ariffazil/caddyfile-ro-bind-mount-patch

Skill: Patching Caddyfile When Bind-Mounted Read-Only

Problem

Patching /root/arifOS/Caddyfile (source) does NOT update what a running Caddy container sees when the file is bind-mounted as read-only (ro).

Symptom

• docker exec caddy cat /etc/caddy/Caddyfile shows OLD content after patch reports success
• docker cp <file> caddy:/etc/caddy/Caddyfile fails with: unlinkat ... device or resource busy
• Caddy continues serving stale config even after docker exec caddy caddy reload
• Root cause: the file is mounted ro from host /root/arifOS/Caddyfile → container /etc/caddy/Caddyfile:ro

Correct Fix (two-step)

Step 1: Patch the source file as normal:

patch /root/arifOS/Caddyfile <old> <new>

Step 2: Restart the Caddy container so it re-reads the source mount:

docker restart caddy

Then verify:

sleep 3 && curl -s https://arifos.arif-fazil.com/health

Why This Happens

Read-only bind mounts are enforced by the Linux kernel at the mount point. The container's view of the file is snapshot-at-start-time. A reload alone doesn't re-read the source — only a full container restart does.

Verification Command

Always confirm the container's actual config after patching:

docker exec caddy grep "reverse_proxy arifosmcp" /etc/caddy/Caddyfile

If it still shows old value → restart the container.

Relevant Volumes (arifOS stack)

• /root/arifOS/Caddyfile → /etc/caddy/Caddyfile:ro (Caddyfile, read-only mount)
• /root/sites/ → /var/www/html:ro (webroot, read-only mount)
• /root/volumes/caddy/data → /data (Caddy data dir)
• /root/volumes/caddy/config → /config (Caddy config dir)