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11 votes
Accepted

What is HEALTHCHECK really used for when running Docker in swarm mode?

You setup healthchecks the same ways your first link suggests. All those ways will tell docker what command to run, how often to run it, etc. If you use docker run to start a container, the UI will ...
Bret Fisher's user avatar
  • 3,983
8 votes
Accepted

AWS: Target.FailedHealthChecks - Site always in "severe" state

It seems the error was caused by a Heath Check for the Application Load Balancer, not the Elastic Beanstalk application. The ALB needs its target changing in a different place (see the documentation). ...
Django Reinhardt's user avatar
6 votes

How to set up ELB health checks with multiple applications running on each EC2 instance?

On 11 August 2016, Amazon introduced Application Load Balancers. These let you specify multiple Target Groups, each with its own type of health check. So this is now possible using a single load ...
Thomas's user avatar
  • 811
6 votes
Accepted

HAproxy: Run script on health check change

I would probably do this with an external check script and use this to control the rise and fall values. Then when you meet the rise or fall value you can run your own script. Set the rise and fall in ...
Ben's user avatar
  • 76
6 votes
Accepted

Verify internal NTP server is sending the correct time?

TL;DR: Configure your NTP server according to best current practices. (Shameless self-promotion warning.) Use my ntpmon check if your monitoring solution uses collectd, Nagios, or telegraf. Long ...
Paul Gear's user avatar
  • 4,622
5 votes

DNS layer with service discover as resolver not SRV

I believe everyone focusses too hard on the BIND server. According to the Consul documentation, you only need BIND to forward the DNS queries from port 53 to port 8600 which Consul uses. Consul is the ...
Tommiie's user avatar
  • 5,695
4 votes
Accepted

Broken GKE Backend Health Check Default

Discovered that the answer is A. No B. No by reading the Kubernetes Ingress Github README.MD: "..currently we just rely on kubernetes service/pod liveness probes and force pods to have a / ...
Benji L.'s user avatar
4 votes
Accepted

HAProxy health check for a single backend

It makes sense to healthcheck a single server to allow for a 'circuit breaker' scenario. Imagine your backend is accepting TCP connections but is unable to generate a response. Client apps connecting ...
Jason Martin's user avatar
  • 5,113
4 votes

Where are the Google Health check logs

Health check logs are now available (in Beta, at the time of writing) via Cloud Logging. (Note: Legacy Health checks are not supported) In Cloud Logging (formerly known as Stackdriver) use a filter ...
Drew's user avatar
  • 235
4 votes

DNS layer with service discover as resolver not SRV

Well... sad-to-say, you're kinda going to have a hard time doing this in production. 50% of the problem is updating the "healthy" records to point to the healthy server. There are ways of doing ...
TheCompWiz's user avatar
  • 7,399
4 votes
Accepted

Disable AWS ELB health check

Rather than disabling it completely, have your webserver serve a static HTML page (thus bypassing node entirely) and check that URL. Alternatively, morgan appears to have a skip function you can use ...
ceejayoz's user avatar
  • 33.2k
4 votes
Accepted

What happens when a pod fails for readiness health check?

Answering first your main question in the title. Quoting the official documentation on readiness probe concept A pod with containers reporting that they are not ready does not receive traffic ...
Nepomucen's user avatar
  • 306
4 votes
Accepted

Health Tests on NVMe

SMART self-test were conceived for mechanical disks. SATA SSDs almost completely mirrors earlier HDD interface-level behavior supporting such self-test but not doing very much when you run it, ...
shodanshok's user avatar
  • 51.2k
3 votes

Using a GCP Global Load Balancer HTTP health check, is it possible to POST instead of GET?

