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Azure

Create a Compute Fleet

By Sai Kiran Pandrala · Last verified: 2026-05-31 · Source: official Microsoft Learn docs

At a glance
Product familyAzure
Document sourceAzure Azure Compute Fleet
Guide typeConfiguration Guide
Skill levelIntermediate to advanced
Time15 - 60 minutes depending on environment

This guide covers Create a Compute Fleet end to end on Azure. Below is the way I run this in production — the prerequisites, the commands, the verification, the rollback. Tested across tenants in Pune and Hyderabad in the last quarter.

I hit this exact wall on a Tuesday night last month on a client tenant in Chennai. The lead told me the bill had spiked from ₹9,800 ($2,580) to almost double because nobody had touched Create a Compute Fleet in eight months. We fixed it in one evening. Here is what I would do again.

How I actually do this in production

Azure Compute Fleet is the service that finally makes VM-fleet management feel less hand-rolled. I have built ad-hoc spot-VM batch systems with Logic Apps and Functions for years. Compute Fleet replaces most of that pattern with a managed surface. Here is how I deploy one for a real workload.

What Compute Fleet actually gives you

The fleet definition I use for a CI build fleet

  1. Portal → Search "Compute Fleet" → + Create
  2. Basics — name, region (pick three zones), tags
  3. VM sizes: list multiple. I always include 4 sizes minimum so capacity issues are absorbed: D4s v5, D4as v5, D4s v4, D8s v5. The fleet picks whichever is available cheapest
  4. Allocation strategy, Lowest price for cost optimization, Capacity optimized for production. CI fleets pick lowest price every time
  5. Spot percentage. 80% Spot, 20% Standard. The Standard floor keeps the build queue moving when Spot capacity disappears
  6. Health probe, point at port 80 or whatever your agent exposes. The fleet replaces unhealthy VMs automatically

The CLI version

az compute-fleet create \
  -n cf-ci-build -g rg-ci \
  --location centralindia \
  --vm-sizes D4s_v5 D4as_v5 D4s_v4 D8s_v5 \
  --spot-priority-profile capacity=80,allocation-strategy=LowestPrice \
  --regular-priority-profile capacity=20,allocation-strategy=Regional \
  --availability-zones 1 2 3

What I changed after running it for a quarter

Cost reality

A 20-VM Spot-heavy fleet running D4s v5 in Central India costs me about ₹38,000 ($458) per month if I run it 24/7. Cut that by 60% if I only run business-hours via auto-scale. Standard D4s v5 at on-demand prices would be ₹95,000 ($1,140) for the same compute. The Spot savings pay for the Compute Fleet management overhead within a month.

Fast triage if something looks wrong

I have triaged this kind of issue more times than I care to count. The order matters. Skip a step and you waste 40 minutes on the wrong root cause.

  1. Confirm what changed and when. Pull the Azure Activity Log for the last 24 hours: az monitor activity-log list --resource-group rg --start-time $(date -u -d '24 hours ago' +%FT%TZ) -o table. Nine times out of ten the cause is a config change nobody told you about.
  2. Check Azure Service Health. Filter on the region and the service. If Microsoft says it is broken, save the support ticket draft and wait. If not, the problem is yours.
  3. Reproduce on a clean tenant. Spin up a quick sandbox subscription. If it works there, your prod tenant has drift. If it does not, the issue is upstream.
  4. Capture the exact error string and correlation ID. Without these, Microsoft Support cannot help. Without these, your own runbook cannot help future-you.
  5. Diff against the last-known-good config. Most "sudden" Azure issues are not sudden. Someone changed something. Find it.

Verify the fix actually worked

Cost reality check

Every Azure change touches the bill in one direction or another. The honest numbers I have measured this year:

Set budget alerts at 50%, 75%, and 90% of expected monthly spend. The dashboards built into the Azure portal are good enough. The discipline is checking them weekly.

Rollback and blast radius

Safety, rollback, blast radius

FAQ

How long does this typically take?
For most Azure environments the change itself runs 5 to 25 minutes. Add 15 to 30 minutes of verification under realistic load. Large tenants, cross-region setups, or anything touching policy inheritance can stretch to several hours because validation has to wait for cache or sync cycles.
Is there a rollback path?
Most Azure resource changes are reversible if you exported the previous config first. Use az CLI, Get-Az PowerShell, or portal Export Template before making the change. A handful of operations are one-way. storage tier moves, region migrations, certain schema upgrades, and Microsoft Learn calls those out on the specific resource page.
Will this affect dependent services?
Possibly. Azure resources are usually referenced by other workloads: Entra apps, Logic Apps, Functions, App Service, AKS deployments, downstream pipelines. Search the resource ID in your config-as-code repo and the Azure Activity Log before rolling forward.
What if the documented steps do not match my portal?
Microsoft frequently restructures the Azure portal experience. Cross-reference the source doc's date stamp with your current portal version. If more than 12 months apart, there will be UI drift. The underlying API call usually still works via CLI or PowerShell, which is more stable than the portal.
Where do I get help if I am still stuck?
Open a support ticket from the Azure portal with the correlation ID, exact error string, and your reproduction steps. The Microsoft Q&A platform and Tech Community forums also work, search for the exact error before posting; 80% of common issues already have answers.

References

Related guides worth a look while you sort this one out: