Configuring Load Balancers
Overview
Configure load balancers across AWS (ALB, NLB), GCP (HTTP(S) LB, TCP/UDP LB), Nginx, and HAProxy. Generate production-ready configurations with health checks, SSL/TLS termination, path-based and host-based routing, sticky sessions, rate limiting, and traffic distribution rules for high-availability deployments.
Prerequisites
- Backend servers identified with IPs, DNS names, and ports
- Load balancer type determined: L4 (NLB, HAProxy TCP) or L7 (ALB, Nginx, HAProxy HTTP)
- SSL/TLS certificates available (ACM, Let's Encrypt, or self-signed) if using HTTPS
- Health check endpoints defined on backend services (e.g.,
/health returning 200)
- Cloud provider CLI installed for managed load balancers (
aws, gcloud)
Instructions
- Select load balancer type based on requirements: ALB for HTTP/HTTPS with path routing, NLB for TCP/UDP with static IPs, Nginx for on-prem reverse proxy, HAProxy for high-performance TCP/HTTP
- Define the backend pool: list all backend server addresses, ports, and weights for weighted distribution
- Configure health checks with appropriate interval (10-30s), timeout (5s), healthy threshold (3), and unhealthy threshold (2)
- Set up SSL/TLS termination: configure certificates, redirect HTTP to HTTPS, set minimum TLS version to 1.2
- Define routing rules: path-based routing (
/api -> API pool, /static -> CDN), host-based routing (api.example.com -> API)
- Enable session persistence (sticky sessions) using cookies or source IP affinity where needed for stateful applications
- Add connection draining to gracefully handle backend removal during deployments
- Configure logging and monitoring: access logs to S3/CloudWatch, request metrics, error rate dashboards
- Test the configuration: validate syntax (
nginx -t, HAProxy config check), verify traffic distribution, and confirm failover behavior
Output
- Nginx configuration files (
nginx.conf, site configs) with upstream blocks and server directives
- HAProxy configuration (
haproxy.cfg) with frontend/backend sections
- Terraform HCL for AWS ALB/NLB with target groups, listeners, and rules
- GCP load balancer Terraform with backend services, URL maps, and health checks
- SSL certificate configuration and renewal automation
Error Handling
| Error |
Cause |
Solution |
502 Bad Gateway |
Backend server unreachable or not responding |
Verify backend IPs, ports, and firewall rules; check backend service health |
SSL certificate verify failed |
Certificate expired, wrong chain, or key mismatch |
Verify certificate validity and chain with openssl s_client; regenerate if needed |
Target is unhealthy |
Health check endpoint returning non-200 or timing out |
Verify health check path returns 200; increase timeout if backend is slow to respond |
nginx: configuration file test failed |
Syntax error in Nginx configuration |
Run nginx -t to identify the specific error line; fix syntax and test again |
Session persistence not working |
Cookie-based stickiness misconfigured or client not sending cookies |
Verify cookie name matches; use IP-based affinity as fallback for non-browser clients |
Examples
- "Configure an AWS ALB with HTTPS listener, path-based routing to two target groups (/api and /web), and health checks on /health."
- "Generate an Nginx reverse proxy config with upstream servers, sticky sessions via cookie, and rate limiting at 100 req/s per IP."
- "Create a HAProxy configuration for TCP load balancing across 4 database read replicas with health checks and connection draining."
