apache/flink · error · IllegalArgumentException

The cpu cores should be positive.

Error message

The cpu cores should be positive.

What it means

SlotSharingGroup.Builder.setPassword-style validation: setCpuCores(double) rejects values <= 0 with this IllegalArgumentException, because a slot sharing group's resource spec must declare a strictly positive CPU share. Zero or negative cores would make the group unschedulable, so the builder fails fast.

Source

Thrown at flink-core-api/src/main/java/org/apache/flink/api/common/SlotSharingGroup.java:155

    /** Builder for {@link SlotSharingGroup}. */
    @Experimental
    public static class Builder {
        private final String name;
        private Double cpuCores;
        private MemorySize taskHeapMemory;
        private MemorySize taskOffHeapMemory;
        private MemorySize managedMemory;
        private final Map<String, Double> externalResources = new HashMap<>();

        private Builder(String name) {
            this.name = name;
        }

        /** Set the CPU cores for this SlotSharingGroup. */
        public Builder setCpuCores(double cpuCores) {
            if (cpuCores <= 0) {
                throw new IllegalArgumentException("The cpu cores should be positive.");
            }
            this.cpuCores = cpuCores;
            return this;
        }

        /** Set the task heap memory for this SlotSharingGroup. */
        public Builder setTaskHeapMemory(MemorySize taskHeapMemory) {
            if (taskHeapMemory.compareTo(MemorySize.ZERO) <= 0) {
                throw new IllegalArgumentException("The task heap memory should be positive.");
            }
            this.taskHeapMemory = taskHeapMemory;
            return this;
        }

        /** Set the task heap memory for this SlotSharingGroup in MB. */
        public Builder setTaskHeapMemoryMB(int taskHeapMemoryMB) {
            if (taskHeapMemoryMB <= 0) {
                throw new IllegalArgumentException("The task heap memory should be positive.");

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Set a positive value, e.g. setCpuCores(1.0) or a fraction like 0.5.
2. Validate derived values before building: if the computed cores are <= 0, fall back to a documented default.
3. Check the option's docs for minimum supported values.

Example fix

// before
.newBuilder("group").setCpuCores(totalCores - reservedCores) // 0.0 when fully reserved

// after
.newBuilder("group").setCpuCores(Math.max(totalCores - reservedCores, 0.1))

if (!(cpuCores > 0)) throw new IllegalArgumentException("cpuCores must be > 0, got " + cpuCores);
SlotSharingGroup.newBuilder(name).setCpuCores(cpuCores);

When it happens

Trigger: Calling SlotSharingGroup.newBuilder(name).setCpuCores(0), setCpuCores(-1), or passing a computed value (e.g. totalCores - reserved) that evaluates to 0 or negative.

Common situations: Deriving cpuCores from environment variables or fractions of TaskManager slots that round to zero; configuration templates defaulting to 0 meaning 'unset'; arithmetic that subtracts too much.

Related errors

• The cpu cores and task heap memory are required when specify
• At least one trigger condition must be configured.
• The task heap memory should be positive.
• The jarFile and entryPointClassName can not be null at the s
• Not allowed configuration change(s) were detected:\n - {erro

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/be7dbb6b00a8a56f. Report an issue: GitHub.