Source

This page is generated from skills/eks-upgrade-check/SKILL.md. Edit the source, not this page.

Vendored skill

This skill is sourced from eks-upgrade-check, also maintained by the APEX team.

EKS Upgrade Readiness Skill

Overview

This skill assesses your live EKS cluster's readiness for a Kubernetes version upgrade. It connects to your cluster via AWS CLI and kubectl, runs automated checks across 8 assessment areas, calculates a readiness score (0-100%), and produces a detailed report with prioritized remediation steps and pre-filled AWS CLI commands.

This skill is laser-focused on upgrade safety — answering the question: "Is it safe to upgrade this cluster to the next version?"

What Gets Assessed

#	Section	Key Checks
01	Version Validation	Upgrade path validity, version skew policy, support status
02	Breaking Changes	Version-specific API removals, behavioral changes, resource impact
03	Deprecated API Detection	Live scan of cluster resources for deprecated/removed APIs
04	Add-on Compatibility	Core add-on versions, OSS add-on matrix, Karpenter compatibility
05	Node Readiness	Node version skew, AL2→AL2023 migration, AMI compatibility
06	Workload Risks	Single replicas, missing PDBs, health probes, resource requests
07	AWS Upgrade Insights	Official EKS pre-upgrade checks and recommendations
08	Upgrade Plan	Pre-filled CLI commands, step-by-step upgrade sequence

Readiness Score

The skill calculates a weighted readiness score:

Category	Max Deduction	Rationale
Breaking Changes	25 pts	Highest risk — can break apps
Deprecated APIs	20 pts	Actionable, fixable pre-upgrade
Node Readiness (skew + subnet IPs)	20 pts	Can block upgrade entirely
Unsupported Version	15 pts	No security patches, urgent upgrade needed
Add-on Compatibility	15 pts	Critical > optional add-ons
Karpenter	10 pts	Only if installed
Workload Risks	10 pts	Best-practice, not blockers
AWS Upgrade Insights	10 pts	Official AWS checks
AL2 Nodes / Behavioral	10 pts	Informational

Hard Blocker Override: If any hard blocker is detected (e.g., incompatible Karpenter, critical add-on DEGRADED, subnet IPs < 5, cluster not ACTIVE), the score is capped at ≤ 59% (NOT READY) regardless of other findings. See references/report-generation.md for the full list.

Score Interpretation:

• 90-100: READY — Safe to proceed
• 80-89: GOOD — Minor issues, can proceed with caution
• 70-79: FAIR — Several issues need attention first
• 60-69: RISKY — Significant issues, not recommended yet
• 0-59: NOT READY — Critical blockers, must resolve first

Prerequisites

1. AWS credentials configured — aws configure or ~/.aws/credentials with EKS access
2. kubectl access to the target cluster (for Kubernetes API queries)
3. Required AWS Permissions:
   • eks:DescribeCluster, eks:ListClusters, eks:ListNodegroups, eks:DescribeNodegroup
   • eks:ListAddons, eks:DescribeAddon, eks:ListInsights, eks:DescribeInsight
   • ec2:DescribeSubnets
   • iam:GetRole, iam:ListAttachedRolePolicies, iam:ListRolePolicies, iam:GetRolePolicy

MCP Server Setup

This skill works without any MCP server — it falls back to AWS CLI and kubectl commands. That fallback path is the default in apex.

For richer EKS operations (live cluster reads, upgrade insights, K8s resource introspection), enable the EKS MCP server via the apex eks-mcp-server skill — it walks you through both AWS-hosted and self-hosted setup options. Once configured, this skill will prefer MCP tools over CLI for EKS operations.

Note: Apex does NOT ship a project-root .mcp.json. MCP setup is opt-in and user-driven through the eks-mcp-server skill.

Configuration

The skill uses your existing AWS credentials. No additional configuration needed if aws eks list-clusters works from your terminal.

To use a specific profile or region, set environment variables:

export AWS_PROFILE=your-profile-name
export AWS_REGION=your-region

Getting Started

Invoke the skill: /eks-upgrade-check

Or simply ask: "Run an EKS upgrade readiness assessment"

The skill will discover your clusters, ask which one to assess and what target version, then run the full assessment.

