Questions tagged [debugging]
Finding problems in a program and trying to solve these.
201 questions
0 votes
1 answer
285 views
Logs are not being printed out to the wildfly console
I got a problem with my wildfly server. I a trying to print logs, but they are not showing whatever changes to wildfly log configurations I am making. Here is the code with the initial class that runs,...
1 vote
0 answers
90 views
Strange interaction between UserDir and RedirectMatch in Apache (redirecting multiple slashes)
I have an Apache server (version 2.4.62-1~deb12u2 from Debian 12 “Bookworm”, currently the stable version of Debian) serving a site http://www.example.tld/ with UserDir activated, so http://www....
- 111
0 votes
0 answers
452 views
How to debug gpupdate?
My gpupdate can take upto 10 minutes to run instead of 40s. How can I debug gpupdate ? : PS C:\> ~/psh/time.ps1 gpupdate Updating policy... Computer Policy update has completed successfully. User ...
- 441
0 votes
1 answer
256 views
Why dovecot use "postfix_accounts.users" to retrieve mail user information after username/password auth?
I had set up a mail server in my Rocky Linux 9.1 that comes with postfix, dovecot and mysql (refer to https://computingforgeeks.com/how-to-setup-mail-server-on-centos/). Every thing is updated. (...
- 103
4 votes
2 answers
5k views
Debugging Prometheus OOMkilled despite 6Gi limits
I'm at the end of my patience with a prometheus setup leveraging kube-prometheus-stack 44.3.0 (latest being 45). I have two environments, staging and prod. In staging, my prometheus runs smoothly. In ...
- 151
2 votes
1 answer
29k views
Tips to Debug CURL with a client - (56) Recv failure: Connection reset by peer site
A client of mine is trying to connect to our site via CURL. The command they are running is: curl -Ik example.com The response they receive is: (56) Recv failure: Connection reset by peer site They ...
- 241
1 vote
1 answer
577 views
jcmd works in console but fails in script
I'm getting mad with what should be a simple task: a java process is running, runs out of memory and a script runs. SELinux is disabled. in setenv.sh : -XX:OnOutOfMemoryError='/opt/alfresco/scripts/...
1 vote
0 answers
3k views
How can I see which commands ansible runs and their output?
I'm new to Ansible, and yes I know this has already been asked many times, but I already tried to apply advice I saw elsewhere. I did export ANSIBLE_STDOUT_CALLBACK=debug and then ansible-playbook -...
- 311
1 vote
0 answers
868 views
Can Premature end of script headers be properly debugged? (getting the real error message?)
We are getting [Wed Aug 25 15:06:05.484053 2021] [proxy_fcgi:error] [pid 24792:tid 140550620227328] [client xxxx:40224] Premature end of script headers: index.php, referer: https://www.example.com/ [...
- 846
0 votes
0 answers
1k views
Debugging "upstream prematurely closed FastCGI request while reading upstream"
I am running an nginx + php-fpm setup. I recently ran into problem returning binary data to the Nginx server. Nginx show this in the error log: 2021/08/04 19:22:27 [error] 996463#996463: *1 upstream ...
- 201
1 vote
1 answer
2k views
/etc/login.defs settings not taken into account: password aging
The following is done on a Ubuntu 20.04 system. This is the scenario where I am facing an issue: I edit the password aging settings in the login.defs file Then I change the password of the user with ...
- 158
2 votes
1 answer
1k views
How to get line number of error that .htaccess apache2 is reporting in /var/logs/error.log
I get a internal server error after adding redirects to .htaccess - I've added 600 of them. I check /var/logs/error.log [Wed May 12 16:26:02.600394 2021] [core:alert] [pid 8071] [client 127.127.127....
- 491
2 votes
1 answer
20k views
What does `Accept-Encoding: gzip,deflate` mean?
Can someone explain what it means when I see Accept-Encoding: gzip,deflate when listening with ncat? Does it mean the body is compressed? And if so, how can I decompress it? $ nc -lnvp 4000 Ncat: ...
- 10.8k
0 votes
0 answers
181 views
Is it possible to install Windows Debugging Tools via Powershell?
I've installed LeanSentry on one of my web servers to try and diagnose some performance issues I've been having. I need to install Windows Debugging Tools (from the Windows SDK) to get some memory ...
- 101
0 votes
1 answer
2k views
tracking down a bash process for a df command
I’m using the tips on this SO thread. ps -awux|grep df root 15826 0.0 0.0 0 0 ? I< May22 0:00 [cifs-dfscache] myuser 3086246 0.0 0.0 216860 3212 ? Ss 16:06 ...
- 400
5 votes
2 answers
7k views
nginx. How to log ssl errors without blowing up the server logs
I have a web site, that is visited by many different mobile devices and embedded devices. Quite often I encounter the issue, that some devices cannot connect. The reasons can be: the device doesn't ...
