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Software · head to head

Fluent Bit vs Azure Monitor

Fluent Bit logo

Fluent Bit

Software

Fast and Lightweight Log Processor

From
Free
Rated
-
Full reviewWebsite
Azure Monitor logo

Azure Monitor

Software

Azure's Monitoring and Diagnostics Service

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Fluent Bit fluent Bit ships over 100 built in plugins against more than 1,000 external plugins available for Fluentd, so fewer integrations exist out of the box; Azure Monitor billed per GB ingested across three separate log plans, Auxiliary, Basic and Analytics, so the plan chosen changes the rate as much as the volume does
  • They diverge on capability: Fluent Bit covers Lightweight processing, Azure Monitor covers Metrics collection.

Where they differ

Only the attributes on which Fluent Bit and Azure Monitor actually diverge.

Attributes where Fluent Bit and Azure Monitor differ
AttributeFluent BitAzure Monitor
Pricing modelopen-sourceusage-based
Founded20152010

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

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 Fluent Bit

  • Lightweight processing
  • Data parsing
  • Event filtering

Only in Azure Monitor

  • Metrics collection
  • Alerts and notifications
  • Custom dashboards

Both cover

  • Log collection
  • API
  • Webhooks
  • REST
  • Web support
  • Api support

What people use each for

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

Fluent Bit

  • Lightweight log and metric forwarding from containers and edge devicesnot Azure Monitor
  • Kubernetes node level log collection with a small memory footprintnot Azure Monitor
  • Filtering and enriching telemetry before shipping it to a backendnot Azure Monitor

Azure Monitor

  • Collecting logs and metrics from Azure resourcesnot Fluent Bit
  • Alerting on metric thresholds and log queriesnot Fluent Bit
  • Application performance monitoring through Application Insightsnot Fluent Bit
  • Long-term log retention for compliancenot Fluent Bit
  • Querying operational data with KQLnot Fluent Bit

Where each one falls short

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

Fluent Bit

  • Fluent Bit ships over 100 built in plugins against more than 1,000 external plugins available for Fluentd, so fewer integrations exist out of the box
  • It is written in C, so extending it beyond the built in plugins means writing C rather than Ruby
  • Dependencies are zero only until a plugin requires one

Azure Monitor

  • Billed per GB ingested across three separate log plans, Auxiliary, Basic and Analytics, so the plan chosen changes the rate as much as the volume does
  • Only the first 5 GB a month of Analytics logs is free per billing account
  • Retention beyond the base period is charged per GB per month, up to 2 years interactive and 12 years long term
  • Log queries and search jobs are billed per GB scanned, so investigating an incident costs money
  • Alert rules are billed per time series for metrics and by execution frequency for logs
  • The pricing page shows placeholders rather than rates until a region and currency are chosen

Pricing, plan by plan

Fluent Bit

Free
  • FreeFree
    • Log collection
    • Lightweight processing
    • Data parsing

Azure Monitor

Free
  • FreeFree
    • Log collection
    • Metrics collection
    • Alerts and notifications

Which should you pick?

Choose Fluent Bit if

  • You need lightweight processing.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want data parsing.
Fluent Bit review

Choose Azure Monitor if

  • You need metrics collection.
  • You want to start without paying.
  • You work on Web, Api.
  • You also want alerts and notifications.
Azure Monitor review

Questions people ask

Is Fluent Bit or Azure Monitor better?
Neither clearly leads. Fluent Bit starts at Free and Azure Monitor at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Fluent Bit or Azure Monitor?
Fluent Bit starts at Free and Azure Monitor at Free.
Does Fluent Bit or Azure Monitor run on more platforms?
Both run on Web, Api, so platform support will not decide this one for you.
Can I use Fluent Bit for free?
Both have a free tier, so you can try either at no cost before committing.
What is Fluent Bit best used for?
Fluent Bit is most often used for lightweight log and metric forwarding from containers and edge devices, kubernetes node level log collection with a small memory footprint, filtering and enriching telemetry before shipping it to a backend. Of those, lightweight log and metric forwarding from containers and edge devices and kubernetes node level log collection with a small memory footprint are not what Azure Monitor is typically brought in for.
What can Fluent Bit do that Azure Monitor cannot?
Fluent Bit covers Lightweight processing, Data parsing, Event filtering. Azure Monitor covers Metrics collection, Alerts and notifications, Custom dashboards. Both handle Log collection, API, Webhooks, REST.
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