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Cloud · head to head

Azure Functions vs Buildah

Azure Functions logo

Azure Functions

Cloud

Event-driven serverless compute on Azure

From
Free
Rated
-
Full reviewWebsite
Buildah logo

Buildah

Cloud

Build OCI container images without a daemon or a Dockerfile

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; Buildah linux only, with no native macOS or Windows support

Where they differ

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

Attributes where Azure Functions and Buildah differ
AttributeAzure FunctionsBuildah
Pricing modelusage-basedOpen source, no licence fee
PlatformsWebLinux

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 Buildah does not also cover.

Only in Buildah

  • Daemonless builds
  • Rootless
  • Dockerfile compatible
  • Scriptable builds

What people use each for

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

Azure Functions

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

Buildah

  • Building images in CI without a privileged Docker daemonnot Azure Functions
  • Producing minimal images with tighter layer control than a Dockerfile givesnot Azure Functions
  • Scripted image assembly where a Dockerfile is the wrong abstractionnot 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

Buildah

  • Linux only, with no native macOS or Windows support
  • Scriptable builds are powerful but less portable and less familiar than a Dockerfile
  • Narrow by design: it builds images and does not run them, so it needs Podman or another runtime alongside

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

Buildah

Free
  • BuildahFree
    • 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 Buildah if

  • You need daemonless builds.
  • You want to start without paying.
  • You work on Linux.
  • You also want rootless.
Buildah review

Questions people ask

Is Azure Functions or Buildah better?
Neither clearly leads. Azure Functions starts at Free and Buildah at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Azure Functions or Buildah?
Azure Functions starts at Free and Buildah at Free.
Does Azure Functions or Buildah run on more platforms?
Azure Functions runs on Web. Buildah runs on 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 Buildah is typically brought in for.
What can Azure Functions do that Buildah cannot?
Buildah covers Daemonless builds, Rootless, Dockerfile compatible, Scriptable builds.

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
Buildah: Is Buildah free?

Yes, open source with no licence fee.

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
Buildah: Do I still need a Dockerfile?

No. Buildah reads Dockerfiles if you have them, but images can be built entirely from shell commands instead.

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
Buildah: How is Buildah different from Podman?

Buildah builds images; Podman runs them. Podman actually embeds Buildah for its build command, and the two are designed to be used together.

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