---

Assessment Workflow

Step 0: Pre-flight

Action 1 — List clusters (test connectivity & discover clusters)

Run aws eks list-clusters to discover available clusters.

• ✅ Success → Show the cluster list. Ask which cluster to assess. If only one cluster, confirm it.
• ❌ Failure → STOP. Do NOT retry more than once. Show:

Cannot access EKS clusters. Try these steps:

1. Check that AWS credentials are configured: aws sts get-caller-identity
2. Check your region: aws eks list-clusters --region <region>
3. Check that MCP servers are enabled in Claude Code

Wait for the user to resolve the issue.

Action 2 — Describe the selected cluster

Run aws eks describe-cluster --name <cluster> and show: cluster name, Kubernetes version, platform version, region, status, account ID.

Action 2b — Validate cluster status

Check the status field from the cluster description. If status is NOT ACTIVE:

• CREATING/UPDATING/DELETING → STOP. Show: "Cluster is currently in <status> state. The EKS API will reject an upgrade request. Wait for the operation to complete, then re-run this assessment."
• FAILED → STOP. Show: "Cluster is in FAILED state. This is a hard blocker — the cluster must be recovered before an upgrade can be attempted. Contact AWS Support if the cluster is stuck in FAILED."

Do NOT proceed with the assessment if cluster status is not ACTIVE. This is a hard blocker (see report-generation.md).

Action 3 — Validate permissions

After describing the cluster, verify key permissions by attempting:

1. aws eks list-nodegroups --cluster-name <cluster>
2. aws eks list-addons --cluster-name <cluster>
3. aws eks list-insights --cluster-name <cluster>

If any fail with AccessDenied, show the user exactly which permission is missing and list the required IAM actions. Do NOT proceed until permissions are confirmed.

Action 4 — Determine target version

Ask: "Your cluster is on v[current]. The next version is v[current+1]. Shall I assess upgrade readiness to v[current+1]?"

If the user specifies a version more than 1 minor version ahead, explain that EKS requires one-version-at-a-time upgrades and show the required path (e.g., 1.29 → 1.30 → 1.31 → 1.32). Offer to assess the first hop.

Action 5 — Confirm and proceed

Steps 1-8: Run Assessment

Read each steering file in order from ${CLAUDE_SKILL_DIR}/references/. For each section:

1. Read the steering file
2. Execute the checks described in it using AWS CLI and kubectl commands
3. Collect findings with severity ratings

Steering file loading guide:

User Request	Steering File(s)
Full upgrade assessment	ALL files in order
Version / upgrade path	references/version-validation.md
Breaking changes / API removals	references/breaking-changes.md
Deprecated APIs	references/deprecated-apis.md
Add-on compatibility / Karpenter	references/addon-compatibility.md
Node readiness / AL2 / AMI	references/node-readiness.md
Workload risks / PDB / probes	references/workload-risks.md
AWS Insights	references/upgrade-insights.md
Generate report	references/report-generation.md

Step 9: Calculate Score & Generate Report

Read ${CLAUDE_SKILL_DIR}/references/report-generation.md and produce the report.

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Tool Usage Rules

1. Do NOT call any tools when this skill is first activated. Wait for the user to ask.
2. Do NOT hardcode or guess cluster names. Always discover by listing first.
3. Do NOT retry a failed command more than once.
4. Always read the relevant steering file before executing checks for that section.
5. Use aws CLI and kubectl for cluster queries. If MCP servers are available, prefer them for EKS operations.

Data Files

• OSS Add-on Registry: ${CLAUDE_SKILL_DIR}/data/oss_addon_registry.json — identifiers and authoritative upstream URLs for common OSS add-ons. This file does NOT contain compatibility data. Compatibility is always verified live via the registry's compatibility_url and releases_url fields. If an add-on is not in the registry or the upstream source is unreachable, report UNKNOWN — never guess.
• HTML Converter: ${CLAUDE_SKILL_DIR}/tools/md_to_html.py — converts markdown reports to HTML

Report Output

• Markdown: EKS-Upgrade-Assessment-<cluster>-<version>-<YYYY-MM-DD>-<HHMM>.md
• HTML: Run python3 ${CLAUDE_SKILL_DIR}/tools/md_to_html.py <report>.md to convert

Do NOT generate HTML manually. Always use the conversion script.