You ship code. Your users hate downtime. And if your app speaks TCP or UDP, you probably hacked rollouts with scripts, maintenance windows, and crossed fingers.
That changes now. Amazon ECS just added native support for NLB canary and linear deployments. Translation: you can slowly shift real traffic, connections and all, without duct tape. That means smaller blast radius, faster rollbacks, and fewer 3 a.m. texts asking if prod is down.
Here’s the kicker: NLB is built to scale. AWS says it can handle millions of requests each second with ultra-low latency. Pair that with ECS traffic shifting, and gaming servers, IoT backends, and trading gateways finally get sane, safe deploys.
If you’ve been googling amazon ecs network load balancer tutorial, this is your field guide. What changed, why it matters, and how to run your first canary without bricking long-lived sessions.
If you’ve dealt with sticky sessions, static IP needs, or strict allowlists, you get it. NLB gives you raw TCP or UDP power, keeps source IPs, and plays nice with TLS. Now ECS can shift traffic natively, so you get L4 speed with canary and linear guardrails.
Think of this as the missing playbook for real-time stuff. We’ll compare NLB and ALB, explain ECS traffic shifting under the hood, share rollout patterns for stateful apps, and hand you a 10-step runbook to use today. Less guessing. More green graphs.
Here’s the 60-second version. ALB is Layer 7: HTTP headers, cookies, path or host rules, and routing. NLB is Layer 4: raw TCP or UDP, static IPs, TLS passthrough or termination, and very low latency. For long-lived connections or game-level performance, pick NLB. For path rules or WAF, pick ALB.
AWS says NLB handles millions of requests per second with ultra-low latency. That’s your north star if you care about real-time loads.
A simple rule to choose: if your packet needs header logic or rules like /api versus /admin, go ALB. If your packet is a long stream, like game, chat, FIX, MQTT, or custom binary, go NLB. Some teams run both: ALB for web or app, NLB for real-time ports, behind the same ECS cluster.
Canary and linear cuts the failure blast zone. You don’t flip 100% of traffic at once. You start at 5–10%, watch errors and latency, then go forward or bail. This matters most for stateful or connection-heavy apps where fails cascade hard.
As Werner Vogels likes to remind us, everything fails all the time. Canarying lets you fail in private before you fail in public.
Bonus: gradual shifts make rollbacks boring, in the best way. If you only moved 10%, rollback is a flick, not a fire drill. MTTR drops, the pager stays quiet.
Before: blue or green and canary for NLB meant scripts, fragile listener swaps, or outside tools. Now: ECS manages the rollout, shifts traffic natively behind your NLB, and hooks into CloudWatch for health and rollback. Less YAML yoga, more safety.
Under the hood, ECS blue or green services tie into CodeDeploy traffic routing configs, canary or linear. You set the plan, attach CloudWatch alarms, and ECS plus CodeDeploy shift traffic between two target groups behind your NLB. If alarms fire, rollback is automatic. If metrics stay green, promotion is hands-off.
Linear deployments move traffic in fixed steps on a timer. Example: shift 10% every 3 minutes until 100%. If metrics go red, like error spikes, resets, or bad p99, ECS halts or rolls back. It’s a steady curve that’s easy to explain and reason about.
Practical tip: set steps based on peak traffic, not instance count. Ten percent at off-peak might be noise. Ten percent at peak is a real test.
Common defaults in CodeDeploy style setups: 10% every 1 minute, or 10% every 3 minutes. Pick intervals long enough to see effects on caches, pools, and GC pauses. Fast ramps tempt you, but slow ramps catch edge cases.
Canary tests a small slice first, like 5% for 10 minutes, then 100% if healthy. It’s perfect for schema changes, protocol tweaks, or new TLS configs. With NLB, connection stickiness matters a lot. Tune deregistration delay so in-flight sessions on the old task set don’t get dropped mid-chat.
Health is your contract. Use CloudWatch to watch:
Pro move: pair the canary window with a feature flag or config toggle. If you hit a subtle bug, like a weak handshake or keepalive mismatch, you can disable the feature while keeping the binary.
When the canary trips a wire, you need fast, clear rollback. ECS tracks deployment state and can return traffic to the prior task set. Configure:
Pro move: test rollback paths in staging with production-like patterns. If rollback isn’t tested, it’s hope, not a plan.
Also consider partial rollbacks. If one Availability Zone shows high resets or latency, pause promotion. Check AZ-level metrics before calling a global revert.
