Service Discovery — Env-Based Approach

Problem with internal.zlh DNS

Service-to-service calls in the API and agent currently use internal.zlh FQDNs (e.g. zpack-velocity.internal.zlh:8081). This introduces:

DNS resolution overhead on every call
Silent failure if Technitium is down or slow
Hard-to-diagnose timing issues during provisioning
An extra dependency in the critical path for container creation

The provisioning + DB consistency issues may be partly caused by DNS resolution delays or failures during rapid create/delete cycles.

Recommended Approach — Env File

Replace internal.zlh FQDNs in service-to-service calls with env vars backed by IPs. Each VM reads from its own .env or services.env file.

Example services.env

ZPACK_API_URL=http://10.60.0.18:4000
ZLH_ARTIFACTS_URL=http://10.60.0.17
ZPACK_VELOCITY_URL=http://10.70.0.10:8081
ZLH_PBS_URL=http://10.60.0.24
ZLH_MONITOR_URL=http://10.60.0.25
ZLH_DNS_URL=http://10.60.0.14

Benefits

Zero DNS resolution — direct IP, always predictable
No dependency on Technitium for service calls
If IPs ever change, update one env file per VM — no DNS record changes needed
Easier to debug — no DNS layer to troubleshoot
Faster provisioning — no resolution delay in the critical path

Scope

Services that need to change:

Service	Current	Change to
zpack-api	`zpack-velocity.internal.zlh:8081`	`ZPACK_VELOCITY_URL` env var
zpack-api	`zlh-artifacts.internal.zlh`	`ZLH_ARTIFACTS_URL` env var
zpack-portal	`zpack-api.internal.zlh`	`ZPACK_API_URL` env var (server-side only)
zlh-agent	artifact server FQDN	`ZLH_ARTIFACTS_URL` env var

What internal.zlh is still useful for

Human navigation: SSH, browser access to admin tools, Proxmox
Non-critical paths where DNS resolution timing doesn't matter
Documentation and reference

internal.zlh should NOT be used in:

Provisioning hot path
Agent → artifact server calls
API → Velocity calls
Any call that happens during container create/delete

Current IPs (Detroit host)

See INFRASTRUCTURE.md for full IP table. Key service IPs:

Service	IP
zpack-api	10.60.0.18:4000
zpack-portal	10.60.0.19
zlh-artifacts	10.60.0.17
zpack-velocity	10.70.0.10:8081
zlh-dns (Technitium)	10.60.0.14
zlh-proxy (Caddy)	10.60.0.16
zpack-proxy (Traefik)	10.70.0.11
zlh-monitor	10.60.0.25
zlh-back (PBS)	10.60.0.24

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