June 17, 2024


“Adjustments to Azure providers and the Azure platform itself are each inevitable and helpful, to make sure steady supply of updates, new options, and safety enhancements. Nonetheless, change can be a main reason for service regressions that may contribute in the direction of reliability points—for hyperscale cloud suppliers, certainly for any IT service supplier. As such, it’s crucial to catch any such issues as early as attainable through the improvement and deployment rollout, to attenuate any impression on the client expertise. As a part of our ongoing Advancing Reliability weblog collection, immediately I’ve requested Principal Program Supervisor Jian Zhang from our AIOps staff to introduce how we’re more and more leveraging machine studying to de-risk these adjustments, finally to enhance the reliability of Azure.”—Mark Russinovich, CTO, Azure

This put up contains contributions from Principal Information Scientists Ken Hsieh and Ze Li, Principal Information Scientist Supervisor Yingnong Dang, and Associate Group Software program Engineering Supervisor Murali Chintalapati.


In our earlier weblog put up “Advancing protected deployment practices” Cristina del Amo Casado described how we launch adjustments to manufacturing, for each code and configuration adjustments, throughout the Azure platform. The processes encompass delivering adjustments progressively, with phases that incorporate sufficient bake time to permit detection at a small scale for many regressions missed throughout testing.

The continual monitoring of well being metrics is a elementary a part of this course of, and that is the place AIOps performs a crucial position—it permits the detection of anomalies to set off alerts and the automation of correcting actions akin to stopping the deployment or initiating rollbacks.

Within the put up that follows, we introduce how AI and machine studying are used to empower DevOps engineers, monitor the Azure deployment course of at scale, detect points early, and make rollout or rollback choices primarily based on impression scope and severity.

Why AIOps for protected deployment

As outlined by Gartner, AIOps enhances IT operations by insights that mix huge information, machine studying, and visualization to automate IT operations processes, together with occasion correlation, anomaly detection, and causality dedication. In our earlier put up, “Advancing Azure service high quality with synthetic intelligence: AIOps,” we shared our imaginative and prescient and a number of the methods during which we’re already utilizing AIOps in observe, together with round protected deployment. AIOps is nicely suited to catching failures throughout deployment rollout, significantly due to the complexities of cross-service dependencies, the size of hyperscale cloud providers, and the number of totally different buyer situations supported.

Phased rollouts and enriched well being alerts are used to facilitate monitoring and resolution making within the deployment course of, however the quantity of alerts and stage of complexity concerned in deployment resolution making exceeds what any human might moderately cause over, throughout 1000’s of ever-evolving service elements, spanning greater than 200 datacenters in additional than 60 areas. Some latent points gained’t manifest for a number of days after their deployment, and international points that span totally different clusters however manifest solely minutely in any particular person cluster are laborious to detect with only a native watchdog. Whereas unfastened coupling permits most service elements to be deployed independently, their deployments might have intricate impacts on one another. For instance, a easy change in an upstream service might probably impression a downstream service if it breaks the contract of API calls between the 2 providers.

These challenges name for automated monitoring, anomaly detection, and rollout impression evaluation options to facilitate deployment choices at velocity.

Gandalf safe deployment – including pre-qualification test, safe deployment policy, local watchdog, and “Gandalf” the global and intelligent watchdog.

Determine 1: Gandalf protected deployment

Gandalf protected deployment service: An AIOps answer

Rising to the problem described above, the Azure Compute Insights staff developed the “Gandalf” protected deployment service—an end-to-end, steady monitoring system for protected deployment. We take into account this a part of the Gandalf AIOps answer suite, which features a few different clever monitoring providers. The code title Gandalf was impressed by the protagonist from The Lord of the Rings, as proven in Determine 1, it serves as a world watchdog, which makes clever deployment choices primarily based on alerts collected. It really works in tandem with native watchdogs, protected deployment insurance policies, and pre-qualification checks, all to make sure deployment security and velocity.

As illustrated in Determine 2, the Gandalf system screens wealthy and consultant alerts from Azure, performs anomaly detection and correlation, then derives insights to help deployment resolution making and actions.

Gandalf system overview – showing data sources, the detection/correlation/decision engine, result orchestration, consumers, and the deployment engine.

Determine 2: Gandalf system overview

Information sources

Gandalf screens alerts throughout efficiency, failures, and occasions as described under. It pre-processes the information to construction them round a unified information schema to help downstream information analytics. It additionally leverages a couple of different analytics providers inside Azure for well being alerts, together with our Digital Machine failure categorization service and close to real-time failure attribution processing service. Sign registration with Gandalf is required when any new service elements are onboarded, to make sure full protection.

  • Efficiency information: Gandalf screens efficiency counters, CPU utilization, reminiscence utilization, and extra – all for a high-level view of efficiency and useful resource consumption patterns of hosted providers.
  • Failure alerts: Gandalf screens each the internet hosting surroundings of buyer’s digital machines (information aircraft) and tenant-level providers (management aircraft). For the information aircraft, it screens failure alerts akin to OS crashes, node faults, and reboots to guage the well being of the VM’s internet hosting surroundings.  On the similar time, it screens failure alerts of the management aircraft like API name failures, to guage the well being of tenant-level providers.
  • Replace occasions: Along with telemetry information collected, Gandalf additionally retains its finger on the heart beat of deployment occasions, which report deployment progress and points.

