AWS Batch

AWS Batch Skill

Analyze AWS Batch compute environments and jobs with parallel execution and anti-hallucination guardrails.

Relationship to other AWS skills:

• aws-batch/ → Batch-specific analysis (compute environments, job queues, jobs)
• aws/ → "How to execute" (parallel patterns, throttling, output format)

CRITICAL: Parallel Execution Requirement

ALL independent operations MUST run in parallel using background jobs (&) and wait.

#!/bin/bash
export AWS_PAGER=""

for ce in $compute_envs; do
  describe_compute_env "$ce" &
done
wait

Helper Functions

#!/bin/bash
export AWS_PAGER=""

# List compute environments
list_compute_environments() {
  aws batch describe-compute-environments \
    --output text \
    --query 'computeEnvironments[].[computeEnvironmentName,state,status,type,computeResources.type,computeResources.minvCpus,computeResources.maxvCpus,computeResources.desiredvCpus]'
}

# List job queues
list_job_queues() {
  aws batch describe-job-queues \
    --output text \
    --query 'jobQueues[].[jobQueueName,state,status,priority,computeEnvironmentOrder[].computeEnvironment]'
}

# List jobs by status
list_jobs() {
  local queue=$1 status=$2
  aws batch list-jobs --job-queue "$queue" --job-status "$status" \
    --output text \
    --query 'jobSummaryList[].[jobId,jobName,status,createdAt,startedAt,stoppedAt,statusReason]' | head -20
}

# Describe jobs (batch)
describe_jobs() {
  local job_ids="$@"
  aws batch describe-jobs --jobs $job_ids \
    --output text \
    --query 'jobs[].[jobId,jobName,status,statusReason,container.exitCode,container.reason,startedAt,stoppedAt]'
}

# List job definitions
list_job_definitions() {
  aws batch describe-job-definitions --status ACTIVE \
    --output text \
    --query 'jobDefinitions[].[jobDefinitionName,revision,type,status,containerProperties.vcpus,containerProperties.memory]' | head -20
}

# List scheduling policies
list_scheduling_policies() {
  aws batch list-scheduling-policies \
    --output text \
    --query 'schedulingPolicies[].[arn,name]' 2>/dev/null
}

Common Operations

1. Compute Environment Overview

#!/bin/bash
export AWS_PAGER=""
aws batch describe-compute-environments \
  --output text \
  --query 'computeEnvironments[].[computeEnvironmentName,state,status,type,computeResources.type,computeResources.minvCpus,computeResources.maxvCpus,computeResources.desiredvCpus]'

2. Job Queue Status with Active Jobs

#!/bin/bash
export AWS_PAGER=""
QUEUES=$(aws batch describe-job-queues --output text --query 'jobQueues[].jobQueueName')
for queue in $QUEUES; do
  {
    info=$(aws batch describe-job-queues --job-queues "$queue" \
      --output text --query 'jobQueues[].[jobQueueName,state,priority]')
    running=$(aws batch list-jobs --job-queue "$queue" --job-status RUNNING \
      --output text --query 'length(jobSummaryList)')
    pending=$(aws batch list-jobs --job-queue "$queue" --job-status PENDING \
      --output text --query 'length(jobSummaryList)')
    submitted=$(aws batch list-jobs --job-queue "$queue" --job-status SUBMITTED \
      --output text --query 'length(jobSummaryList)')
    printf "%s\tRunning:%s\tPending:%s\tSubmitted:%s\n" "$info" "$running" "$pending" "$submitted"
  } &
done
wait

3. Failed Job Investigation

#!/bin/bash
export AWS_PAGER=""
QUEUES=$(aws batch describe-job-queues --output text --query 'jobQueues[].jobQueueName')
for queue in $QUEUES; do
  FAILED=$(aws batch list-jobs --job-queue "$queue" --job-status FAILED \
    --output text --query 'jobSummaryList[:5].jobId')
  [ -z "$FAILED" ] && continue
  aws batch describe-jobs --jobs $FAILED \
    --output text \
    --query 'jobs[].[jobName,status,statusReason,container.exitCode,container.reason,stoppedAt]' &
done
wait

4. Array Job Progress

#!/bin/bash
export AWS_PAGER=""
QUEUE=$1
ARRAY_JOBS=$(aws batch list-jobs --job-queue "$QUEUE" --job-status RUNNING \
  --output text --query 'jobSummaryList[?arrayProperties].jobId')
for job_id in $ARRAY_JOBS; do
  aws batch describe-jobs --jobs "$job_id" \
    --output text \
    --query 'jobs[].[jobName,arrayProperties.size,arrayProperties.statusSummary]' &
done
wait

5. Job Definition Audit

#!/bin/bash
export AWS_PAGER=""
aws batch describe-job-definitions --status ACTIVE \
  --output text \
  --query 'jobDefinitions[].[jobDefinitionName,revision,type,platformCapabilities[0],containerProperties.image,containerProperties.vcpus,containerProperties.memory,retryStrategy.attempts]' | head -30

Anti-Hallucination Rules

1. Compute environment types - MANAGED or UNMANAGED. Managed CEs auto-scale. Unmanaged CEs require manual instance management.
2. Compute resource types - EC2, SPOT, FARGATE, or FARGATE_SPOT. Each has different pricing and availability characteristics.
3. Job status flow - SUBMITTED -> PENDING -> RUNNABLE -> STARTING -> RUNNING -> SUCCEEDED/FAILED. Jobs do not skip states.
4. vCPU units - minvCpus, maxvCpus, desiredvCpus are in vCPU units, not instance counts. The scheduler maps vCPUs to instance types.
5. Array job indexing - Array job indices are 0-based. An array of size 100 has indices 0-99. Each index runs as a separate container.

Output Format

Present results as a structured report:

Aws Batch Report
════════════════
Resources discovered: [count]

Resource       Status    Key Metric    Issues
──────────────────────────────────────────────
[name]         [ok/warn] [value]       [findings]

Summary: [total] resources | [ok] healthy | [warn] warnings | [crit] critical
Action Items: [list of prioritized findings]

Target ≤50 lines of output. Use tables for multi-resource comparisons.

Counter-Rationalizations

Common Pitfalls

• PENDING vs RUNNABLE: PENDING means the job is waiting for dependencies. RUNNABLE means it is ready but waiting for compute capacity. Extended RUNNABLE time indicates insufficient capacity.
• Fargate limitations: Fargate Batch jobs have vCPU/memory limits (max 16 vCPU, 120 GB). EC2 CEs support larger instances.
• Spot interruptions: SPOT compute environments may lose instances. Check statusReason for "Host EC2 (instance i-xxx) terminated" messages.
• CloudWatch statistics syntax: Use spaces not commas: --statistics Average Maximum.
• Job definition revisions: Each update creates a new revision. Jobs reference a specific revision. Use :N suffix for specific revision or omit for latest active.