- 297
-2 votes
1 answer
66 views
How to log a single-board computer events?
I have a single-board computer, I want to knows whats going on when it boot up and start up because i never get access to its BIOS, can I log the events/activities happening on the board when it get ...
- 97
1 vote
3 answers
4k views
How to verbose log dhcp messages with options values
I am trying to configure dhcp PXE server, but client is not booting as expected. Is there a way how you can watch transferred requested and responded options between client and server? I want to be ...
- 386
5 votes
1 answer
6k views
Ubuntu Server with systemd - how to get a backtrace or coredump?
I'm using Ubuntu 18.04 Server with systemd. Recently a program my department has developed crashed twice within a day with the following error: Jun 07 06:33:07 xxx systemd[1]: xxx.service: Main ...
- 175
0 votes
0 answers
30 views
How to extract system startup logs from guest esp. on boot failure?
Given you have a libvirt guest VM which has all possible startup logs verbosely enabled (kernel loglevel, syslogd, dmesg etc. depending on distro). How to extract these startup logs to the host ...
- 179
3 votes
1 answer
2k views
How to debug linux startup hang
My ubuntu system hangs on the startup. It hangs on [OK] items like usual on boot. Interestingly, I am able to ssh onto this machine, but the boot never finishes and login screen doesn't appear. What ...
1 vote
2 answers
277 views
Set ASPNETCORE_ENVIRONMENT in Google Cloud Flex App
I have an error in my asp.net core 2.1 app and would like to set the ASPNETCORE_ENVIRONMENT setting to Development so that I can better debug. There are samples for the appsettings.json file, but the ...
google-app-engine
4 votes
3 answers
14k views
Monitoring HTTP 5xx errors in an Azure App Service
The Azure App service UI used to have an ability to inspect 5xx errors directly. Since we starting using Azure, the UI has been changing almost constantly though, and this ability seems to have ...
- 159
1 vote
1 answer
5k views
Preview or debug (dry-run or trace) systemctl actions (start, stop, restart, etc.)
Without having to manually trace dependencies, e.g. with systemctl show or systemctl cat, and manually inspect the state of the system with systemctl status and systemctl list-units, is there a way to ...
- 943
9 votes
3 answers
12k views
Why is MemAvailable a lot less than MemFree+Buffers+Cached?
I'm running a Linux workstation without swap and I have installed earlyoom daemon to automatically kill some processes if I'm running out of RAM. The earlyoom works by monitoring kernel MemAvailable ...
- 1,332
0 votes
1 answer
158 views
How to interpret the debug output from Amavis->Spamassassin?
Could please someone explain how Spamassassin build the following strings: Oct 17 14:00:30 server amavis[29497]: (29497-02) SA dbg: uridnsbl: domain amazonaws.com in skip list, host sns.eu-central-1....
- 255
3 votes
2 answers
6k views
How do I Identify an anonymous process that's changing a system setting?
I see an anonymous process changing the time of my systemtime to UTC every 80 sec. Using the journalctl -f command I only see a message that says 'systemd[1]: time has been changed' but it doesn't ...
- 141
1 vote
0 answers
1k views
PHP FPM pool www - 100% spikes when executing scripts - how to debug
I am experiencing weird 100% spikes of cpu when loading drupal pages. It started several months ago and now Im trying to debug this. I moved same database and files to new hosting - everything runs ...
- 115
1 vote
1 answer
275 views
Why does my VM become slower during CPU-heavy tasks after some days of runtime?
I'm dealing with some strange problem for some time now: After some days of runtime, one of my VMs seems to become slower on CPU-heavy tasks. One example were this happens is reading virus signature ...
0 votes
1 answer
784 views
Network timeouts: how to debug?
I'm experiencing network timeouts when trying to fetch libraries from https://rubygems.org and I'd like to figure out why. It only seems to affect requests made from my home network. If I take my ...
- 101
0 votes
1 answer
1k views
What are all/most ways to enable/disable usage of async file-io in Linux?
To make a long story short, I have two identical servers hosting VMs using VirtualBox and both servers host one VM each nearly setup the same way, only that one is production and the other for ...
0 votes
0 answers
298 views
How to enable/install kernel-debuginfo linux-4.14.14 on amzn-linux? [duplicate]
I'm on an amzn-linux instance which by default runs linux-4.9. I've compiled and booted linux-4.14.14 from source and I've compiled systemtap from source. Now I'd like to get them both working nicely ...
- 2,765
0 votes
1 answer
5k views
NTP rejecting upstream due to "peer_dist"
Currently NTP is rejecting its upstream and is drifting quite badly (15 seconds of offset so far and growing). When checking the reason using ntpq the flash code is flash=400 peer_dist. Checking the ...
