From zero to VS Code how I tamed cPanel in Docker and built a real-time dev environment

From zero to VS Code: how I tamed cPanel in Docker and built a real-time dev environment

This was a full infrastructure troubleshooting journey. The goal was clear: edit cPanel core/plugin files from VS Code on the host and get immediate reflection inside the container, without manual copy loops.

What I needed to achieve

• run cPanel/WHM in AlmaLinux 8 containers for plugin development;
• preserve cPanel core state across container recreation;
• build reliable host-to-container real-time editing;
• avoid fragile docker cp workflows.

1) overlay2 teardown failure

I hit this during cleanup:

Error response from daemon: container [HASH]: driver "overlay2" failed to remove root filesystem ... dnsadmin_log: operation not permitted

I treated it as immutable/append-only attribute or lock residue in the layer.

Fix path executed:

systemctl stop docker
chattr -e -i -a /var/lib/docker/overlay2/[LAYER_HASH]/diff/usr/local/cpanel/logs/dnsadmin_log
chattr -R -i /var/lib/docker/overlay2/[LAYER_HASH]/diff/usr/local/cpanel/logs/
rm -rf /var/lib/docker/containers/[CONTAINER_HASH]*
systemctl start docker

2) /etc/fstab timing conflict in Compose bootstrap

I had touch /etc/fstab in startup, but file disappeared during boot due to mount timing over /etc.

I hardened the compose command with:

• early fstab creation;
• required package bootstrap (wget, perl, hostname, etc.);
• SSH/root setup;
• conflicting service disablement;
• pre-systemd final fstab check.

That removed bootstrap instability.

3) Volume architecture decision

I explicitly avoided direct bind mount of an arbitrary host folder into /usr/local/cpanel, because it can hide install targets and break initialization.

I used a named volume:

volumes:
  - cpanel_core:/usr/local/cpanel

volumes:
  cpanel_core:

This kept persistence clean and aligned with Docker-managed copy-up behavior.

4) Mapping volume source and creating VS Code bridge

I discovered mount source path with:

docker inspect cpanel-server --format '{{ range .Mounts }}{{ .Source }}:{{ .Destination }}{{ "\n" }}{{ end }}'

Then exposed it to my dev workspace:

ln -s /var/lib/docker/volumes/project_cpanel_core/_data /home/user/dev

5) Final validation

Initial file test used wrong syntax. Correct absolute path test:

touch /usr/local/cpanel/teste.txt

The file appeared on host immediately, confirming real-time mirror.

Then I ran cPanel installer inside the container:

docker exec -it cpanel-server bash -c "cd /home && curl -o latest -L https://securedownloads.cpanel.net/latest && sh latest"

Post-install validation on host:

ls -la /home/user/dev/ | wc -l
71

Operational conclusion

Final setup is stable for plugin development: named volume persistence, host bridge for VS Code, and defensive bootstrap that survives real-world container lifecycle issues.

Related project: https://perciocastelo.com.br/projetos/en/docker-cpanel-dev-environment.html Repository: https://github.com/sr00t3d/docker-cpanel

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