Docker Swarm Resource Configuration#

Dokploy exposes four Docker Swarm resource knobs for each service — Memory Limit, Memory Reservation, CPU Limit, and CPU Reservation — through a shared UI component and a server-side conversion function. Understanding the raw numeric format these fields require is critical, because the documented units (MB/GB, CPU cores) differ from what is actually stored and sent to the Docker API.

Data Model#

All four fields are stored as nullable text strings in the database and validated as z.string().optional() in the tRPC layer 1 2. They appear on every deployable service type: application, postgres, mysql, mariadb, mongo, redis, and libsql.

The Format Mismatch#

Caution: Despite UI tooltips describing values in human-readable terms ("1GB", "2 CPUs"), what is stored in the database and passed to Docker is always a raw integer string.

• Memory: stored as bytes. 1 GB = "1073741824", 256 MB = "268435456" 3.
• CPU: stored as NanoCPUs (10⁻⁹ of a CPU). 2 CPUs = "2000000000", 1 CPU = "1000000000" 4.

The docs page at Advanced settings describes values in user-friendly units, but the underlying API and database deal exclusively with these raw integers.

UI Component: ShowResources#

ShowResources (apps/dokploy/components/dashboard/application/advanced/show-resources.tsx) renders the Resources card for all service types. It is parameterized by { id, type } and uses a queryMap/mutationMap pattern to dispatch the correct tRPC query and mutation for each service type 5.

Each field uses the NumberInputWithSteps component (apps/dokploy/components/ui/number-input.tsx), which provides +/- step buttons and a live human-readable display beneath the raw input:

• Memory fields: step = 256 MB increments; memoryConverter uses multiplier 1024 * 1024 (bytes → MB) and displays as MB or GB 6.
• CPU fields: step = 0.25 CPU increments; cpuConverter uses multiplier 1_000_000_000 (nanosecond-CPUs → CPUs) and displays as N CPU 7.

The createConverter factory bridges raw strings (stored in DB) ↔ numeric values (used in UI math) ↔ formatted display strings (shown to users):

• toValue(raw): parseInt(raw) / multiplier
• fromValue(value): String(Math.round(value * multiplier)) — this is what gets saved.
• formatDisplay(value): formats for display only, never persisted.

Users can also type the raw integer directly into the input field, which is the only input method when not using the step buttons 8.

After saving, users must Redeploy the service for changes to take effect 9.

Server-Side Conversion: calculateResources#

calculateResources (packages/server/src/utils/docker/utils.ts) converts the string fields into the ResourceRequirements object that Dockerode passes to docker service create/update:

MemoryBytes = parseInt(memoryLimit)
NanoCPUs = parseInt(cpuLimit)

It simply calls Number.parseInt() on each non-null string — no unit conversion happens here 10. This is why the values must already be in the correct raw units before reaching this function.

calculateResources is called inside mechanizeDockerContainer in packages/server/src/utils/builders/index.ts, which assembles the full service spec before calling docker.createService() or service.update().

Quick Reference: Common Values#

Key Source Files#