- 101
1 vote
1 answer
5k views
How to check why a write failed? [closed]
If I was to debug a service on a machine and I determined that a write was failing, how could I check why the write failed? I know the system call in C will return -1 and then we can check what ...
- 113
1 vote
1 answer
3k views
Can not connect right now. can not assign requested address?
We are experiencing high load on our dedicated servers lately. Users see the error message "can not connect right now. can not assign requested address" popping up randomly. We have 2 Linux ...
lipp
4 votes
1 answer
2k views
What might be causing repeated mmap/munmap in strace results?
I have a (node.js) application which is occasionally causing 100% CPU usage. I've attached to the process with strace when it's been in this state - but I don't know what to make if the strace output....
- 1,658
3 votes
1 answer
3k views
Debug DNS: What to do if host name resolution does not work as expected?
The current search results for "debug dns" don't reveal a guide-line what to do, if you (as user/client) think there is something wrong with the host name resolution. What steps can I do to narrow ...
- 3,891
1 vote
0 answers
63 views
ASP.NET MVC App Redirects Break in Azure
Info I'm developing a web application in ASP.NET MVC. It works great running locally (or even on a test server on my network). The moment I push it up to Azure, a couple of the redirects break ...
- 188
3 votes
2 answers
11k views
how to debug/troubleshoot collectd?
I have an issue with custom script using exec plugin. From shell the script works well and nothing useful in /var/log/collectd.log. LoadPlugin logfile <Plugin logfile> LogLevel info ...
- 2,507
3 votes
1 answer
8k views
How to debug/log 502 Bad Gateway from reverse proxy?
We're running a web service and hitting 502 Bad Gateway randomly. The 502 is reported by reverse proxy (Apache 2.4.x) while talking to backend server (Apache 2.4.x). The problem randomly re-appears ...
- 1,332
1 vote
0 answers
149 views
SSD bandwidth issue and analysis
I have Intel's P3700 SSD mounted on a Lenovo x3650 M5 server with two Intel Xeon E5-2630 v3 CPUs. The server is running Ubuntu 14.04 with 4.6.4 Kernel. I've been using fio to benchmark the SSD using ...
- 23
0 votes
0 answers
504 views
Drupal on Apache: Consecutive PHP errors "Maximum execution time of 240 seconds exeeded"
This Apache/MySQL server (Debian 8) running a Drupal site shows a strange behaviour: There's always one Apache process running with 100% CPU utilization (according to htop). Every four minutes (~240 ...
- 404
3 votes
0 answers
1k views
Obtaining a Crash Dump from a dying IIS ASP.NET Worker Process
(Not sure if this is an IIS problem or not, so if this is better suited for SO I'll happily move it...) We have an IIS-hosted application that is sporadically dying, and the event logs claim that the ...
- 131
1 vote
0 answers
930 views
debugging "eth interface using wrong IP" on server
My Uni provided me two hostnames and static IPs for two interfaces on my Fedora Server 23. My idea is to use one hostname for production and another for dev branches. It should work as: bio-db.uni.edu ...
5 votes
1 answer
7k views
Verifying RADIUS server is sending the correct certificates?
How can I see the TLS (SSL) certificates that my RADIUS server is using, to make sure it is sending the correct certificate and chain? I am implementing 802.1x authentication with a RADIUS server, ...
- 1,036
0 votes
1 answer
290 views
Log all bash actions with multiple scripts
Using the command below, I can log all actions that happened inside that script. bash -x script.sh Sadly, the script calls another script, which does not have the -x setting active then, i.e. the ...
- 101
1 vote
1 answer
3k views
Occasional "failed to respond" from AWS hosted Elasticsearch
We have an Elasticsearch cluster hosted on Amazon Elasticsearch Service (AWS). We are using the Jest Java HTTP Rest client for ElasticSearch. Every now and then (perhaps 1 in 10,000 requests), it ...
- 824
2 votes
0 answers
1k views
How to reliably capture Linux kernel log messages in case of a system debilitating crash (BUG, panic)?
I'd like to have access to the lines/tracebacks/whatever whispered by the kernel right before dying. This has proven problematic, because all interfaces I have access to become disabled. Post-reboot, ...
- 815
2 votes
0 answers
463 views
Show or log long queries with values instead placeholders
I have any very long sql query in postgresql. I tried show what postgress do with: select * from pg_stat_activity unfortunately I see something like: select some_fields from anytable1 anytable2 ...
- 348
1 vote
2 answers
2k views
bizarre 404 on nginx
i have a location block for / that passes any virtual paths to index.php as instructed on the nginx pitfalls page. i have been using this setup for some time now, but recently i have noticed that some ...
- 202