Long-lived TCP sessions hate surprises. Three levers matter most:
For chatty or custom binary protocols, test idle timeouts and keepalives. Canary with real session mixes, not just simple pings.
Two more practical notes:
NLB can use static IPs per Availability Zone or assigned Elastic IPs. That’s gold for partner allowlists, payment rails, or strict data paths. ECS handles task churn behind the scenes, so your egress IP stays stable while you ship updates.
TLS note: if you terminate TLS on NLB, manage certs with ACM and watch for TLS negotiation errors during rollouts. If you pass TLS through to targets, validate app-level cert rotation during canary.
Bonus: if partners require whitelisting, document exact NLB EIPs per AZ. Set change windows for rare IP moves, like AZ scaling or migration. With pinned EIPs, moves are rare.
If you need HTTP routing plus raw TCP or UDP, run a hybrid. ALB for web front-end, NLB for game, chat, or gateway ports. NLB and ALB isn’t either or, it’s a topology.
Add resilience:
You pay per load balancer hour and usage. Pricing counts new connections, active flows, and processed bytes into capacity units, plus data transfer. Turn on cross-zone load balancing only if you need it. It helps spread traffic but changes transfer costs. Read the pricing page, then estimate with real traffic histograms.
Rule of thumb: small, frequent canaries are cheap compared to one outage. MTTR drops when promotion is automated and rollback is instant.
Cost guardrails you’ll be glad for:
Build promotion gates on CloudWatch alarms tied to your SLOs. For TCP or UDP, you don’t get HTTP request metrics like ALB. Push custom app metrics, like auth errors or match fails, to CloudWatch.
Concrete signals to wire up:
If you’re writing an amazon ecs network load balancer example, show success and rollback paths. Real guides include what to do when things go sideways.
If you have hand-rolled listener swaps, this is your cue to retire the bash.
Imagine a chat backend on TCP 443 with TLS passthrough:
This is the point: canaries turn surprises into tweaks, not incidents.
Yes. Use ALB for HTTP features like host or path rules and WAF. Use NLB for TCP or UDP, static IPs, and very low latency. Many teams run ALB for web and NLB for real-time behind the same ECS cluster.
Linear shifts traffic in fixed steps on a schedule, like plus 10% every few minutes. Canary starts with a small percent, like 5–10%, for a bake period. If healthy, it jumps to 100%. Both can roll back fast if alarms fire.
They shouldn’t, if you set deregistration delay and health checks right. NLB keeps existing flows to targets until they close. Test real client behavior, keepalives and timeouts, in staging to confirm.
Target health, connection resets, active and new flows, processed bytes, and your app SLOs. Add custom metrics for domain errors like logins, matches, or protocol rejects.
NLB pricing uses load balancer hours and usage via capacity units, plus transfer. ALB uses LCUs tied to L7 features. For TCP or UDP without L7 needs, NLB is usually cheaper.
No. It makes it smoother. Canary and linear are flavors of traffic shifting inside blue or green. You still run old and new task sets, shift traffic, then retire the old when ready.
1) Pick your service and port, TCP or UDP. Ensure the ECS service uses blue or green so traffic shifting is available.
2) Attach an NLB with listeners per port. Confirm listener protocol, TCP, TLS, or UDP, matches your app. Enable Proxy Protocol v2 if targets expect it.
3) Create two target groups, current and new. Register existing tasks in group A, and configure the deploy to register new tasks in group B.
4) Enable health checks and set deregistration delay. Use TCP or TLS checks for L4. Set deregistrationdelay.timeoutseconds high enough to drain long sessions.
5) Define canary or linear, percent plus interval plus bake time. Start small, 5–10% for 5–10 minutes, and use longer bakes for protocol or cipher changes.
6) Add CloudWatch alarms for error rate, resets, and latency. Wire alarms to fail the deploy if thresholds break. Fast rollback beats slow debugging at 100%.
7) Deploy new task set and start at 5–10%. Warm caches and pools during canary so promotion won’t cause a cold-start wave.
8) Watch metrics; fix or roll back on alarms. Check per-AZ metrics and global ones, problems can be local.
9) Promote to 100% when stable. Keep the old task set briefly as a safety net until it survives peak load.
10) Decommission the old task set and confirm zero unhealthy targets. Clean up any temp alarms or feature flags you used for rollout.
End with a quick post-mortem: what surprised you, and what to automate next.
Here’s the truth: you don’t need heroics, you need guardrails. NLB brings the speed; ECS now gives you the wheel. Add observability and pricing sense, and you’ll ship stateful real-time systems without dread.
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