Redis out of memory fix
When runned out of memory and redis fail
- try to stop everything with excessive usage of RAM
- fix redis db file with ./redis-check-aof --fix fdbfilename.aof
debug
Meassure connection time with curl
Get response time with curl:
Total time
curl -o /dev/null -s -w 'Total: %{time_total}s\n' https://www.google.com
Establish connection/time to first byte/total time
Dig with trace
For a dig with dns request flow response use
dig hostname.tld +trace
Bash set builtin -> bash debug
Set at the beginning of bash script:
set -Eeuxo pipefail
set -e
The -e option will cause a bash script to exit immediately when a command fails.
Tools
nmap - checking open ports and footprinting
MSF - Metasploit framework
DIRB - enumerate files on webserver
Wireshark - network analytics
Wfuzz - bruteforcing web applications
sqlmap - detection and exploitation of SQL injection flaws
Get docker container ip addresses`
Get docker ip addressesdocker inspect -f '{{.Name}} - {{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $(docker ps -aq)
Network testing with netcat (nc)
In order to pest whether is network port accessible, either udp or tcp.
Can server listen on udp port 5000 ?
Example with UDP port!
Server sidencat -ulp 5000
Client sidencat -u XXX.XXX.XXX.XXX 5000
Check logs via systemd
journalctl -u service.name
Slow system boot reason
List systemd service start time systemd-analyze blame
Check gitlab status
Check complete gitlab status of running services
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production