Detection, correlation, and resolution

Gandalf evaluates the impression scope of the deployment—for instance, the variety of impacted nodes, clusters, and prospects—to make a go/no-go resolution utilizing resolution standards which are skilled dynamically. To stability velocity and protection, Gandalf makes use of an structure with each streaming and batch evaluation engines.

Gandalf correlation process (identifying which rollouts are suspicious) and decision process (assessing the customer impacts of the blamed components/failures).

Determine three: Gandalf Anomaly Detection and Correlation Mode

Determine three reveals an outline of the Gandalf Machine Studying (ML) mannequin. It consists of two components—anomaly detection and correlation course of (to establish suspicious deployments) and a call course of (to guage buyer impression).

Anomaly detection and correlation course of

To make sure exact detection, Gandalf derives fault signatures from enter alerts, which can be utilized to uniquely establish the failure. Then, it detects primarily based on the prevalence of the fault signature.

In large-scale cloud techniques like Azure, easy threshold-based detection shouldn’t be sensible each due to the dynamic nature of the techniques and workloads hosted and due to the sheer quantity of fault signatures. Gandalf applies machine studying strategies to estimate baseline settings primarily based on historic information routinely and might adapt the setting by coaching as wanted.

When Gandalf detects an anomaly, it correlates the noticed failure with deployment occasions and evaluates its impression scope. This helps to filter out failures attributable to non-deployment causes akin to random firmware points.

Since a number of system elements are sometimes deployed concurrently, a vote-veto mechanism is used to determine the connection between the faults and the rollout elements. As well as, temporal and spatial correlations are used to establish the elements at fault. Fault age, which measures the time between rollout and detection of fault signature, is taken into account to permit extra concentrate on new rollouts than previous ones since newly noticed faults are much less more likely to be triggered by the previous rollout.

On this means, Gandalf can detect an anomaly that may result in potential regressions within the buyer expertise early within the course of—earlier than it generates widespread buyer impression. For extra element, discuss with our revealed paper “Gandalf: An Clever, end-to-end analytics service for protected deployment in large-scale cloud infrastructure.”

Choice course of

Lastly, Gandalf evaluates the impression scope of the deployment such because the variety of impacted clusters/nodes/prospects, and finally makes a “go/no-go” resolution. It’s value mentioning that Gandalf is designed to permit builders to customise alerts’ weight task primarily based on their expertise. On this means, it will possibly incorporate area information from human consultants to enrich its machine studying options.

Consequence orchestration

To stability velocity and protection, Gandalf makes use of each streaming and batch processing of incoming alerts. Streaming processing consumes information from Azure Information Explorer, a cloud storage answer supporting analytics with quick velocity. Streaming processing is used to course of fault alerts that occur 1 hour earlier than and after every deployment in every node and runs light-weight evaluation algorithms for fast response.

Batch processing consumes information from Cosmos, a Hadoop-like file system that helps extraordinarily giant volumes of knowledge. It’s used to investigate faults over a bigger time window (typically a 30-day interval) with superior algorithms.

Each stream and batch processing are carried out incrementally with five-minute intervals. On the whole, the incoming telemetry alerts of Gandalf are each streamed into Kusto and saved into Cosmos hourly/each day. With the identical information supply, sometimes there might be inconsistent outcomes from the processing pipeline. That is by design since batch processing makes extra knowledgeable choices and covers latent points that the quick/streaming course of can’t detect.

Deployment expertise transformation

The Gandalf system is now nicely built-in into our DevOps workflow inside Azure and has been broadly adopted for deployment well being monitoring throughout your entire fleet. It not solely helps to stop dangerous rollouts as rapidly as attainable however has additionally reworked the engineers’ and launch managers’ expertise in deploying software program adjustments—from on the lookout for scattered proof to utilizing a single supply of fact, from ad-hoc diagnoses to utilizing interactive troubleshooting—and in so doing, most of the engineers who work together with Gandalf have had their opinions on it reworked as nicely, evolving from skeptics to advocates.

In lots of Azure providers, Gandalf has turn into a default baseline for all launch validations, and it’s thrilling to listen to how a lot our on-call engineers belief Gandalf.


On this put up, now we have launched the Gandalf protected deployment service, an clever, end-to-end analytics service for the protected deployment of Azure providers. Via state-of-the-art anomaly detection, particular and temporal correlation, and outcome orchestration, the Gandalf protected deployment service permits DevOps engineers to make go/no-go choices precisely, and with the speed wanted by hyper-scale cloud platforms like Azure.

We’ll proceed to put money into making use of AI- and machine learning-based applied sciences to enhance cloud service administration, finally to proceed enhancing the client expertise. Search for us to share extra about our AIOps options, together with pre-production analytics to additional assist us push high quality to the left.


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