Resources
Source: jeremylongshore/claude-code-plugins-plus-skills → skills/.curated/configuring-load-balancers/SKILL.md
Also appears in: jeremylongshore/claude-code-plugins-plus-skills/plugins/devops/load-balancer-configurator/skills/configuring-load-balancers/SKILL.md
1---2name: configuring-load-balancers3description: 'Configure use when configuring load balancers including ALB, NLB, Nginx, and HAProxy. Trigger with phrases like "configure load balancer", "create ALB", "setup nginx load balancing", or "haproxy configuration". Generates production-ready configurations with health checks, SSL termination, sticky sessions, and traffic distribution rules. '4---56# Configuring Load Balancers78## Overview910Configure load balancers across AWS (ALB, NLB), GCP (HTTP(S) LB, TCP/UDP LB), Nginx, and HAProxy. Generate production-ready configurations with health checks, SSL/TLS termination, path-based and host-based routing, sticky sessions, rate limiting, and traffic distribution rules for high-availability deployments.1112## Prerequisites1314- Backend servers identified with IPs, DNS names, and ports15- Load balancer type determined: L4 (NLB, HAProxy TCP) or L7 (ALB, Nginx, HAProxy HTTP)16- SSL/TLS certificates available (ACM, Let's Encrypt, or self-signed) if using HTTPS17- Health check endpoints defined on backend services (e.g., `/health` returning 200)18- Cloud provider CLI installed for managed load balancers (`aws`, `gcloud`)1920## Instructions21221. Select load balancer type based on requirements: ALB for HTTP/HTTPS with path routing, NLB for TCP/UDP with static IPs, Nginx for on-prem reverse proxy, HAProxy for high-performance TCP/HTTP232. Define the backend pool: list all backend server addresses, ports, and weights for weighted distribution243. Configure health checks with appropriate interval (10-30s), timeout (5s), healthy threshold (3), and unhealthy threshold (2)254. Set up SSL/TLS termination: configure certificates, redirect HTTP to HTTPS, set minimum TLS version to 1.2265. Define routing rules: path-based routing (`/api` -> API pool, `/static` -> CDN), host-based routing (`api.example.com` -> API)276. Enable session persistence (sticky sessions) using cookies or source IP affinity where needed for stateful applications287. Add connection draining to gracefully handle backend removal during deployments298. Configure logging and monitoring: access logs to S3/CloudWatch, request metrics, error rate dashboards309. Test the configuration: validate syntax (`nginx -t`, HAProxy config check), verify traffic distribution, and confirm failover behavior3132## Output3334- Nginx configuration files (`nginx.conf`, site configs) with upstream blocks and server directives35- HAProxy configuration (`haproxy.cfg`) with frontend/backend sections36- Terraform HCL for AWS ALB/NLB with target groups, listeners, and rules37- GCP load balancer Terraform with backend services, URL maps, and health checks38- SSL certificate configuration and renewal automation3940## Error Handling4142| Error | Cause | Solution |43|-------|-------|---------|44| `502 Bad Gateway` | Backend server unreachable or not responding | Verify backend IPs, ports, and firewall rules; check backend service health |45| `SSL certificate verify failed` | Certificate expired, wrong chain, or key mismatch | Verify certificate validity and chain with `openssl s_client`; regenerate if needed |46| `Target is unhealthy` | Health check endpoint returning non-200 or timing out | Verify health check path returns 200; increase timeout if backend is slow to respond |47| `nginx: configuration file test failed` | Syntax error in Nginx configuration | Run `nginx -t` to identify the specific error line; fix syntax and test again |48| `Session persistence not working` | Cookie-based stickiness misconfigured or client not sending cookies | Verify cookie name matches; use IP-based affinity as fallback for non-browser clients |4950## Examples5152- "Configure an AWS ALB with HTTPS listener, path-based routing to two target groups (/api and /web), and health checks on /health."53- "Generate an Nginx reverse proxy config with upstream servers, sticky sessions via cookie, and rate limiting at 100 req/s per IP."54- "Create a HAProxy configuration for TCP load balancing across 4 database read replicas with health checks and connection draining."5556## Resources5758- Nginx load balancing: https://nginx.org/en/docs/http/load_balancing.html59- HAProxy configuration: https://www.haproxy.org/download/2.8/doc/configuration.txt60- AWS ALB: https://docs.aws.amazon.com/elasticloadbalancing/latest/application/61- GCP Load Balancing: https://cloud.google.com/load-balancing/docs62- See `${CLAUDE_SKILL_DIR}/references/errors.md` for additional error handling patterns6364---6566**Source:** [`jeremylongshore/claude-code-plugins-plus-skills`](https://github.com/jeremylongshore/claude-code-plugins-plus-skills) → `skills/.curated/configuring-load-balancers/SKILL.md`6768**Also appears in:** `jeremylongshore/claude-code-plugins-plus-skills/plugins/devops/load-balancer-configurator/skills/configuring-load-balancers/SKILL.md`
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