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Cloud · head to head

Azure Functions vs Linkerd

Azure Functions logo

Azure Functions

Cloud

Event-driven serverless compute on Azure

From
Free
Rated
-
Full reviewWebsite
Linkerd logo

Linkerd

Cloud

Lightweight service mesh for Kubernetes

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Azure Functions consumption plan free grant is capped at 1 million executions and 400,000 GB-seconds of resource consumption per month per subscription, billed per GB-second beyond that; Linkerd deliberately fewer features than Istio, so complex routing and multi-cluster policy can hit its limits

Where they differ

Only the attributes on which Azure Functions and Linkerd actually diverge.

Attributes where Azure Functions and Linkerd differ
AttributeAzure FunctionsLinkerd
Pricing modelusage-basedOpen source, no licence fee
PlatformsWebKubernetes, Linux

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Cloud).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Azure Functions

Nothing recorded that Linkerd does not also cover.

Only in Linkerd

  • Automatic mutual TLS
  • Golden metrics
  • Rust micro-proxy
  • Traffic policy

What people use each for

The jobs each tool is most often brought in to do.

Azure Functions

  • Event-driven computingnot Linkerd
  • Serverless application backendnot Linkerd
  • Scalable API endpointsnot Linkerd

Linkerd

  • Adding mutual TLS between services to satisfy a compliance requirementnot Azure Functions
  • Getting per-service latency and success rates without instrumenting applicationsnot Azure Functions
  • Progressive delivery with traffic splitting during rolloutsnot Azure Functions

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Azure Functions

  • Consumption plan free grant is capped at 1 million executions and 400,000 GB-seconds of resource consumption per month per subscription, billed per GB-second beyond that
  • The newer Flex Consumption plan's free grant is smaller still, at 250,000 executions and 100,000 GB-seconds per month
  • Premium plan avoids per-execution charges but bills continuously for allocated core seconds and memory regardless of invocation volume
  • Memory is rounded up to the nearest 128 MB and execution time to the nearest 1 ms for billing, so small overages round upward

Linkerd

  • Deliberately fewer features than Istio, so complex routing and multi-cluster policy can hit its limits
  • Kubernetes only, with no story for workloads outside a cluster
  • A sidecar per pod is still real memory and latency overhead, however small, and a mesh is another layer to debug during incidents

Pricing, plan by plan

Azure Functions

Free
  • Consumption Plan$null/month
    • 1 million requests free monthly
    • 400,000 GB-seconds free monthly
    • Billed per second and executions
  • Flex Consumption Plan$null/month
    • 250,000 executions free monthly
    • 100,000 GB-seconds free monthly
    • Event-driven scaling
  • Premium Plan$null/month
    • No execution charges
    • At least one instance required
    • Includes automatic scaling and VNET access

Linkerd

Free
  • LinkerdFree
    • Full functionality
    • No usage limits
    • Community support

Which should you pick?

Choose Azure Functions if

  • You want to start without paying.
Azure Functions review

Choose Linkerd if

  • You need automatic mutual tls.
  • You want to start without paying.
  • You work on Kubernetes, Linux.
  • You also want golden metrics.
Linkerd review

Questions people ask

Is Azure Functions or Linkerd better?
Neither clearly leads. Azure Functions starts at Free and Linkerd at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Azure Functions or Linkerd?
Azure Functions starts at Free and Linkerd at Free.
Does Azure Functions or Linkerd run on more platforms?
Azure Functions runs on Web. Linkerd runs on Kubernetes, Linux.
Can I use Azure Functions for free?
Both have a free tier, so you can try either at no cost before committing.
What is Azure Functions best used for?
Azure Functions is most often used for event-driven computing, serverless application backend, scalable api endpoints. Of those, event-driven computing and serverless application backend are not what Linkerd is typically brought in for.
What can Azure Functions do that Linkerd cannot?
Linkerd covers Automatic mutual TLS, Golden metrics, Rust micro-proxy, Traffic policy.

Answered from the vendors’ own pages

Azure Functions: Does Azure Functions have a free tier?

Yes, Azure Functions includes a monthly free grant of 1 million requests and 400,000 GB-seconds on the Consumption Plan, or 250,000 executions and 100,000 GB-seconds on Flex Consumption.

Source
Linkerd: Is Linkerd free?

The open-source project is free. Buoyant, its maintainer, sells enterprise distributions and support separately.

Azure Functions: What is Azure Functions' pricing model?

Azure Functions uses usage-based pricing. Consumption plans charge per second of resource consumption and per execution, measured in gigabyte-seconds and rounded to the nearest 128 MB.

Source
Linkerd: Linkerd or Istio?

Linkerd trades features for simplicity, with a smaller proxy and far less configuration. Istio is more capable and correspondingly more work to run.

Azure Functions: What is the minimum execution time for Azure Functions?

The minimum execution time is 100 milliseconds on Consumption plans. Premium plans charge based on core seconds and allocated memory.

Source
Linkerd: Do I need a service mesh at all?

Only if you need mutual TLS, uniform retries or per-service traffic metrics across many services. For a handful of services it is usually more machinery than the problem justifies.

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