Amazon Cloud Account Recharge: AWS Global Accelerator Terminal Point Health Check Fails to Distribute Traffic Diagnostic Guidelines
When monitoring the health of websites and crawling logs on a daily basis, my biggest headache is "the website cannot be opened" or "the access delay increases sharply". In the modern architecture of transnational business and globalization,
AWS Global Accelerator(GA)
With its dual fixed Anycast IP, extremely low latency based on AWS global backbone network and automatic failover mechanism, it has become the standard configuration for many overseas businesses and multinational sites.
However, in the actual operation and maintenance and SEO site maintenance, we often encounter such embarrassing scenes:
DNS has resolved to the static IP provided by GA, but users and search engine crawlers frequently receive timeout or 502/504 errors. In AWS console, the terminal point (Endpoint) is marked as Unhealthy (unhealthy), causing traffic to be completely unable to be distributed normally.
For SEO, the failure of the terminal point health check not only means that the user experience jump rate (Bounce Rate) soared, but also lead to the search engine Spider (such as Googlebot) crawl failure, index drop right and even keyword ranking precipitous decline.
This article will be from
Architecture principle, core fault scenario, 5-step deep diagnosis process
and also
Infrastructure security and account fund guarantee
(contains
AWS account recharge
Note) and other dimensions, for you to thoroughly analyze and solve this troubleshooting problem.
1. the health check mechanism of the AWS Global Accelerator
Before we start diagnosing, we need to figure out how the GA determines whether a terminal point (such as ALB, NLB, EC2, or Elastic IP) is "alive.
Unlike common DNS polling, GA proactively sends probe packets (TCP, HTTP, or HTTPS) to your endpoint through its globally distributed probe nodes (based on the Amazon Route 53 health check system).
[Client User/Search Engine Crawler]
│
▼
[AWS Global Accelerator (Anycast IP)]
│
(Health Check Health?) ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ► [Block Traffic/Transfer to Standby Area]
│ Yes
▼
[Terminal Point Endpoint: ALB / NLB / EC2 / EIP]
│
▼
[Backend Service Application]
The decision logic varies for different terminal point types:
EC2 Instance/Elastic IP (EIP):GA will directly check the health check protocol (T
CP/HTTP/HTTPS), port, and path to directly initiate probes to EC2 or EIP.
Application Load Balancer (ALB):GA reuses the health status of the target group of the ALB. If all Target Groups under the ALB are unhealthy (or if the Target Group is empty), the GA marks the ALB as Unhealthy.
Network Load Balancer (NLB): Also reuses the NLB target group state. It should be noted that as long as any target group under NLB is empty or unhealthy, GA will judge the whole NLB as unhealthy.
Five Core Causes and Troubleshooting Process of Health Check Failure of 2. Terminal Points
When you see the terminal point status turning red in the GA console (
Unhealthy
), you can follow the following criteria
"5-Step Deep Diagnosis"
Precise positioning:
-----------------------------------------------------------------------
| Diagnosis process for health check failure of terminal point |
-----------------------------------------------------------------------
│
[Step 1] Network and Security Group Check: Check whether the security group/NACL/firewall allow Route53 IP
│
[Step 2] Load Balancing (ALB/NLB) Status Check: Check the Health of Back-end Target Group
│
[Step 3] EC2/Application Layer Listening Troubleshooting: Verify Application Listening Port and Local Firewall Rules
│
ν-[Step 4] Weight and Traffic Dial (Traffic Dial) Verification: Confirm Configuration Non -0 Status
│
-[Step 5] AWS account status and service restriction investigation: confirm that the account is not in arrears (including AWS account recharge)
Step 1: Network security group (Security group) and firewall interception
This is the most common "low-level error" that causes health checks to fail ".
Trouble phenomenon: HTTP/HTTPS health check is configured, the path and port are correct, but the detection log always shows Timeout.
Root Cause: For EC2/EIP:GA relies on
The probe node of Amazon Route 53 performs a health check. If your EC2 security group (Security Group) or network ACL(NACL) only allows specific business IP addresses and blocks the IP address segment of the AWS Route 53 health checker, the probe packet will be silently discarded. For internal ALB(Internal ALB): If the ALB is deployed in a private subnet, the security group does not allow internal traffic from the GA service or the health check source IP, the detection will also fail.
Troubleshooting and resolution: Check the security group (Inbound Rules) attached to the endpoint. Confirm that inbound access to the Route 53 health check IP segment and service port is allowed (for EC2/EIP). If the operating system firewall (such as Linux iptables / nftables or Windows Firewall) is enabled, confirm that the detection traffic is not blocked.
Step 2:ALB/NLB backend Target Group exception
If your GA terminal point is a Application Load Balancer or a Network Load Balancer,
GA itself does not directly probe the EC2 instance at the back end, but reads the health status of ALB/NLB
.
Diagnostic focus: Open the EC2 console-> Target Groups. Checks whether the associated target instance (Targets) status is Healthy.
Common pit: HTTP status code mismatch: ALB expects the backend to return 200 OK by default. However, if your application root path/301/302 redirection and 301,302 is not added to the ALB health check configuration, ALB will determine that the backend is dead, thus triggering GA health check failure. NLB Cascading Failure: NLB requires that all associated target groups must be healthy. If NLB is bound to multiple Target Groups (for example, one HTTP 80 and one HTTPS 443), GA will directly mark the entire NLB as Unhealthy as long as any internal node of the Target Group is completely destroyed or empty.
Step 3: The application service is not listening normally or the HTTP response is abnormal.
When the terminal point is directly mounted by EC2, the failure of the application service itself is a common cause.