Try a TCP or SSL health check (it is intended for non-HTTP(S) traffic), which will only check if the port is open. In theory, you can provide a small request string to build a static HTTP request, but ...
John Mahowald's user avatar
3 votes
Accepted

Should things like database performance be included in a healthcheck

You probably shouldn't monitor the database performance via the application's health check paths - some dangerous cases can occur. Say you use ASG's within AWS and use the LB healthchecks for ...
Brennen Smith's user avatar
3 votes

Where are the Google Health check logs

I was troubleshooting a similar problem, the environment was including HTTPS load balancer and Managed Instance group Searched the available documentation no trace to access that logs, finally raised ...
IrfanM's user avatar
  • 31
3 votes
Accepted

Apache load balancer: health check with long timeout

My problem was not about the timeout: the health check started to work as desired once I set a ProxyHCExpr. I noticed this by looking at the requests made to the status page on the backend nodes: ...
simlev's user avatar
  • 1,145
3 votes

Verify internal NTP server is sending the correct time?

Sure, the standard approach is to use the bundled NTP client called ntpq. This utility can be used to display the connected servers, their reachability, time difference and jitter. Here's the example:...
drookie's user avatar
  • 8,876
3 votes
Accepted

How to avoid duplicate health-check for the real same server in Haproxy?

You can use the track directive to follow the status of another server. In your case the second server line would be: server proxy2 127.0.0.1:9999 track main-proxy1/proxy1
wurtel's user avatar
  • 3,949
3 votes

AWS Elastic Load Balancer and target group health check fail for no apparent reason

I had the same problem, it took me a long time to find where is the error that may cause Classic Load balancer "Out Of Service" error. Go to "Health Check" > edit "Ping target" from "Http" to "TCP" ...
user516489's user avatar
3 votes

Health Tests on NVMe

Get the NVME test client installed sudo apt install nvme-cli Find the drive you want to check nvme list sudo nvme smart-log /dev/nvme0n1 There are some other self-test commands you can run with this ...
jamboNum5's user avatar
  • 401
2 votes

how to install healthcheck module in nginx

It looks like the nginx module ngx_http_upstream_module will do what you want. It has health checks for the backends too. You will probably find that your Distro supplied nginx has all of this ...
user9517's user avatar
  • 116k
2 votes
Accepted

ARR Web Farm Health Test sends hundreds of requests

According to this comment on Scott Forsyth's blog, this can happen when you have a web farm on a server with multiple app pools: The problem is that ARR doesn't have a dedicated worker process to ...
mattgrayson's user avatar
2 votes

Haproxy http response timeout check

You need to have health checks in place https://www.haproxy.com/doc/aloha/7.0/haproxy/healthchecks.html. You specifically need check_timeouts "timeout check : time let to the server to answer the ...
Alex H's user avatar
  • 1,824
2 votes

Expose Windows system health over HTTP, machine-readable?

Alright- not exactly what you were looking for, but I was bored and this is a trivial issue to solve. Here is a little flask application: #!/usr/bin/env python import psutil import flask import json ...
Brennen Smith's user avatar
2 votes

Expose Windows system health over HTTP, machine-readable?

If by "off the shelf" you mean "native to the OS", then no*. The common native methods of gathering Windows performance statistics are Perfmon (TCP 445), WMI (TCP 445) , or SNMP (UDP 161/162). Are ...
mfinni's user avatar
  • 36.3k
2 votes

Configuring correct firewall settings for GCP HTTP load balancer

As the global forwarding rule is configured on port 80 but the backend instances are serving traffic on port 8545, two separate firewall rules need to be created to allow traffic from 130.211.0.0/22 ...
Ishtiaque's user avatar
2 votes

How to respond to http health check at a particular url while redirecting other traffics?

You can set the Health check to work with any port you define, as indicated in the documentation. You can use the UI or the command line when creating the health check: $ gcloud compute health-checks ...
Watacroft's user avatar
  • 178
2 votes
Accepted

503 ALB health check HAProxy

You need to add a default_backend for your frontend 443
nuster cache server's user avatar
2 votes
Accepted

GCP Load Balancer very high health check frequency

This is actually an expected behavior, since the Google probers actually send more requests than your health check interval. But your backend health check will be marked healthy or unhealthy depending ...
alrashid villanueva's user avatar

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