WHITEWHALE
Knowledge base
Practical VPS guides: security, networking, deployments, backups, and troubleshooting.
Category
Backups
Backups: strategy
What and how to back up.
Web
Cloudflare: DNS and redirect loops
Avoid ERR_TOO_MANY_REDIRECTS.
Troubleshooting
CPU 100%: quick triage
top/ps.
Security
Create a user + sudo and disable root login
A basic production hygiene step.
Linux
Cron: scheduling
crontab example.
Troubleshooting
Disk space: quick troubleshooting
df/du + sort by size.
Networking
DNS: troubleshooting
resolvectl/dig.
Docker
Docker Compose: basic example
A minimal compose for an app.
Docker
Docker: disk cleanup
Prune safely.
Docker
Docker: install on Ubuntu
docker + compose plugin.
Security
Fail2ban for SSH
Auto-ban IPs after failed attempts.
Getting started
First SSH login to your VPS
How to connect and common errors.
Networking
IPv6 basics
addr/route.
Troubleshooting
journalctl: systemd logs
Errors and follow.
Security
known_hosts: fingerprint warning
Safe update.
Web
Let's Encrypt + nginx
When TLS is terminated on the origin.
Getting started
New VPS checklist
First hour.
Troubleshooting
Nginx 502/504
Quick checklist.
Security
Nginx rate limiting
limit_req for login/registration.
Web
Nginx reverse proxy: route /api to backend
Frontend on 3000, API on 8081.
Web
Nginx security headers
A basic set.
Web
Nginx: static site
Minimal server block.
Troubleshooting
OOM killer
Find OOM in logs.
Linux
Permissions
chmod/chown basics.
Backups
PostgreSQL: backup/restore
pg_dump and pg_restore.
Web
PostgreSQL: basic tuning
Do not set work_mem too high.
Web
PostgreSQL: install
Local-only, do not expose ports unnecessarily.
Backups
Rsync backup
To a second server.
Security
SSH keys: passwordless login
Generate an ed25519 key and install it on the server.
Troubleshooting
SSH lockout: recover access
Console/Rescue and revert.
Networking
SSH tunnel (port forwarding)
Access services without opening ports.
Security
sshd_config: minimal hardening
Keys only, no root.
Linux
System updates
A quick security baseline.
Linux
systemctl: manage services
Status, restart, enable, logs.
Linux
systemd unit: template
Autostart an app.
Linux
Timezone and locale
Keep logs and apps consistent.
Security
UFW: basic firewall
Allow only required ports.
Linux
VPS swapfile
Create a swapfile and persist it.
Security
What ports are listening
Audit with ss/lsof.
Getting started
Windows: SSH key without ssh-copy-id
Manual authorized_keys.