without involving third-party log indexes. Without a combined index, every addition of a workspace will require a rewrite of the queries. In the hybrid environment, both deployments are deployed in parallel. The hybrid case results in complex, expensive and hard to maintain configuration. The log analytics workspace can be in any region, but the destination storage account or event hub must be in the same region as the Log Analytics workspace. The jump from centralized to decentralized log analytics workspace is warranted when cross-correlation queries are not required.

In all these cases, access to data logs and workspaces must be managed. The workspace must be managed using workspace permissions. Users who need access to log data from specific resources can be granted permission using Azure role-based access control (Azure RBAC) and those who need access to specific tables in the workspace can have restrictive access. The access control mode can be configured on a workspace from Azure Portal.

The workspace context and resource context have different access. All logs in the workspace can be accessed with the workspace context. The Resource context is aimed at Application teams. Administrators of Azure resources that are monitored can be granted access. The view for these users gets restricted based on their role and scope.

The Azure Monitor has an ingestion pipeline as well as the Log Analytics workspace. It is possible to set it up with a central Storage Account. The incoming data feeds the ingestion pipeline which then sends the data to the storage account or the Event Hub.

Design decisions depend on factors such as whether a central location with all data is required and should there be one workspace per application or each team manages their own workspaces. Data Location, data retention, data access, and data collection must be decided for a streamlined data path. A good data path will be short and clean.

 

 

 

This is a continuation of an article that describes operational considerations for hosting solutions on Azure public cloud.

Some of the best practices for Azure Container Registry include Network-close deployment, geo-replicated multi-region deployments, maximized pull performance, repository namespaces, dedicated resource group, individual and headless authentication and authorization and management of registry size.

When the registry is created in the same region as where the containers are deployed, the closeness of the registry to the host in terms of network helps lower latency and cost. Availability is improved with further enhancing the region to be zone redundant. Docker images have a layering construct which facilitates incremental deployments, but new nodes need to pull all layers defined in the dockerfile. Since there are many fetches, the network RTT matters to the design.

Multi-region deployments could leverage geo-replication which simplifies registry management and minimizes latency.  It is also configured to use regional webhook which notifies us of events in specific replicas when images are pushed.

The pull-performance can be maximized by reducing the image size and the number of layers. The former is achieved by removing unnecessary layers and the use of multi-stage Docker build. Base images can be smaller when the alpine version is used. The number of layers should ideally be between 5-10.

The repository namespaces allow sharing a single registry with multiple groups within your organization. Nested namespaces support group isolation but a flat list of repositories is preferred.

Resource groups tie resource lifetimes. A Registry should reside in its own resource group. Azure container instances, on the other hand, can be created or deleted as necessary.

When an individual uses the registry, the preferred way to authenticate is to use “az acr login”. When a build and deployment pipeline authenticate, it can use a server principal.

The storage for container registry must align with a typical scenario, standard for most production applications and premium for improved performance and geo-replication.

An Azure Function helps to create and delete the Container Instance in the time needed or get the state or message from a container instance.

Some like to use tag as ‘Latest’ when pulling images but using a specific version eliminates uncertainty and falls back on tried and tested deployments.

 

 

 

 This is a continuation of an article that describes operational considerations for hosting solutions on Azure public cloud.

1. Azure (global) supports FileStorage. Azure Stack Hub does not support.

2. Azure (global) supports General Purpose V1, V2, and Blob storage accounts while Azure Stack Hub is general-purpose v1 only. Prefer V2 because it provides Blob, queue, file and table storage with LRS, GRS, RA-GRS redundancy options

3. Azure Resource Manager provides options for moving a resource to a different subscription or a different resource group. ARM deployments come with full-fledged functionality, scalability and security. 

4. If a storage account must be moved, then it must first be copied and then AzCopy can be used to move the data.

5. When an application is migrated to Azure, its storage can remain the same format as before. For example, if file storage was used, NFSv3 can continue to be used by using Azure Storage V2.

6. General-purpose v2 accounts deliver the lowest per-gigabyte capacity prices for Azure Storage, as well as industry-competitive transaction prices. General-purpose v2 accounts support default account access tiers of hot or cool and blob level tiering between hot, cool, or archive.

7. Archive storage tier does not provide immediate data access. That can take hours to rehydrate. If we need immediate access, change the access tier to hot or cool. A v1 storage account can be upgraded to either hot or cool storage tier.

8. Costs for storage tier is based on amount of data stored depending on the access tier, the data access cost, the transaction cost, the geo-replication data transfer cost, the outbound data transfer cost, and the changing storage access tier. The primary access pattern for the blob storage in terms of reads and writes and their comparisons determines the cost savings. All storage accesses can be monitored, and metrics emitted include capacity costs, transaction costs, and data transfer costs.

9. Elastic pools can help manage and scale multiple databases in Azure SQL Database.  Traditionally, there were two options: over-provision resources based on peak usage and overpay, or Under-provision to save cost, at the expense of performance and customer satisfaction during peaks. Elastic pools solve this problem by ensuring that databases get the performance resources they need when they need it. They provide a simple resource allocation mechanism within a predictable budget

10. Conditional access policies can be leveraged on Azure resources to enforce criteria from security standpoint. For example, if we wanted to configure MFA on all user authentication, we would set it on the Azure AD as the MFA conditional access. Common conditional access policies involve blocking legacy authentications and requiring MFA for all users.

11. On the other hand, the Privileged Identity Management is a service from Azure AD that can help with management, control and monitoring of important resources in the organization. It provides just in time privileged access to Azure resources such as storage accounts, assigns time-bound access and requires approval. It can also enforce MFA to activate any role.

12. B2B collaboration can be setup with Azure AD. External users can be invited as a guest but they must authenticate against their home organization so they can’t have access as a guest if they no longer have access to their home organization.

13. Securing privileged access for hybrid and cloud deployments in Azure AD requires changes to processes as well as resources such as the use of host defenses, user account protections and identity management.