ricmmartins/azure-sre-agent-skills/03-capacity-planning

Capacity Planning

Purpose

Analyze current resource utilization, quota consumption, and growth trends to predict capacity risks and recommend scaling actions before limits are hit.

When to use this skill

• User asks "will our infrastructure handle the traffic spike?"
• User asks about quotas, limits, or capacity
• Pre-event planning (Black Friday, product launch, marketing campaign)
• Quarterly capacity review
• After hitting a quota or throttling limit

Pre-check

Confirm with the user:

• Scope: which subscriptions and regions
• Time horizon: when is the expected load increase? (default: 30 days)
• Expected growth factor (e.g., 2x, 5x, 10x current load)
• Critical workloads to prioritize

Assessment procedure

Step 1: Quota utilization

Check current quota usage across all critical resource providers.

az vm list-usage --location <region> -o table
az network list-usages --location <region> -o table
az storage account list --query "length(@)"

Check for:

• vCPU quotas: Total and per-family (Dv5, Ev5, etc.) — flag if > 70% utilized
• Public IPs: Usage vs. limit
• Load balancers: Usage vs. limit
• Network interfaces: Usage vs. limit
• Storage accounts per subscription: Usage vs. 250 limit
• App Service plans per region
• AKS clusters per subscription

Build a quota utilization table. Use Unicode emoji characters directly (🟢🟡🔴) — never use emoji shortcodes like :green_circle: or :red_circle:.

Step 2: Compute capacity

Analyze current compute utilization and headroom.

1. VM utilization (last 14 days):

• Average and P95 CPU across all VMs
• Average and P95 memory (if available via Log Analytics)
• Flag VMs consistently > 80% CPU or memory

1. App Service plan utilization:

``bash az appservice plan list --query "[].{name:name, sku:sku.name, workers:numberOfWorkers, maxWorkers:maximumElasticWorkerCount}" -o table ``

• Current instance count vs. max
• CPU/memory % of the plan
• Autoscale rules and current headroom

1. AKS cluster capacity:

``bash az aks list --query "[].{name:name, nodeCount:agentPoolProfiles[0].count, maxCount:agentPoolProfiles[0].maxCount, vmSize:agentPoolProfiles[0].vmSize}" -o table ``

• Node count vs. max count
• Pod density per node
• Cluster autoscaler configuration

1. Container Apps:

• Current replicas vs. max replicas
• Autoscale rules (HTTP concurrency, CPU, custom)

Step 3: Data layer capacity

1. SQL Database:

• DTU/vCore utilization (avg and P95)
• Storage usage vs. max size
• Connection count vs. limit

1. Cosmos DB:

• RU consumption vs. provisioned (or autoscale max)
• Storage per container
• 429 (throttling) rate from metrics

1. Redis Cache:

• Memory usage %
• Connection count vs. max
• Server load %

1. Storage accounts:

• Ingress/egress patterns
• Transaction rates vs. limits
• Blob count growth rate

Step 4: Networking capacity

1. ExpressRoute / VPN Gateway: Bandwidth utilization %
2. Application Gateway / Front Door: Connection count, throughput
3. NAT Gateway: SNAT port utilization
4. DNS zones: Query volume trends

Step 5: Growth projection

Based on the data collected:

1. Plot utilization trends for the last 90 days
2. Apply linear projection to estimate when each resource hits 80% and 100%
3. If the user specified a growth factor, multiply current usage and check against limits

Build a risk timeline:

Step 6: Quota increase requests

For any quota that needs increasing, generate the correct request command:

# Request a quota increase via the Azure portal Support + Troubleshooting flow,
# or use the REST API directly:
az rest --method patch \
  --url "https://management.azure.com/subscriptions/<sub-id>/providers/Microsoft.Capacity/resourceProviders/Microsoft.Compute/locations/<region>/serviceLimits/StandardDv5Family?api-version=2020-10-25" \
  --body '{"properties":{"limit":{"limitObjectType":"LimitValue","value":<new-limit>}}}'

Note: The az quota CLI extension is in preview and syntax may change. The REST API approach above is stable. Alternatively, guide users to submit quota requests via the Azure portal: Help + support > New support request > Service and subscription limits (quotas).

Step 7: Recommendations

For each risk identified:

1. Immediate: Quota increase requests, SKU upgrades
2. Short-term (1-2 weeks): Autoscale configuration, caching layers
3. Long-term: Architecture changes (sharding, async patterns, CDN)

Accepted exceptions (optional)

If the user provides a list of accepted exceptions, do not flag those items. Instead, note them in the report as Accepted Exception with the reason provided.

Example format the user may provide:

When exceptions are provided:

• Skip the flagged checks in scoring
• List them in a separate "Accepted Exceptions" section at the end of the report
• Recalculate the overall score excluding excepted checks

Expected output

Report header (mandatory — use this exact format)

Capacity Planning Report

Capacity summary

Risk matrix

Table with all resources, current utilization, projected utilization at specified growth factor, and recommended action.

Scaling runbook

Step-by-step actions to prepare for the expected load increase, ordered by priority and dependency.

Remediation guidance

For each capacity risk identified, include in the output:

1. The specific az CLI command to remediate (quota increase, scale-up, autoscale config)
2. Use GetAzCliHelp to validate the command syntax before suggesting
3. The official Microsoft Learn documentation link

References

• Quotas Overview: https://learn.microsoft.com/en-us/azure/quotas/quotas-overview
• VM Sizes: https://learn.microsoft.com/en-us/azure/virtual-machines/sizes/overview
• Autoscale: https://learn.microsoft.com/en-us/azure/azure-monitor/autoscale/autoscale-overview
• App Service Scaling: https://learn.microsoft.com/en-us/azure/app-service/manage-scale-up

Sample output

The following is a redacted example of what the report looks like when run against a subscription.

Capacity Planning Report

Capacity summary

Risk matrix (sample)

Scaling runbook (sample)

Remediation guidance (sample)

# Request vCPU quota increase via REST API
az rest --method patch \
  --url "https://management.azure.com/subscriptions/a1b2c3d4-.../providers/Microsoft.Capacity/resourceProviders/Microsoft.Compute/locations/eastus/serviceLimits/StandardDv5Family?api-version=2020-10-25" \
  --body '{"properties":{"limit":{"limitObjectType":"LimitValue","value":200}}}'
 
# Scale up SQL Database
az sql db update --resource-group rg-data-prod --server sql-contoso-prod --name appdb --service-objective S4