Troubleshooting command: Log in to the terminal point EC2 and use the netstat or ss command to check the service and health check port: Bash# Linux to check the port listening status netstat
-anp | grep :80# or use ss ss -tuln | grep :80
Manual Test Response: Directly Use curl to Simulate GA Health Check Request on EC2 Local or Test Machines in the Same VPC: Bashcurl -Iv ht
tp:// 127.0.0.1:80/healthcheck If the return 500 Internal Server Error, 404 Not Found, or the connection is rejected (Connection Refused), please fix the application logic or path configuration of the Web server (Nginx/Apache/Node.js/Java).
Step 4: Traffic dial (Traffic Dial) and terminal point weight (Weight) setting error
Sometimes the health check itself does not report an error, but the traffic is still not distributed, which is a "dead corner in configuration logic".
Traffic Dial (Traffic Dial): Percentage to control traffic in and out by region, the default value is 100 percent. If it is mistakenly modified to 0%, the regional endpoint group will no longer receive any traffic.
Weight of terminal point: Even if the status of the terminal point is Healthy, if its weight is set to 0, the GA will not issue any request to it.
Troubleshooting method: enter GA console, check Listeners -> Endpoint Groups in turn, check whether the Traffic dial is 100%, and whether the Weight of each terminal point is greater than 0.
Step 5: Risk of AWS Account Funds and Service Status (AWS Account Recharge and Resource Freezing)
After checking the network, security group, configuration and application, many technicians will ignore the lowest and most fatal reason--
AWS account status and billing exceptions
.
As a website optimization and operation and maintenance personnel, I have encountered such cases: the operation and maintenance team frantically checked Nginx configuration files and VPC routing tables, and after a long time of trouble, I finally found that it was
The credit card bound to the AWS account expires, causing the debit to fail, and the account enters the overdue quarantine protection state.
, some edge acceleration nodes and API services are restricted, resulting in abnormal health check and traffic route disconnection.
Why is "AWS Account Recharge" and Billing Compliance Important to GA?
Billing structure of Global Accelerator: GA is an advanced network service, and its billing consists of two parts-fixed hourly fee + data transfer in and out fee (DT-Premium). GA bills for multinational high-traffic sites typically grow faster.
Impact of Arrears on API and Health Checks: When AWS
When the account is in arrears (Overdue), the system usually does not immediately hard shut down all resources, but first restricts some Control Plane (control panel) API calls, or deactivates the dynamic scheduling function of some edge acceleration nodes. In this case, the health check status update between Route 53 and GA may be delayed or abnormal, resulting in traffic routing logic disorder.
Enterprise AWS account recharge suggestion: turn on Billing Alerts (bill alert): set up CloudWatch bill alert to automatically notify operation and maintenance and finance when the monthly budget reaches 80%. Multi-channel guarantee smooth recharge channel: for overseas enterprises, it is necessary to ensure that the bound credit card (such as Visa/Mastercard) has sufficient quota, or through AWS official partners (AWS Partner) for enterprise-level quota pre-recharge (support public-to-public transfer/invoice reimbursement). Timely completion of AWS account recharge can effectively prevent the risk of cloud resource suspension or network service degradation caused by fund blocking. Isolate test and production account: Isolate the production environment and test environment account where GA is located through AWS Organizations to prevent the normal operation of GA in the production environment from being affected by the test account arrears.
3. from the perspective of SEO: GA failure to hit the site ranking and coping strategies
As SEO optimizers, we must not only solve technical failures, but also evaluate and reduce the negative effects on the search engine side.
When the GA endpoint health check fails and the traffic is not distributed, the search engine crawler will encounter the following attacks:
Fault phenomenon
Search engine response
SEO Consequences
Connection Timeout/504 Gateway Timeout
Googlebot Crawl Budget Waste
New pages cannot be included, and old pages are not updated in time.
Death at Terminal Points in the Region Return to 502/503
Trigger the search engine "site down" protection mechanism
In the short term, the keyword ranking declines, while in the long term it is removed from the index.
Frequent Failover lead to delay fluctuations
Web Core Web Vitals (INP / LCP) Indicator Deterioration
The user experience score is reduced, which affects the search ranking of the mobile terminal.
SEO emergency disposal Checklist:
Configure multi-region Failover: Configure at least two Endpoint groups in different regions (for example, Tokyo and Singapore) in GA. When the health check of the primary area fails, GA will seamlessly switch the traffic to the standby area within a few seconds, so that the crawler and the user have no sense of perception.
Enable CloudWatch + SNS real-time alarm: monitor the HealthyEndpoi of GA
ntCount and UnhealthyEndpointCount indicators. Once the number of healthy terminals drops, the DingTalk/flying book/email notification will be triggered in the first place to fix the problem before the search engine crawls and reports errors on a large scale.
Set a reasonable DNS TTL: If GA has an irreversible large-scale failure, ensure that the TTL for domain name resolution is short (e.g. 300 seconds) so that DNS can be directly cut back to the source station ALB or CDN in case of emergency.
4. Summary and Checklist
AWS Global Accelerator is an extremely powerful global network acceleration tool, but "the greater the power, the greater the responsibility". Its health check mechanism is like a strict access control system. Any minor flaw in the network security group, application port response or account compliance problem may cause the health check to fail, thus blocking the traffic distribution.
To sum up, facing the GA terminal point
Unhealthy
To report an error, please remember the following diagnostic formula:
Check the release of the security group and the response of the target group. Three tests apply local listening, quad-core weight and dialing. Five confirm that the fund account is normal, and don't forget to recharge the AWS account.
By building a complete cloud infrastructure monitoring, formulating a standard troubleshooting process, and ensuring the health of AWS account funds, we can truly leverage the global acceleration advantage of Global Accelerator and escort the high availability of business and SEO echelon construction!
